抽象语法树的应用样例

在上一篇文章java抽象语法树（AST）中已经介绍了部分定义语法树的的节点，接下来在这篇将会通过样例代码以及注释介绍如何使用语法树节点来生成setter、getter、toString、hash、equal 等方法。

需要通过注解处理器生成 setter、getter、toString、hash、equal的类如下

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@Service
public class DemoC {
    String var1;
    String var2;
    Integer tempInt;
    Double tempDouble;
    DemoA demoA;
    int temp;
}

语法树的访问是通过继承 TreeTranslator ，并且重写了 visitClassDef 方法来实现访问 DemoC 类通过语法节点来访问 DemoC 中的变量。

setter 方法生成样例

产生类似于 public void setter(int a){this.a = a;} 的代码，需要用到的语法树节点分别有 JCModifiers、JCExpression、JCVariableDecl、JCStatement、JCBlock

定义 public 可以使用 treeMaker.Modifiers(Flags.PUBLIC)

定义 void 返回类型可以这样使用 treeMaker.TypeIdent(TypeTag.VOID)

定义方法名称 这可以 通过 Names 工具来实现，比如 name.fromString(“setA”);方法名中的大小写字母这些细节可以通过字符串截取其中一个字符来实现。

参数 的定义可以这样treeMaker.VarDef(treeMaker.Modifiers(Flags.PARAMETER),jcVariableDecl.name,jcVariableDecl.vartype,null)来实现。

最后 this.xxx = xxx; 语句的构建通过 treeMaker.Exec( treeMaker.Assign( treeMaker.Select(treeMaker.Ident(names.fromString("this")),jcVariableDecl.name), treeMaker.Ident(param.name)))

详细的代码如下：

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/**
 * 生成 Setter 方法
 * @param jcVariableDecl
 * @return
 */
public JCTree.JCMethodDecl makeSetterMethod(JCTree.JCVariableDecl jcVariableDecl){
    JCTree.JCModifiers modifiers = treeMaker.Modifiers(Flags.PUBLIC);
    // 返回类型
    JCTree.JCExpression returnType = treeMaker.TypeIdent(TypeTag.VOID);
    // 方法名称
    Name methodName = getSetterMethod(jcVariableDecl);
    // 参数
    List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
    JCTree.JCVariableDecl param = treeMaker.VarDef(
        treeMaker.Modifiers(Flags.PARAMETER),
        jcVariableDecl.name,
        jcVariableDecl.vartype,null);
    //设置形参这一句不能少，不然会编译报错(java.lang.AssertionError: Value of x -1)
    param.pos = jcVariableDecl.pos; 
    jcVariableDeclList = jcVariableDeclList.append(param);
    
    // 构建语句  //this.xxx = xxx;  setter方法中的赋值语句
    JCTree.JCStatement statement = treeMaker.Exec(
        treeMaker.Assign(
            treeMaker.Select(treeMaker.Ident(names.fromString("this")),jcVariableDecl.name),
            treeMaker.Ident(param.name)));
    List<JCTree.JCStatement> statementList = List.nil();
    statementList = statementList.append(statement);

    JCTree.JCBlock jcBlock = treeMaker.Block(0,statementList);
    // 泛型参数
    List<JCTree.JCTypeParameter> typeParameters = List.nil();
    // 异常抛出列表
    List<JCTree.JCExpression> throwsClauses = List.nil();
    JCTree.JCExpression defaultValue = null;//非自定义注解类中的方法，defaultValue为null

    // 构建settter 方法
    JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(modifiers,
                                                           methodName,
                                                           returnType,
                                                           typeParameters,
                                                           jcVariableDeclList,
                                                           throwsClauses,
                                                           jcBlock,defaultValue);
    return jcMethodDecl;
}
getter 方法生成样例
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/**
 * 生成Getter 方法
 * @param jcVariableDecl
 * @return
 */
public JCTree.JCMethodDecl makeGetterMethod(JCTree.JCVariableDecl jcVariableDecl){
    JCTree.JCModifiers modifiers = treeMaker.Modifiers(Flags.PUBLIC);
    JCTree.JCExpression returnType = jcVariableDecl.vartype;
    // 方法名
    Name methodName = getGetterMethod(jcVariableDecl);

    // 构建语句 this.var
    JCTree.JCStatement statement = treeMaker.Return(
            treeMaker.Select(
                    treeMaker.Ident(
                            names.fromString("this")),jcVariableDecl.name));

    List<JCTree.JCStatement> statementList = List.nil();
    statementList = statementList.append(statement);
    // 构建代码块
    JCTree.JCBlock jcBlock = treeMaker.Block(0,statementList);
    // 泛型参数列表
    List<JCTree.JCTypeParameter> typeParameters = List.nil();
    // 参数类型
    List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
    // 异常抛出列表
    List<JCTree.JCExpression> throwsClauses  = List.nil();
    JCTree.JCExpression defaultValue = null;//非自定义注解类中的方法，defaultValue为null

    JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(modifiers,
                                                           methodName,
                                                           returnType,
                                                           typeParameters,
                                                           jcVariableDeclList,
                                                           throwsClauses,jcBlock,defaultValue);
    return jcMethodDecl;

}
toString 方法生成
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/**
 * 生成 toString 方法
 * @param jcClassDecl
 * @return
 */
public JCTree.JCMethodDecl makeToStringMethod(JCTree.JCClassDecl jcClassDecl){

    List<JCTree.JCVariableDecl> vars = List.nil();
    List<JCTree> jcTreeList = jcClassDecl.defs;
    for (JCTree jcTree: jcTreeList){
        if (jcTree instanceof JCTree.JCVariableDecl){
            JCTree.JCVariableDecl var = (JCTree.JCVariableDecl) jcTree;
            vars = vars.append(var);
        }
    }

    List<JCTree.JCAnnotation> jcAnnotationList = List.nil();
    // 方法注解
    JCTree.JCAnnotation jcAnnotation = treeMaker.Annotation(memberAccess("java.lang.Override"),
                                                            List.nil());
    jcAnnotationList = jcAnnotationList.append(jcAnnotation);
    JCTree.JCModifiers jcModifiers = treeMaker.Modifiers(Flags.PUBLIC,jcAnnotationList); // 方法修饰词
    JCTree.JCExpression returnType = memberAccess("java.lang.String"); // 返回类型
    Name name = names.fromString("toString"); // 方法名

    // "DemoC{
    JCTree.JCExpression jcExpression = treeMaker.Literal(jcClassDecl.name + "{");
    for (int i=0; i<vars.size(); i++){
        JCTree.JCVariableDecl var = vars.get(i);
        if (i!=0){
            jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,
                                            jcExpression,
                                            treeMaker.Literal("," + var.name.toString()+"="));
        }else {
            // 构建语句  var=
            jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,
                                            jcExpression,
                                            treeMaker.Literal(var.name.toString()+"="));
        }

        if (var.vartype.toString().contains("String")){
            // var='"+
            jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Literal("'"));
        }
        // var='"+var
        jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Ident(var.name));
        if (var.vartype.toString().contains("String")){
            // var='"+var+'"
            jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Literal("'"));
        }
    }
    jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Literal("}"));

    JCTree.JCStatement jcStatement = treeMaker.Return(jcExpression);
    List<JCTree.JCStatement> statementList = List.nil();
    statementList = statementList.append(jcStatement);
    JCTree.JCBlock jcBlock = treeMaker.Block(0,statementList);
    // 参数列表
    List<JCTree.JCVariableDecl> variableDecls = List.nil();
    // 形参列表
    List<JCTree.JCTypeParameter> jcTypeParameters = List.nil();
    // 异常列表
    List<JCTree.JCExpression> throwableList = List.nil();
    JCTree.JCExpression defaultValue = null;

    JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(jcModifiers,
                                                           name,
                                                           returnType,
                                                           jcTypeParameters,
                                                           variableDecls,
                                                           throwableList,jcBlock,defaultValue);
    return jcMethodDecl;
}
hash 方法生成
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/**
 * 生成 hash 方法
 * @param classDecl
 * @return
 */
public JCTree.JCMethodDecl makeHashMethodDecl(JCTree.JCClassDecl classDecl){
    List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
    List<JCTree> jcTreeList = classDecl.defs;
    for (JCTree jcTree : jcTreeList){
        if (jcTree instanceof JCTree.JCVariableDecl){
            JCTree.JCVariableDecl jcVariableDecl = (JCTree.JCVariableDecl) jcTree;
            jcVariableDeclList = jcVariableDeclList.append(jcVariableDecl);
        }
    }

    // Override 方法注解
    JCTree.JCAnnotation jcAnnotation = treeMaker.Annotation(memberAccess("java.lang.Override"),
                                                            List.nil());
    List<JCTree.JCAnnotation> jcAnnotationList = List.nil();
    jcAnnotationList = jcAnnotationList.append(jcAnnotation);

    // 修饰方法关键字
    JCTree.JCModifiers jcModifiers = treeMaker.Modifiers(Flags.PUBLIC,jcAnnotationList);
    // 返回类型
    JCTree.JCExpression returnType = treeMaker.TypeIdent(TypeTag.INT);
    // 方法名称
    Name methodName = names.fromString("hashCode");
    // 异常
    List<JCTree.JCExpression> throwableList = List.nil();
    // 方法体
    List<JCTree.JCExpression> var1 = List.nil();
    List<JCTree.JCExpression> var2 = List.nil();

    for (JCTree.JCVariableDecl jcVariableDecl : jcVariableDeclList){
        //var1 = var1.append(typeTranslator(jcVariableDecl.vartype));
        var2 = var2.append(treeMaker.Ident(jcVariableDecl.name));
    }

