(原创)android 反射机制Demo

来源：互联网发布：php支付宝接口开发步骤编辑：程序博客网时间：2024/05/21 14:51

废话不多说，直接看项目，注释已够详细了。

1. 效果图

2. 实现类

MainActivity

package com.example.lainanzhou.filetest;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import java.io.File;import java.io.IOException;import java.io.RandomAccessFile;import java.lang.reflect.Constructor;import java.lang.reflect.Field;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.nio.channels.FileChannel;import java.util.Properties;public class MainActivity extends AppCompatActivity {    private static final String TAG = "MainActivity";    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);    }    public void write(View view) {        String fileName = getFilesDir().getAbsolutePath() + "/test1.txt";        byte[] bytes = new byte[8 * 1024 * 1024];        File file = new File(fileName);        RandomAccessFile raf;        try {            raf = new RandomAccessFile(file, "rw");            raf.write(bytes);// 写入占用8M空间的空白文件            raf.close();            Log.d("MainActivity", "File length: " + new File(fileName).length() / 1024 / 1024);        } catch (Exception e) {            e.printStackTrace();        }    }    public void read(View view) {        String fileName = getFilesDir().getAbsolutePath() + "/test1.txt";        Log.d("MainActivity", "File length: " + new File(fileName).length() / 1024 / 1024);        //        byte[] bytes = new byte[1024 * 1024];        String str = "aaa";        File file = new File(fileName);        RandomAccessFile raf;        try {            raf = new RandomAccessFile(file, "rw");            FileChannel fc = raf.getChannel();            //将文件大小截为0：清空文件内容            fc.truncate(0);            raf.write(str.getBytes());// 重新写入数据            raf.close();            Log.d("MainActivity", "File length: " + new File(fileName).length());        } catch (Exception e) {            e.printStackTrace();        }    }    /**     * 反射直接获取对应的包下的操作类进行set和get操作     *     * @param view     */    public void reflect(View view) {        try {            // 反射获取对应类            Class<?> demo = Class.forName("com.example.lainanzhou.filetest.ReflectBean");            // 使用该方式获取实例注意：构造函数必须有不带参的，不然会报： java.lang.InstantiationException            //            ReflectBean reflectBean = (ReflectBean) demo.newInstance();            //            reflectBean.setName("Joker");            //            reflectBean.setAge(20);            //            Log.d(TAG, " ReflectBean " + reflectBean.toString());            // 另外种方式可以不需要设置不带参构造函数            Constructor<?> cons[] = demo.getConstructors(); //取得全部的构造函数            ReflectBean reflectBean = (ReflectBean) cons[0].newInstance("Joker", 20);            // 两种方式同样可以设置参数            Log.d(TAG, " ReflectBean " + reflectBean.toString());            // 获取操作类实现类            Class<?> intes[] = demo.getInterfaces();            for (int i = 0; i < intes.length; i++) {                Log.d(TAG, " ReflectBean 实现接口：" + intes[i].getName());            }            //取得父类            Class<?> superclass = demo.getSuperclass();            Log.d(TAG, " ReflectBean 继承的父类为：   " + superclass.getName());            // 获取里面所有方法及返回类型            Method method[] = demo.getMethods();            for (int i = 0; i < method.length; ++i) {                Class<?> returnType = method[i].getReturnType();                //                Class<?> para[] = method[i].getParameterTypes();                //                int temp = method[i].getModifiers();                //                Log.d(TAG, " ReflectBean " + Modifier.toString(temp) + " ");                Log.d(TAG, " ReflectBean returnType" + " : " + returnType.getName());                Log.d(TAG, " ReflectBean method" + i + " : " + method[i].getName());                //                System.out.print("(");                //                for (int j = 0; j < para.length; ++j) {                //                    System.out.print(para[j].getName() + " " + "arg" + j);                //                    if (j < para.length - 1) {                //                        System.out.print(",");                //                    }                //                }            }            // 调用操作类中的方法: 后面是参数类型            Method testInterface = demo.getMethod("testInterface", String.class);            testInterface.invoke(reflectBean, "Joker from testInterface");// 后面是需要传入的数据            // 通过反射操作属性            Field field = demo.getDeclaredField("age");// 获取私有的属性            field.setAccessible(true);// 设置可操作属性            field.set(reflectBean, 21);// 设置属性值            Log.d(TAG, "操作属性" + field.get(reflectBean));        } catch (Exception e) {            Log.d(TAG, " Exception " + e.toString());            e.printStackTrace();        }    }    /**     * 通过类加载器获取对应操作类里面接口实现其方法     *     * @param v     */    public void getClassLoader(View v) {        MyInvocationHandler demo = new MyInvocationHandler();        ReflectInterface sub = (ReflectInterface) demo.bind(new ReflectBean("Joker", 22));        sub.testInterface("Joker from MyInvocationHandler");    }    /**     * 类加载构造器，需要实现InvocationHandler接口     */    class MyInvocationHandler implements InvocationHandler {        private Object obj = null;        public Object bind(Object obj) {            this.obj = obj;            return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj                    .getClass().getInterfaces(), this);        }        @Override        public Object invoke(Object proxy, Method method, Object[] args)                throws Throwable {            Object temp = method.invoke(this.obj, args);            return temp;        }    }    public void factory(View v) {        try {            Properties pro = FactoryManager.getPro(this);            ReflectInterface reflectInterface = FactoryManager.getInstance(pro.getProperty("one"));            if (reflectInterface != null) {                reflectInterface.testInterface("Joker from FactoryManager");            }        } catch (IOException e) {            e.printStackTrace();        }    }}

