动态反射代理实现机制两例代码比较(二)

      动态反射代理实现机制两例代码比较，最近研究设计模式，略作深入分析基于JDK1.3以来的Java动态反射代理，也结合最新的JDK1.6版本以上的新特性进行比较，业界主要有CGLIB、ASM等技术实现生成字节码。

      通常我们使用反射代理这种统一处理方式针对一致日志、事务、权限、监控、拦截等这种具有切面点的场景进行一系列的自动处理，减轻程序员的代码编写量，提升代码的耦合度，适当提升代码编写质量，对系统架构的扩展性进一步加强。此处放在这里做一个参考比较，学习使用，抛砖引玉，以资共享......

由于时间紧迫，先写一个简单日后再完善......

第二种实现代码如下(基于JDK1.6以上的自带新特性)：

被代理方法的接口类 Vehicleable.java：

/**
 * @author Dennis Zhao
 * @createdTime：Mar 29, 2013
 */
public interface Vehicleable extends java.io.Serializable {
    void run();
    void run(Car car);
    void run(Car car, MotoCar c);
}

 

被代理方法的接口实现类 Vehicle.java：

import java.util.Random;

/**
 * @author Dennis Zhao
 * @createdTime：Mar 29, 2013
 */
public class Vehicle implements Vehicleable {

    private static final long serialVersionUID = 7633089691765059657L;

    @Override
    public void run() {
        System.out.println("Automatic Moving...");
        try {
            Thread.sleep(new Random().nextInt(100));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run(Car car) {
        String name = Car.class.getName();
        System.out.println(name.substring(name.lastIndexOf(".") + 1) +  " Moving...");
        System.out.println("car name == " + car.getName() );
        System.out.println("car color == " + car.getColor() );
        System.out.println("car age == " + car.getAge() );
        try {
            Thread.sleep(new Random().nextInt(100));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run(Car car, MotoCar c) {
        String name = Car.class.getName();
        String name1 = MotoCar.class.getName();
        System.out.println(name.substring(name.lastIndexOf(".") + 1)
            + " and " + name1.substring(name1.lastIndexOf(".") + 1) + " Moving...");
        System.out.println("car name == " + car.getName() );
        System.out.println("car color == " + car.getColor() );
        System.out.println("car age == " + car.getAge() );
        System.out.println("motocar color == " + c.getColor() );
        System.out.println("motocar name == " + c.getName() );
        System.out.println("motocar age == " + c.getAge() );
        try {
            Thread.sleep(new Random().nextInt(100));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

 

提供两个测试用的Javabea类Car.java, MotoCar.java

/**
 * @author Dennis Zhao
 * @createdTime：Mar 29, 2013
 */
public class Car implements java.io.Serializable {

    private static final long serialVersionUID = 1L;
    private String name;
    private String color;
    private int age;

    public String getName() {
        return name;
    }

    public Car setName(String name) {
        this.name = name;
        return this;
    }

    public String getColor() {
        return color;
    }

    public Car setColor(String color) {
        this.color = color;
        return this;
    }

    public int getAge() {
        return age;
    }

    public Car setAge(int age) {
        this.age = age;
        return this;
    }
}

 

MotoCar.java

/**
 * @author Dennis Zhao
 * @createdTime：Mar 29, 2013
 */
public class MotoCar implements java.io.Serializable {
    private static final long serialVersionUID = 11L;
    private String name;
    private String color;
    private int age;

    public String getName() {
        return name;
    }

    public MotoCar setName(String name) {
        this.name = name;
        return this;
    }

    public String getColor() {
        return color;
    }

    public MotoCar setColor(String color) {
        this.color = color;
        return this;
    }

    public int getAge() {
        return age;
    }

    public MotoCar setAge(int age) {
        this.age = age;
        return this;
    }
}

 

自定义一个模拟JDK接口类InvocationHandler.java

/**
 * 模拟 JDK InvocationHandler处理类
 * @author Dennis Zhao
 * @createdTime：Mar 29, 2013
 */
public interface InvocationHandler extends java.io.Serializable {
    public void invoke(Object o, Method m, Object... obj);
}

 

 接口类InvocationHandler的实现类LogHandler.java

import java.lang.reflect.Method;

/**
 * 模拟日志包装处理类
 * @author Dennis Zhao
 * @createdTime：Mar 29, 2013
 */
public class LogHandler implements InvocationHandler{

    private static final long serialVersionUID = -9124608101609510202L;
    private Object target;

    public LogHandler(Object target) {
        super();
        this.target = target;
    }

    @Override
    public void invoke(Object o, Method m, Object... obj) {
        long start = System.currentTimeMillis();
        System.out.println("正式的方法 log :" + start);
        //System.out.println(o.getClass().getName());
        try {
            m.invoke(target, obj);
        } catch (Exception e) {
            e.printStackTrace();
        }
        long end = System.currentTimeMillis();
        System.out.println("运行 时间 log :" + (end-start));
    }
}

 

生成隐藏动态代理类HiddenProxy.java

import java.io.File;
import java.io.FileWriter;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import javax.tools.JavaCompiler;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
import javax.tools.JavaCompiler.CompilationTask;


/**
 * 隐藏代理类，完全动态生成执行，自定义代码
 * @author Dennis Zhao
 * @createdTime：Mar 29, 2013
 */
public class HiddenProxy {