    JCTree.JCExpression jcExpression = treeMaker.Apply(var1,
                                                       memberAccess("java.util.Objects.hash"),var2);
    JCTree.JCStatement jcStatement = treeMaker.Return(jcExpression);
    List<JCTree.JCStatement> jcStatementList = List.nil();
    jcStatementList = jcStatementList.append(jcStatement);

    JCTree.JCBlock jcBlock = treeMaker.Block(0,jcStatementList);

    // 泛型变量
    List<JCTree.JCTypeParameter> jcTypeParameterList = List.nil();
    // 变量列表
    List<JCTree.JCVariableDecl> variableDeclList = List.nil();

    //
    JCTree.JCExpression defaultValue = null;

    JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(jcModifiers,
                                                           methodName,
                                                           returnType,
                                                           jcTypeParameterList,
                                                           variableDeclList,
                                                           throwableList,jcBlock,defaultValue);
    return jcMethodDecl;
}
equal 方法生成
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/**
 * 生成 equal 方法
 * @param classDecl
 * @return
 */
public JCTree.JCMethodDecl makeEqualsMethod(JCTree.JCClassDecl classDecl){

    JCTree.JCExpression extend =  classDecl.extending;
    // 提取类中定义的变量
    List<JCTree> jcTreeList = classDecl.defs;
    List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
    for (JCTree jcTree : jcTreeList){
        if (jcTree instanceof JCTree.JCVariableDecl){
            JCTree.JCVariableDecl var = (JCTree.JCVariableDecl) jcTree;
            jcVariableDeclList = jcVariableDeclList.append(var);
        }
    }
    // 方法注解
    JCTree.JCAnnotation jcAnnotation = treeMaker.Annotation(memberAccess("java.lang.Override"),List.nil());
    List<JCTree.JCAnnotation> jcAnnotationList = List.nil();
    jcAnnotationList = jcAnnotationList.append(jcAnnotation);
    // 方法关键修饰
    JCTree.JCModifiers jcModifiers = treeMaker.Modifiers(Flags.PUBLIC,jcAnnotationList);
    // 返回类型
    JCTree.JCExpression retrunType = treeMaker.TypeIdent(TypeTag.BOOLEAN);
    // 方法名称
    Name methodName = names.fromString("equals");
    // 泛型参数
    List<JCTree.JCTypeParameter> jcTypeParameters = List.nil();
    // 参数列表
    List<JCTree.JCVariableDecl> variableDecls = List.nil();
    JCTree.JCVariableDecl param = treeMaker.VarDef(treeMaker.Modifiers(Flags.PARAMETER),
            names.fromString("o"),memberAccess("java.lang.Object"),null);
    param.pos = classDecl.pos;
    variableDecls = variableDecls.append(param);
    // 异常列表
    List<JCTree.JCExpression> throwableList = List.nil();
    // 开始构建方法体
    //if (this == o) return true;
    List<JCTree.JCStatement> jcStatements = List.nil();
    JCTree.JCIf seqzero = treeMaker.If(treeMaker.Binary(JCTree.Tag.EQ,treeMaker.Ident(names.fromString("this")),treeMaker.Ident(names.fromString("o")))
            ,treeMaker.Return(treeMaker.Literal(true)),null);
    jcStatements = jcStatements.append(seqzero);

    // if (o == null || getClass() != o.getClass()) return false;
    JCTree.JCExpression getClassEqCondition = treeMaker.Apply(List.nil(),treeMaker.Select(treeMaker.Ident(names.fromString("this")),names.fromString("getClass")),List.nil());
    JCTree.JCExpression vargetClassEqCondition = treeMaker.Apply(List.nil(),treeMaker.Select(treeMaker.Ident(names.fromString("o")),names.fromString("getClass")),List.nil());


    JCTree.JCIf seqone = treeMaker.If(
        treeMaker.Binary(JCTree.Tag.OR,
                         treeMaker.Binary(
                             JCTree.Tag.EQ,
                             treeMaker.Ident(
                                 names.fromString("o")),
                             treeMaker.Literal(TypeTag.BOT,null))
            ,treeMaker.Binary(JCTree.Tag.NE,getClassEqCondition,vargetClassEqCondition))
            ,treeMaker.Return(treeMaker.Literal(false)),null);
           
    jcStatements = jcStatements.append(seqone);