ReflectInterface

package com.example.lainanzhou.filetest;/** * @author Joker * @since 2016/9/21. */interface ReflectInterface {    void testInterface(String name);}

ReflectBean

package com.example.lainanzhou.filetest;import android.util.Log;/** * @author Joker * @since 2016/9/21. */public class ReflectBean extends ReflectSuper implements ReflectInterface {    private String name;    private int age;    //    public ReflectBean() {    //    }    public ReflectBean(String name, int age) {        this.name = name;        this.age = age;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    @Override    public String toString() {        return "ReflectBean{" +                "name='" + name + '\'' +                ", age=" + age +                '}';    }    @Override    public void testInterface(String name) {        Log.d("MainActivity", "testInterface: " + name);    }}

ReflectSuper

package com.example.lainanzhou.filetest;/** * @author Joker * @since 2016/9/21. */public class ReflectSuper {}

FactoryManager

package com.example.lainanzhou.filetest;import android.content.Context;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.util.Properties;/** * @author Joker * @since 2016/9/22. */public class FactoryManager {    public static ReflectInterface getInstance(String ClassName) {        ReflectInterface rfInterface = null;        try {            rfInterface = (ReflectInterface) Class.forName(ClassName).newInstance();        } catch (Exception e) {            e.printStackTrace();        }        return rfInterface;    }    /**     * 操作文件属性的方法     *     * @return     * @throws FileNotFoundException     * @throws IOException     */    public static Properties getPro(Context context) throws FileNotFoundException, IOException {        Properties pro = new Properties();        File f = new File(context.getFilesDir() + "/reflectInterface.properties");        if (f.exists()) {            pro.load(new FileInputStream(f));        } else {            pro.setProperty("one", "com.example.lainanzhou.filetest.ProduceOne");            pro.setProperty("two", "com.example.lainanzhou.filetest.ProduceTwo");            pro.store(new FileOutputStream(f), "REFLECTINTERFACE CLASS");        }        return pro;    }}

ProduceOne

package com.example.lainanzhou.filetest;import android.util.Log;/** * @author Joker * @since 2016/9/22. */public class ProduceOne implements ReflectInterface {    @Override    public void testInterface(String name) {        Log.d("ProduceOne", "ProduceOne: " + name);    }}

ProduceTwo

package com.example.lainanzhou.filetest;import android.util.Log;/** * @author Joker * @since 2016/9/22. */public class ProduceTwo implements ReflectInterface {    @Override    public void testInterface(String name) {        Log.d("ProduceTwo", "ProduceTwo: " + name);    }}

项目链接：

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