java反编译获取源码

最近在研究反射，想做一个东西，把运行的java程序饭编译（Decompile）成.java文件。现思路如下：

1.写出程序反编译一个类

2.将所有类反编译

3.java代码注入一个正在运行的java程序中

现已实现第一步：

代码如下：

//这是一个要反编译的类
public class Reflect {
    private int num;
    public int getNum() {
        return num;
    }
    public void setNum(int num) {
        this.num = num;
    }
    public String getString() {
        return string;
    }
    public void setString(String string) {
        this.string = string;
    }
    private String string;
    public void printProperty(){
        System.out.println(getNum());
        System.out.println(string);
    }
    public void println(String s){
        System.out.println(s);
    }
}

//实现反编译的类，现在可以判断具体有哪些方法，但是方法里面的具体细节还不能输出
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Parameter;


public class Decompile {
    private Class<?> c;        
    private Reflect reflect;
    private String className;
    public Decompile(String className){
        try {
            this.className = className;
            c = Class.forName(className);
            reflect=(Reflect)c.newInstance();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    //获得构造方法
    public void getConstructFuntion(){
        Constructor[] constructors = c.getConstructors();
        for(Constructor constructor:constructors){
            System.out.println(
                    Modifier.toString(constructor.getModifiers())
                    +" "
                    +constructor.getName()
                    +"("
                    +getParameter(constructor)
                    +"){}");
            
        }
    }
    //获得类信息
    public void getClassInfo(){
        try {
            System.out.println(
                    Modifier.toString(c.getModifiers())
                    +" class"
                    +className
                    +"{");
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    //获得类属性信息
    public void getProperty(){
        Field[] fields = c.getDeclaredFields();
        for(Field field:fields){
            field.setAccessible(true);
            try {
                System.out.println(
                        Modifier.toString(field.getModifiers())
                        +" "
                        +field.getType().getSimpleName()
                        +" "
                        +field.getName()
                        +" = "
                        +field.get(reflect)
                        +";");
            } catch (IllegalArgumentException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    //获得类方法信息
    public void getFuntion(){
        Method[] methods=c.getDeclaredMethods();
        for(Method method:methods){
            System.out.println(
                    Modifier.toString(method.getModifiers())
                    +" "
                    +method.getReturnType().getSimpleName()
                    +" "
                    +method.getName().toString()
                    +"("
                    +getParameter(method)
                    +"){}");
        }
    }
    //获得参数字符串
    public String getParameter(Object obj){
        Parameter[] parameters=null;
        if("Method".equals(obj.getClass().getSimpleName())){
            parameters = ((Method)obj).getParameters();
        }
        else{
            parameters = ((Constructor)obj).getParameters();
        }
        StringBuffer sb = new StringBuffer();
        int count = 0;
        for(Parameter parameter:parameters){
            if(count!=0){
                sb.append(",");
            }
            sb.append(parameter.getType().getSimpleName()
                    +" "
                    +parameter.getName().toString());
            count++;
        }
        return sb.toString();
    }
}

//测试代码
public class TestReflect {

    public static void main(String[] args) {
        Decompile decompile=new Decompile("Reflect");
        decompile.getClassInfo();
        decompile.getConstructFuntion();
        decompile.getProperty();
        decompile.getFuntion();
        System.out.println("}");
    }
}

下次再完成剩下