    // BeanTreeTranslator that = (BeanTreeTranslator) o;
    JCTree.JCVariableDecl jcVariableDecl = treeMaker.VarDef(
        treeMaker.Modifiers(0),names.fromString(
            toLowerCaseFirstOne(classDecl.name.toString()))
            ,treeMaker.Ident(classDecl.name)
            ,treeMaker.TypeCast(
                treeMaker.Ident(classDecl.name),treeMaker.Ident(names.fromString("o"))
            )
    );
    jcStatements = jcStatements.append(jcVariableDecl);

    // return Objects.equals(messager, that.messager) &&
    //                Objects.equals(treeMaker, that.treeMaker) &&
    //                Objects.equals(names, that.names) &&
    //                Objects.equals(tep, that.tep);
    JCTree.JCExpression jcExpression = null;
    for (JCTree.JCVariableDecl var : jcVariableDeclList){
        List<JCTree.JCExpression> varType = List.nil();
        List<JCTree.JCExpression> varList = List.nil();

        //varType = varType.append(var.vartype);
        varList = varList.append(treeMaker.Ident(var.name));
        varList = varList.append(
            treeMaker.Select(
                treeMaker.Ident(
                    names.fromString(toLowerCaseFirstOne(classDecl.name.toString()))),var.name));
        // treeMaker.Apply 调用的是 JCMethodInvocation 
        JCTree.JCExpression expression = treeMaker.Apply(
            varType,memberAccess("java.util.Objects.equals"),varList);
        if (jcExpression==null){
            jcExpression = expression;
        }else {
            jcExpression = treeMaker.Binary(JCTree.Tag.AND,jcExpression,expression);
        }
    }
    JCTree.JCStatement jcStatement = treeMaker.Return(jcExpression);
    jcStatements = jcStatements.append(jcStatement);
    JCTree.JCBlock jcBlock = treeMaker.Block(0,jcStatements);

    JCTree.JCExpression defaultValue = null;
    JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(jcModifiers,methodName,
                                                           retrunType,jcTypeParameters,
                                                           variableDecls,throwableList,
                                                           jcBlock,defaultValue);
    return jcMethodDecl;
}

最后整个语法树生成代码的测试样例代码如下：

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package com.demo;

import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.TypeTag;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.tree.TreeTranslator;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.Name;
import com.sun.tools.javac.util.Names;

import javax.annotation.processing.Messager;

public class BeanTreeTranslator extends TreeTranslator {

    Messager messager;
    TreeMaker treeMaker;
    Names names;
    
    public BeanTreeTranslator(TreeMaker treeMaker,Messager messager,Names names) {
        this.treeMaker = treeMaker;
        this.messager = messager;
        this.names = names;
    }

    @Override
    public void visitBlock(JCTree.JCBlock jcBlock) {
        super.visitBlock(jcBlock);
    }

    @Override
    public void visitClassDef(JCTree.JCClassDecl jcClassDecl) {
        super.visitClassDef(jcClassDecl);
        List<JCTree> jcTreeList = jcClassDecl.defs;
        for (JCTree jcTree : jcClassDecl.defs){
            if (jcTree instanceof JCTree.JCVariableDecl){
                JCTree.JCVariableDecl jcVariableDecl = (JCTree.JCVariableDecl) jcTree;
                jcClassDecl.defs = jcClassDecl.defs.append(makeGetterMethod(jcVariableDecl));
                jcClassDecl.defs = jcClassDecl.defs.append(makeSetterMethod(jcVariableDecl));
            }
        }
        // toString 方法
        JCTree.JCMethodDecl toStringMethod = makeToStringMethod(jcClassDecl);
        jcClassDecl.defs = jcClassDecl.defs.append(toStringMethod);
        // hash 方法
        JCTree.JCMethodDecl hashMethod = makeHashMethodDecl(jcClassDecl);
        jcClassDecl.defs = jcClassDecl.defs.append(hashMethod);
        // equal 方法
        JCTree.JCMethodDecl equalMethod = makeEqualsMethod(jcClassDecl);
        jcClassDecl.defs = jcClassDecl.defs.append(equalMethod);
    }

    /**
     * 生成Getter 方法
     * @param jcVariableDecl
     * @return
     */
    public JCTree.JCMethodDecl makeGetterMethod(JCTree.JCVariableDecl jcVariableDecl){
        JCTree.JCModifiers modifiers = treeMaker.Modifiers(Flags.PUBLIC);
        JCTree.JCExpression returnType = jcVariableDecl.vartype;
        // 方法名
        Name methodName = getGetterMethod(jcVariableDecl);
        // 构建语句
        JCTree.JCStatement statement = treeMaker.Return(
                treeMaker.Select(
                        treeMaker.Ident(
                                names.fromString("this")),jcVariableDecl.name));