    @SuppressWarnings("unchecked")
    public static Object newProxyInstance(Class<?> interfaces, InvocationHandler h) throws Exception {
        StringBuffer methodStr = new StringBuffer("");
        String newLine = "\r\n";
        String curPath = System.getProperty("user.dir");
        String filePath = curPath + File.separator + "tmp" + File.separator;
        Method[] methods = interfaces.getMethods();
        for(Method m : methods) {
            StringBuffer sb = new StringBuffer("");m.getParameterTypes();
            StringBuffer sbp = new StringBuffer("");
            Class[] cs = m.getParameterTypes();
            for (Class c : cs) {
                String objName = c.getName();
                sb.append(objName).append(" ")
                  .append(objName.substring(objName.lastIndexOf(".") + 1).toLowerCase())
                  .append(",");
                sbp.append(sb.substring(sb.lastIndexOf(" ")+1));
            }
            String strParam = "";
            String param = "";
            if(sb.length() > 0) {
                strParam = sb.substring(0, sb.length() - 1);
                param = "new Object[]{"+ sbp.substring(0, sbp.length() - 1) + "}";
            } else {
                param = "new Object[]{}";
            }
            int len = m.getParameterTypes().length;
            methodStr.append(newLine).append("	@Override").append(newLine)
                 .append("	public void " + m.getName() + "(" + strParam + ") {" + newLine)
                 .append("		try {" + newLine )
                 .append("			System.out.println(\"自定义事务开始...\");" + newLine)
                 .append("			Method[] mds = " + interfaces.getName() + ".class.getMethods();").append(newLine)
                 .append("			for(Method m : mds) {").append(newLine)
                 .append("				if (m.getName().startsWith(\"" + m.getName() + "\")  && ")
                 .append(			len+"==m.getParameterTypes().length) {").append(newLine)
                 .append("					h.invoke(this, m, " + param + ");").append(newLine)
                 .append("					break;").append(newLine)
                 .append("				}").append(newLine)
                 .append("			}").append(newLine)
                 .append(            newLine )
                 .append("			System.out.println(\"自定义事务完毕。 \" );" + newLine )
                 .append("		} catch(Exception e) {").append(newLine)
                 .append("			e.printStackTrace();" + newLine )
                 .append("		}" + newLine )
                 .append("	}" + newLine) ;
        }

        StringBuffer src = new StringBuffer().append(
            "package com.pattern.proxy.aop.proxy;" +  newLine)
            .append("import java.lang.reflect.Method;" + newLine)
            .append("import com.pattern.proxy.aop.proxy.InvocationHandler;" + newLine)
            .append("public class MyProxy implements " + interfaces.getName() + "{" + newLine)
            .append("    InvocationHandler h;" + newLine)
            .append("    public MyProxy(InvocationHandler h) {" + newLine )
            .append("        this.h = h;" + newLine )
            .append("    }" + newLine )
            .append(methodStr + newLine )
            .append("}");
        String fileName = filePath +  "com" + File.separator +"pattern" + File.separator
            + "proxy" + File.separator +"aop" + File.separator +"proxy" + File.separator;
        File f = new File(fileName);
        f.mkdirs();
        fileName = fileName + "MyProxy.java";
        File f1 = new File(fileName);
        FileWriter fw = new FileWriter(f1);
        fw.write(src.toString());
        fw.flush();
        fw.close();

        //compile
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        StandardJavaFileManager fileMgr = compiler.getStandardFileManager(null, null, null);
        Iterable units = fileMgr.getJavaFileObjects(fileName);
        CompilationTask t = compiler.getTask(null, fileMgr, null, null, null, units);
        t.call();
        fileMgr.close();
        //load into memory and create an instance
        URL[] urls = new URL[] {new URL("file://" + filePath)};
        URLClassLoader ul = new URLClassLoader(urls);
        Class<?> c = ul.loadClass("com.pattern.proxy.aop.proxy.MyProxy");
        Constructor<?> ctr = c.getConstructor(InvocationHandler.class);
        Object m = ctr.newInstance(h);
        //System.out.println(m.getClass().getName());
        return m;
    }
}

 

最后测试类以及测试结果Test.java

/**
 * AOP模拟实现动态反射代理机制，基于 JDK1.6以上
 * @author Dennis zhaoxiaobo
 * @createdTime：Mar 29, 2013
 */
public class Test {
    public static void main(String[] args) throws Exception {
        Vehicle t = new Vehicle();
        InvocationHandler h = new LogHandler(t);
        Vehicleable m = (Vehicleable)HiddenProxy.newProxyInstance(Vehicleable.class, h);
        m.run();
        m.run(new Car().setName("abo car").setAge(12).setColor("black"));
        m.run(new Car().setName("my car").setAge(11).setColor("red"),
                new MotoCar().setColor("green").setName("Abo's motocar").setAge(100));

    }
}
////可以对任意的对象、任意的接口方法，实现任意的代理, 针对对象，注意(不支持基本数据类型)

/*
------------ 打印测试结果--------------

自定义事务开始...
正式的方法 log :1364539212298
Automatic Moving...
运行 时间 log :62
自定义事务完毕。
自定义事务开始...
正式的方法 log :1364539212360
Car Moving...
car name == abo car
car color == black
car age == 12
运行 时间 log :78
自定义事务完毕。
自定义事务开始...
正式的方法 log :1364539212438
Car and MotoCar Moving...
car name == my car
car color == red
car age == 11
motocar color == green
motocar name == Abo's motocar
motocar age == 100
运行 时间 log :110
自定义事务完毕。
*/

 

 指定生成了虚拟的Java类，帮我们做一些本应该由代理类来完成的工作。

 由于工作事情多，有时间再整理做一些文字性补充说明.....^_^