Reflect in Java

java反射的使用:

package com.test.struts2;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;

import com.opensymphony.module.sitemesh.util.ClassLoaderUtil;

public class TestReflect {

    private String userName;

    private String passWord;

    public String userNamePublic;

    public String passWordPublic;

    private ClassLoader classLoader;

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

        Class clazz = Class.forName("com.test.struts2.TestReflect");

        // 通过线程获取ClassLoder
        Class clazz1 = Thread.currentThread().getContextClassLoader()
                .loadClass("com.test.struts2.TestReflect");

        // 通过.class获取ClassLoder(TestReflect参数只可以使自己包中命名的类)
        Class clazz2 = TestReflect.class.getClassLoader().loadClass(
                "com.test.struts2.TestReflect");

        // Struts2中的ClassLoaderUtil类，对线程获取进行了分装
        Class clazz3 = ClassLoaderUtil.loadClass(
                "com.test.struts2.TestReflect", String.class);

        // 新建实例(newInstance建立)
        TestReflect testReflect = (TestReflect) clazz.newInstance();

        // 属性(所有的的属性)
        Field[] fields = clazz.getDeclaredFields();
        System.out.println("---------所有属性 ");
        for (Field field : fields) {
            System.out.println(field.getName());
        }

        // 属性(public的属性)
        System.out.println("---------public属性 ");
        Field[] fieldsPublic = clazz.getFields();
        for (Field field : fieldsPublic) {
            System.out.println("public属性: " + field.getName());
        }

        // 通过getXXX和setXXX方法访问八个基本类型的值
// 如果该属性类型是引用类型则直接使用get(Object obj)
        Field f = clazz.getDeclaredField("userName");
        testReflect.setUserName("Hello");
        System.out.println(f);
        f.setAccessible(true);
        f.set(testReflect, "111");
        System.out.println(testReflect.getUserName());
        System.out.println("调用了该方法：" + f.get(testReflect));

        System.out.println("---------所有方法 ");
        // 所有的方法
        Method[] methods = clazz.getDeclaredMethods();
        for (Method method : methods) {
            System.out.println(method.getName());
        }

        System.out.println("---------public方法 ");
        // public的方法
        Method[] methodsPublic = clazz.getDeclaredMethods();

        for (Method method : methodsPublic) {
            System.out.println("public方法: " + method.getName());
        }

        // 方法的调用
        for (Method method : methodsPublic) {
            System.out.println("调用了方法: " + method.getName());
            // method.invoke(obj, args);
        }

        System.out.println("---------构造器 ");
        // 构造器
        Constructor[] Constructors = clazz.getConstructors();
        for (Constructor constructor : Constructors) {
            System.out.println("构造器: " + constructor.getName());
        }

        if (testReflect instanceof TestReflect) {
            System.out.println("YES: 我是TestReflect实例变量");
        } else {
            System.out.println("YES: 我不是TestReflect实例变量");
        }

        // 通过构造器实例化(),默认构造器
        Constructor constructor = clazz.getConstructor(new Class[] {});
        testReflect = (TestReflect) constructor.newInstance();
        if (testReflect instanceof TestReflect) {
            System.out.println("YES: 我是TestReflect实例变量");
        } else {
            System.out.println("YES: 我不是TestReflect实例变量");
        }

        // 通过构造器实例化(),默认构造器
        Constructor constructorss = clazz.getConstructor(new Class[] {
                String.class, String.class, String.class, String.class });
        testReflect = (TestReflect) constructorss.newInstance(new Object[] {
                "a", "b", "c", "4" });
        if (testReflect instanceof TestReflect) {
            System.out.println("YES: 我是TestReflect实例变量");
        } else {
            System.out.println("YES: 我不是TestReflect实例变量");
        }
        System.out.println("密码为:" + testReflect.getPassWord());

        // 测试方法的调用
        Method method = clazz.getDeclaredMethod("setUserName",
                new Class[] { String.class });
        method.invoke(testReflect, new Object[] { "good" });

        method = clazz.getDeclaredMethod("getUserName", null);
        System.out.println(method.invoke(testReflect, null));
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassWord() {
        return passWord;
    }

    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }

    public ClassLoader getClassLoader() {
        return classLoader;
    }

    public void setClassLoader(ClassLoader classLoader) {
        this.classLoader = classLoader;
    }

    public String getUserNamePublic() {
        return userNamePublic;
    }

    public void setUserNamePublic(String userNamePublic) {
        this.userNamePublic = userNamePublic;
    }

    public String getPassWordPublic() {
        return passWordPublic;
    }

    public void setPassWordPublic(String passWordPublic) {
        this.passWordPublic = passWordPublic;
    }

    public TestReflect(String userName, String passWord, String userNamePublic,
            String passWordPublic) {
        super();
        this.userName = userName;
        this.passWord = passWord;
        this.userNamePublic = userNamePublic;
        this.passWordPublic = passWordPublic;
    }

    public TestReflect() {
        super();
    }

}