        List<JCTree.JCStatement> statementList = List.nil();
        statementList = statementList.append(statement);
        // 构建代码块
        JCTree.JCBlock jcBlock = treeMaker.Block(0,statementList);
        // 泛型参数列表
        List<JCTree.JCTypeParameter> typeParameters = List.nil();
        // 参数类型
        List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
        // 异常抛出列表
        List<JCTree.JCExpression> throwsClauses  = List.nil();
        //非自定义注解类中的方法，defaultValue为null
        JCTree.JCExpression defaultValue = null;

        JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(modifiers,
                                                               methodName,returnType,typeParameters,
                jcVariableDeclList,throwsClauses,jcBlock,defaultValue);
        return jcMethodDecl;

    }


    /**
     * 生成 Setter 方法
     * @param jcVariableDecl
     * @return
     */
    public JCTree.JCMethodDecl makeSetterMethod(JCTree.JCVariableDecl jcVariableDecl){
        JCTree.JCModifiers modifiers = treeMaker.Modifiers(Flags.PUBLIC);
        // 返回类型
        JCTree.JCExpression returnType = treeMaker.TypeIdent(TypeTag.VOID);
        // 方法名称
        Name methodName = getSetterMethod(jcVariableDecl);

        // 参数
        List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
        JCTree.JCVariableDecl param = treeMaker.VarDef(treeMaker.Modifiers(Flags.PARAMETER),
                                                       jcVariableDecl.name,
                                                       jcVariableDecl.vartype,null);
        param.pos = jcVariableDecl.pos; //设置形参这一句不能少，不然会编译报错(java.lang.AssertionError: Value of x -1)
        jcVariableDeclList = jcVariableDeclList.append(param);

        // 构建语句  //this.xxx = xxx;  setter方法中的赋值语句
        JCTree.JCStatement statement = treeMaker.Exec(
                treeMaker.Assign(
                        treeMaker.Select(treeMaker.Ident(
                            names.fromString("this")),jcVariableDecl.name),
                        treeMaker.Ident(param.name)));
        List<JCTree.JCStatement> statementList = List.nil();
        statementList = statementList.append(statement);

        JCTree.JCBlock jcBlock = treeMaker.Block(0,statementList);
        // 泛型参数
        List<JCTree.JCTypeParameter> typeParameters = List.nil();
        // 异常抛出列表
        List<JCTree.JCExpression> throwsClauses = List.nil();
        JCTree.JCExpression defaultValue = null;//非自定义注解类中的方法，defaultValue为null

        // 构建settter 方法
        JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(modifiers,methodName,returnType,
                typeParameters,jcVariableDeclList,throwsClauses,jcBlock,defaultValue);
        return jcMethodDecl;
    }


    /**
     * 生成 toString 方法
     * @param jcClassDecl
     * @return
     */
    public JCTree.JCMethodDecl makeToStringMethod(JCTree.JCClassDecl jcClassDecl){

        List<JCTree.JCVariableDecl> vars = List.nil();
        List<JCTree> jcTreeList = jcClassDecl.defs;
        for (JCTree jcTree: jcTreeList){
            if (jcTree instanceof JCTree.JCVariableDecl){
                JCTree.JCVariableDecl var = (JCTree.JCVariableDecl) jcTree;
                vars = vars.append(var);
            }
        }

        List<JCTree.JCAnnotation> jcAnnotationList = List.nil();
        // 方法注解
        JCTree.JCAnnotation jcAnnotation = treeMaker.Annotation(
            memberAccess("java.lang.Override"),List.nil());
        jcAnnotationList = jcAnnotationList.append(jcAnnotation);
        JCTree.JCModifiers jcModifiers = treeMaker.Modifiers(Flags.PUBLIC,jcAnnotationList); // 方法修饰词
        JCTree.JCExpression returnType = memberAccess("java.lang.String"); // 返回类型
        Name name = names.fromString("toString"); // 方法名

        JCTree.JCExpression jcExpression = treeMaker.Literal(jcClassDecl.name + "{");
        for (int i=0; i<vars.size(); i++){
            JCTree.JCVariableDecl var = vars.get(i);
            if (i!=0){
                jcExpression = treeMaker.Binary(
                    JCTree.Tag.PLUS,jcExpression,treeMaker.Literal("," + var.name.toString()+"="));
            }else {
                jcExpression = treeMaker.Binary(
                    JCTree.Tag.PLUS,jcExpression,treeMaker.Literal(var.name.toString()+"="));
            }

            if (var.vartype.toString().contains("String")){
                jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Literal("'"));
            }
            jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Ident(var.name));
            if (var.vartype.toString().contains("String")){
                jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Literal("'"));
            }
        }
        jcExpression = treeMaker.Binary(JCTree.Tag.PLUS,jcExpression,treeMaker.Literal("}"));

