java/android 反射demo，通俗易懂，你值得拥有！！！

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package com.example;

public class Student {

// 变量和setAge、getAge方法都是私有的private String id, name, sex;private int age;private final static String CLASSNAME = "Student";private void setAge(int age) {    this.age = age;}private void getAge() {    System.out.println("age---" + age);}// test方法是公有public void test(int i, int j) {    System.out.println("result---" + (i + j));}

}

package com.example;

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

public class Test {

/** * @param args */public static void main(String[] args) {    // TODO Auto-generated method stub    try {        Class class1 = Class.forName("com.example.Student");        // 或者Class class1 = Student.class;        // 获取所有的变量，包括私有        Field[] fields = class1.getDeclaredFields();        for (int i = 0; i < fields.length; i++) {            // System.out.println(fields[i].getType());            System.out.println(Modifier.toString(fields[i].getModifiers())                    + " " + fields[i].getType().getSimpleName() + " "                    + fields[i].getName());        }        // 获取所有的方法，包括私有        Method[] methods = class1.getDeclaredMethods();        StringBuilder parameterTypeBuilder;        for (int i = 0; i < methods.length; i++) {            parameterTypeBuilder = new StringBuilder(" ");// 为了美观，参数开始、结束加个空格            Class[] classes = methods[i].getParameterTypes();            for (int j = 0; j < classes.length; j++) {// 方法参数类型                if (classes.length > 1) {                    parameterTypeBuilder.append(classes[j].getSimpleName()                            + " ");                } else {                    parameterTypeBuilder.append(classes[j].getSimpleName()                            + " ");                }            }            boolean result = isEmpty(parameterTypeBuilder.toString());            System.out.println(Modifier.toString(methods[i].getModifiers())                    + " "                    + methods[i].getReturnType().getSimpleName()                    + " "                    + methods[i].getName()                    + ((result) ? "()" : "("                            + parameterTypeBuilder.toString() + ")"));            parameterTypeBuilder = null;        }        // 调用私有属性        Student student = (Student) class1.newInstance();// 强转对象        Field ageField = class1.getDeclaredField("age");        ageField.setAccessible(true);        ageField.set(student, 24);// 设置 age值        // 调用私有方法        Method getAgeMethod = class1.getDeclaredMethod("getAge");        getAgeMethod.setAccessible(true);        getAgeMethod.invoke(student);// 调用getAge        //调用私有方法setAge修改值，再打印        Method setAgeMethod = class1.getDeclaredMethod("setAge",int.class);// 调用setAge,该方法有参数        setAgeMethod.setAccessible(true);        setAgeMethod.invoke(student,28);// 设置age        getAgeMethod.invoke(student);// 调用getAge    } catch (Exception e) {        // TODO Auto-generated catch block        e.printStackTrace();    }}private static boolean isEmpty(String text) {    if ("".equals(text) || null == text) {        return true;    }    return false;}

}

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