javaassist创建对象

第一步：maven添加jar (https://mvnrepository.com/artifact/org.javassist/javassist/3.28.0-GA)

<dependency>
   <groupId>org.javassist</groupId>
   <artifactId>javassist</artifactId>
   <version>3.28.0-GA</version>
</dependency>

第二步：
ppublic class TestAssist {
    public static void main(String[] args) throws CannotCompileException, IOException, NotFoundException, InvocationTargetException, IllegalAccessException, InstantiationException, NoSuchMethodException {
        // 获取默认的类池
        ClassPool pool = ClassPool.getDefault();

        // 在类池设置类
        CtClass cc = pool.makeClass("com.dong.assist.TestUser");

        // 设置 类的属性
        CtField name = CtField.make("private String name;",cc);
        CtField age = CtField.make("private int age;",cc);

        cc.addField(name);
        cc.addField(age);

        // 设置类的方法
        CtMethod setAll = CtMethod.make("public void setName(String name,int age){"
                +"this.name = name; this.age = age;}",cc);
        CtMethod getName = CtMethod.make("public String getName(){" +
                "return this.name;}",cc);
        cc.addMethod(setAll);
        cc.addMethod(getName);

        // 设置类的构造器（两个参数）
        CtConstructor constructor = new CtConstructor(new CtClass[]{pool.get("java.lang.String"),CtClass.intType},cc);
        // 构造器体，里面的参数用$1,$2代替
        constructor.setBody("{this.name = $1;this.age=$2;}");
        cc.addConstructor(constructor);

        // 保存
        cc.writeFile("D:\\TestUser");
        System.out.println("ok");

        // 反射，创建对象
        Class clazz = cc.toClass();
        Constructor constructor1 = clazz.getConstructor(String.class, int.class);
        constructor1.setAccessible(true);
        Object obj = constructor1.newInstance(new Object[]{"hello",50});


        Method getNameMethod = clazz.getDeclaredMethod("getName");
        System.out.println(getNameMethod.invoke(obj));

        Method setName = clazz.getDeclaredMethod("setName",String.class,int.class);
        setName.invoke(obj,"maohuidong",30);
        System.out.println(getNameMethod.invoke(obj));
    }
}

第三步：github下载xjad，反编译生成的TestUser (https://github.com/aspeople/xjad)

 

参考：https://blog.csdn.net/mousebaby808/article/details/37696371

https://www.bbsmax.com/A/Gkz10Me2dR/