        JCTree.JCStatement jcStatement = treeMaker.Return(jcExpression);
        List<JCTree.JCStatement> statementList = List.nil();
        statementList = statementList.append(jcStatement);
        JCTree.JCBlock jcBlock = treeMaker.Block(0,statementList);
        // 参数列表
        List<JCTree.JCVariableDecl> variableDecls = List.nil();
        // 形参列表
        List<JCTree.JCTypeParameter> jcTypeParameters = List.nil();
        // 异常列表
        List<JCTree.JCExpression> throwableList = List.nil();
        JCTree.JCExpression defaultValue = null;

        JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(jcModifiers,
                                                               name,returnType,
                                                               jcTypeParameters,
                                                               variableDecls,
                                                               throwableList,jcBlock,defaultValue);
        return jcMethodDecl;
    }

    /**
     * 生成 hash 方法
     * @param classDecl
     * @return
     */
    public JCTree.JCMethodDecl makeHashMethodDecl(JCTree.JCClassDecl classDecl){
        List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
        List<JCTree> jcTreeList = classDecl.defs;
        for (JCTree jcTree : jcTreeList){
            if (jcTree instanceof JCTree.JCVariableDecl){
                JCTree.JCVariableDecl jcVariableDecl = (JCTree.JCVariableDecl) jcTree;
                jcVariableDeclList = jcVariableDeclList.append(jcVariableDecl);
            }
        }

        // Override 方法注解
        JCTree.JCAnnotation jcAnnotation = treeMaker.Annotation(
            memberAccess("java.lang.Override"),List.nil());
        List<JCTree.JCAnnotation> jcAnnotationList = List.nil();
        jcAnnotationList = jcAnnotationList.append(jcAnnotation);

        // 修饰方法关键字
        JCTree.JCModifiers jcModifiers = treeMaker.Modifiers(Flags.PUBLIC,jcAnnotationList);
        // 返回类型
        JCTree.JCExpression returnType = treeMaker.TypeIdent(TypeTag.INT);
        // 方法名称
        Name methodName = names.fromString("hashCode");
        // 异常
        List<JCTree.JCExpression> throwableList = List.nil();
        // 方法体
        List<JCTree.JCExpression> var1 = List.nil();
        List<JCTree.JCExpression> var2 = List.nil();

        for (JCTree.JCVariableDecl jcVariableDecl : jcVariableDeclList){
            //var1 = var1.append(typeTranslator(jcVariableDecl.vartype));
            var2 = var2.append(treeMaker.Ident(jcVariableDecl.name));
        }

        JCTree.JCExpression jcExpression = treeMaker.Apply(var1,
                                                           memberAccess("java.util.Objects.hash"),
                                                           var2);
        JCTree.JCStatement jcStatement = treeMaker.Return(jcExpression);
        List<JCTree.JCStatement> jcStatementList = List.nil();
        jcStatementList = jcStatementList.append(jcStatement);

        JCTree.JCBlock jcBlock = treeMaker.Block(0,jcStatementList);

        // 泛型变量
        List<JCTree.JCTypeParameter> jcTypeParameterList = List.nil();
        // 变量列表
        List<JCTree.JCVariableDecl> variableDeclList = List.nil();

        //
        JCTree.JCExpression defaultValue = null;

        JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(jcModifiers,
                                                               methodName,
                                                               returnType,jcTypeParameterList,
                variableDeclList,throwableList,jcBlock,defaultValue);
        return jcMethodDecl;
    }

    /**
     * 生成 equal 方法
     * @param classDecl
     * @return
     */
    public JCTree.JCMethodDecl makeEqualsMethod(JCTree.JCClassDecl classDecl){

        JCTree.JCExpression extend =  classDecl.extending;
        // 提取类中定义的变量
        List<JCTree> jcTreeList = classDecl.defs;
        List<JCTree.JCVariableDecl> jcVariableDeclList = List.nil();
        for (JCTree jcTree : jcTreeList){
            if (jcTree instanceof JCTree.JCVariableDecl){
                JCTree.JCVariableDecl var = (JCTree.JCVariableDecl) jcTree;
                jcVariableDeclList = jcVariableDeclList.append(var);
            }
        }
        // 方法注解
        JCTree.JCAnnotation jcAnnotation = treeMaker.Annotation(
            memberAccess("java.lang.Override"),List.nil());
        List<JCTree.JCAnnotation> jcAnnotationList = List.nil();
        jcAnnotationList = jcAnnotationList.append(jcAnnotation);
        // 方法关键修饰
        JCTree.JCModifiers jcModifiers = treeMaker.Modifiers(Flags.PUBLIC,jcAnnotationList);
        // 返回类型
        JCTree.JCExpression retrunType = treeMaker.TypeIdent(TypeTag.BOOLEAN);
        // 方法名称
        Name methodName = names.fromString("equals");
        // 泛型参数
        List<JCTree.JCTypeParameter> jcTypeParameters = List.nil();
        // 参数列表
        List<JCTree.JCVariableDecl> variableDecls = List.nil();
        JCTree.JCVariableDecl param = treeMaker.VarDef(treeMaker.Modifiers(Flags.PARAMETER),
                names.fromString("o"),memberAccess("java.lang.Object"),null);
        param.pos = classDecl.pos;
        variableDecls = variableDecls.append(param);
        // 异常列表
        List<JCTree.JCExpression> throwableList = List.nil();
        // 开始构建方法体
        //if (this == o) return true;
        List<JCTree.JCStatement> jcStatements = List.nil();
        JCTree.JCIf seqzero = treeMaker.If(treeMaker.Binary(
            JCTree.Tag.EQ,
            treeMaker.Ident(names.fromString("this")),
            treeMaker.Ident(names.fromString("o")))
                ,treeMaker.Return(treeMaker.Literal(true)),null);
        jcStatements = jcStatements.append(seqzero);

