import java.io.FileOutputStream;

import org.objectweb.asm.AnnotationVisitor;

import org.objectweb.asm.ClassWriter;

import org.objectweb.asm.FieldVisitor;

import org.objectweb.asm.MethodVisitor;

import org.objectweb.asm.Opcodes;

public class BeanTest2 extends ClassLoader implements Opcodes{

    public static void main(String []args) throws Exception

    {

        ClassWriter cw = new ClassWriter(0);

        //类名

        cw.visit(V1_7, ACC_PUBLIC, "com/xxx/model/_766ComLeakInfo", null, "com/xxx/model/LeakInfo", null);

        //注释

        AnnotationVisitor  av = cw.visitAnnotation("Lorg/springframework/data/mongodb/core/mapping/Document;", true);

        //注释参数

        av.visit("collection", "uc_members");

        av.visitEnd();

        //构造函数

        MethodVisitor mw = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null,null);

        mw.visitVarInsn(ALOAD, 0);

        mw.visitMethodInsn(INVOKESPECIAL, "com/xxx/model/LeakInfo", "<init>", "()V");

        mw.visitInsn(RETURN);

        mw.visitMaxs(1, 1);

        mw.visitEnd();

        //字段

        FieldVisitor  fv = cw.visitField(ACC_PUBLIC, "description", "Ljava/lang/String;", null, null);

        fv.visitEnd();

        byte[] code = cw.toByteArray();

         //将二进制流写到本地磁盘上

       FileOutputStream fos = new FileOutputStream("E:/asm/bin/com/xxx/model/_766ComLeakInfo.class");

       fos.write(code);

       fos.close();

       BeanTest2 loader = new BeanTest2();

        Class<?> clazz = loader.defineClass(null, code, 0, code.length);

        Object beanObj = clazz.getConstructor().newInstance();

        clazz.getField("description").set(beanObj, "Adobe客户信息泄露!");

        String nameString = (String) clazz.getField("description").get(beanObj);

        System.out.println("filed value : " + nameString);

    }

}

import java.io.Serializable;

import org.springframework.data.mongodb.core.mapping.Document;

@SuppressWarnings("serial")

@Document

public class LeakInfo implements Serializable{

    //@Id

    long id;

    String type;

    String username;

    String email;

    String password;

    String source;

    String description;

    public long getId() {

        return id;

    }

    public void setId(long id) {

        this.id = id;

    }

    public String getType() {

        return type;

    }

    public void setType(String type) {

        this.type = type;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getEmail() {

        return email;

    }

    public void setEmail(String email) {

        this.email = email;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

    public String getSource() {

        return source;

    }

    public void setSource(String source) {

        this.source = source;

    }

    public String getDescription() {

        return description;

    }

    public void setDescription(String description) {

        this.description = description;

    }

}

import org.springframework.data.mongodb.core.mapping.*;

@Document(collection = "uc_members")

public class _766ComLeakInfo extends LeakInfo

{

    public String description;

}