        // if (o == null || getClass() != o.getClass()) return false;
        JCTree.JCExpression getClassEqCondition = treeMaker.Apply(List.nil(),
                                                                  treeMaker.Select(
                                                                      treeMaker.Ident
                                                                      (names.fromString("this")),
                                                                      names.fromString("getClass")),
                                                                  List.nil());
        JCTree.JCExpression vargetClassEqCondition = treeMaker.Apply(List.nil(),
                                                                     treeMaker.Select(
                                                                         treeMaker.Ident(
                                                                             names.fromString("o")),
                                                                         names.fromString("getClass")),
                                                                     List.nil());

        JCTree.JCIf seqone = treeMaker.If(treeMaker.Binary(JCTree.Tag.OR
                ,treeMaker.Binary(JCTree.Tag.EQ,
                                  treeMaker.Ident(
                                      names.fromString("o")),treeMaker.Literal(TypeTag.BOT,null))
                ,treeMaker.Binary(JCTree.Tag.NE,getClassEqCondition,vargetClassEqCondition))
                ,treeMaker.Return(treeMaker.Literal(false)),null);
               
        jcStatements = jcStatements.append(seqone);


        // BeanTreeTranslator that = (BeanTreeTranslator) o;
        JCTree.JCVariableDecl jcVariableDecl = treeMaker.VarDef(treeMaker.Modifiers(0),
                                                                names.fromString(
                                                                    toLowerCaseFirstOne(
                                                                        classDecl.name.toString()))
                ,treeMaker.Ident(classDecl.name)
                ,treeMaker.TypeCast(treeMaker.Ident(classDecl.name),
                                    treeMaker.Ident(names.fromString("o"))) );
        jcStatements = jcStatements.append(jcVariableDecl);

        // return Objects.equals(messager, that.messager) &&
        //                Objects.equals(treeMaker, that.treeMaker) &&
        //                Objects.equals(names, that.names) &&
        //                Objects.equals(tep, that.tep);
        JCTree.JCExpression jcExpression = null;
        for (JCTree.JCVariableDecl var : jcVariableDeclList){
            List<JCTree.JCExpression> varType = List.nil();
            List<JCTree.JCExpression> varList = List.nil();

            //varType = varType.append(var.vartype);
            varList = varList.append(treeMaker.Ident(var.name));
            varList = varList.append(treeMaker.Select(
                treeMaker.Ident(names.fromString(
                    toLowerCaseFirstOne(classDecl.name.toString()))),var.name));
            JCTree.JCExpression expression = treeMaker.Apply(varType,
                                                             memberAccess("java.util.Objects.equals"),
                                                             varList);
            if (jcExpression==null){
                jcExpression = expression;
            }else {
                jcExpression = treeMaker.Binary(JCTree.Tag.AND,jcExpression,expression);
            }
        }
        JCTree.JCStatement jcStatement = treeMaker.Return(jcExpression);
        jcStatements = jcStatements.append(jcStatement);
        JCTree.JCBlock jcBlock = treeMaker.Block(0,jcStatements);

        JCTree.JCExpression defaultValue = null;
        JCTree.JCMethodDecl jcMethodDecl = treeMaker.MethodDef(jcModifiers,methodName,
                                                               retrunType,
                                                               jcTypeParameters,
                                                               variableDecls,
                                                               throwableList,jcBlock,defaultValue);
        return jcMethodDecl;
    }

    //传入一个类的全路径名，获取对应类的JCIdent
    private JCTree.JCExpression memberAccess(String components) {
        String[] componentArray = components.split("\\.");
        JCTree.JCExpression expr = treeMaker.Ident(names.fromString(componentArray[0]));
        for (int i = 1; i < componentArray.length; i++) {
            expr = treeMaker.Select(expr, names.fromString(componentArray[i]));
        }
        return expr;
    }
    //装箱
    private JCTree.JCExpression typeTranslator(JCTree.JCExpression type){
        if (type.toString().equals("int")){
            type = memberAccess("java.lang.Integer");
        }else if (type.toString().equals("long")){
            type = memberAccess("java.lang.Long");
        }else if(type.toString().equals("short")){
            type = memberAccess("java.lang.Short");
        }else if(type.toString().equals("double")){
            type = memberAccess("java.lang.Double");
        }else if(type.toString().equals("boolean")){
            type = memberAccess("java.lang.Boolean");
        }else if(type.toString().equals("float")){
            type = memberAccess("java.lang.Float");
        }else if(type.toString().equals("char")){
            type = memberAccess("java.lang.Character");
        }else if(type.toString().equals("byte")){
            type = memberAccess("java.lang.Byte");
        }
        return type;
    }
    
    //首字母转小写
    public static String toLowerCaseFirstOne(String s){
        if(Character.isLowerCase(s.charAt(0)))
            return s;
        else
            return (new StringBuilder()).append(Character.toLowerCase(s.charAt(0)))
            .append(s.substring(1)).toString();
    }

    /**
     * 根据变量名称生成 getXxx 方法名
     * @param jcVariableDecl
     * @return
     */
    public Name getGetterMethod(JCTree.JCVariableDecl jcVariableDecl){
        String varName = jcVariableDecl.name.toString();
        Name methodName = names.fromString("get"+varName.substring(0,1).toUpperCase()+
                                           varName.substring(1,varName.length()));
        return methodName;
    }

    /**
     * 根据变量名称生成 setXxx 方法名称
     * @param jcVariableDecl
     * @return
     */
    public Name getSetterMethod(JCTree.JCVariableDecl jcVariableDecl){
        String varName = jcVariableDecl.name.toString();
        Name methodName = names.fromString("set"+varName.substring(0,1).toUpperCase()+
                                           varName.substring(1,varName.length()));
        return methodName;
    }
}

最后的编译生成的字节码结果如下：

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@Service
public class DemoC {
    String var1;
    String var2;
    Integer tempInt;
    Double tempDouble;
    DemoA demoA;
    int temp;

    public DemoC() {
    }

    public String getVar1() {
        return this.var1;
    }

    public void setVar1(String var1) {
        this.var1 = var1;
    }

    public String getVar2() {
        return this.var2;
    }

    public void setVar2(String var2) {
        this.var2 = var2;
    }

    public Integer getTempInt() {
        return this.tempInt;
    }

    public void setTempInt(Integer tempInt) {
        this.tempInt = tempInt;
    }

    public Double getTempDouble() {
        return this.tempDouble;
    }

    public void setTempDouble(Double tempDouble) {
        this.tempDouble = tempDouble;
    }

    public DemoA getDemoA() {
        return this.demoA;
    }

    public void setDemoA(DemoA demoA) {
        this.demoA = demoA;
    }

    public int getTemp() {
        return this.temp;
    }

    public void setTemp(int temp) {
        this.temp = temp;
    }

    public String toString() {
        return "DemoC{var1='" + this.var1 + "'" + ",var2=" + "'" + this.var2 + "'" + ",tempInt=" + this.tempInt + ",tempDouble=" + this.tempDouble + ",demoA=" + this.demoA + ",temp=" + this.temp + "}";
    }

    public int hashCode() {
        return Objects.hash(new Object[]{this.var1, this.var2, this.tempInt, this.tempDouble, this.demoA, this.temp});
    }

    public boolean equals(Object o) {
        if (this == o) {
            return true;
        } else if (o != null && this.getClass() == o.getClass()) {
            DemoC demoC = (DemoC)o;
            return Objects.equals(this.var1, demoC.var1) && Objects.equals(this.var2, demoC.var2) && Objects.equals(this.tempInt, demoC.tempInt) && Objects.equals(this.tempDouble, demoC.tempDouble) && Objects.equals(this.demoA, demoC.demoA) && Objects.equals(this.temp, demoC.temp);
        } else {
            return false;
        }
    }
赏

谢谢你请我吃糖果

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tag:

    缺失模块。
    1、请确保node版本大于6.2
    2、在博客根目录（注意不是yilia根目录）执行以下命令：
    npm i hexo-generator-json-content --save

    3、在根目录_config.yml里添加配置： 

      jsonContent:
    meta: false
    pages: false
    posts:
      title: true
      date: true
      path: true
      text: false
      raw: false
      content: false
      slug: false
      updated: false
      comments: false
      link: false
      permalink: false
      excerpt: false
      categories: false
      tags: true

很惭愧<br><br>只做了一点微小的工作<br>谢谢大家