Reflect in Java

我会带着你远行 2021-12-05 18:49 175阅读 0赞

java反射的使用:

1 package com.test.struts2;
      2 
      3 import java.lang.reflect.Constructor;
      4 import java.lang.reflect.Field;
      5 import java.lang.reflect.Method;
      6 
      7 import com.opensymphony.module.sitemesh.util.ClassLoaderUtil;
      8 
      9 public class TestReflect {
        
     10 
     11     private String userName;
     12 
     13     private String passWord;
     14 
     15     public String userNamePublic;
     16 
     17     public String passWordPublic;
     18 
     19     private ClassLoader classLoader;
     20 
     21     public static void main(String[] args) throws Exception {
        
     22 
     23         Class clazz = Class.forName("com.test.struts2.TestReflect");
     24 
     25         // 通过线程获取ClassLoder
     26         Class clazz1 = Thread.currentThread().getContextClassLoader()
     27                 .loadClass("com.test.struts2.TestReflect");
     28 
     29         // 通过.class获取ClassLoder(TestReflect参数只可以使自己包中命名的类)
     30         Class clazz2 = TestReflect.class.getClassLoader().loadClass(
     31                 "com.test.struts2.TestReflect");
     32 
     33         // Struts2中的ClassLoaderUtil类，对线程获取进行了分装
     34         Class clazz3 = ClassLoaderUtil.loadClass(
     35                 "com.test.struts2.TestReflect", String.class);
     36 
     37         // 新建实例(newInstance建立)
     38         TestReflect testReflect = (TestReflect) clazz.newInstance();
     39 
     40         // 属性(所有的的属性)
     41         Field[] fields = clazz.getDeclaredFields();
     42         System.out.println("---------所有属性 ");
     43         for (Field field : fields) {
        
     44             System.out.println(field.getName());
     45         }
     46 
     47         // 属性(public的属性)
     48         System.out.println("---------public属性 ");
     49         Field[] fieldsPublic = clazz.getFields();
     50         for (Field field : fieldsPublic) {
        
     51             System.out.println("public属性: " + field.getName());
     52         }
     53 
     54         // 通过getXXX和setXXX方法访问八个基本类型的值
     55 // 如果该属性类型是引用类型则直接使用get(Object obj)
     56         Field f = clazz.getDeclaredField("userName");
     57         testReflect.setUserName("Hello");
     58         System.out.println(f);
     59         f.setAccessible(true);
     60         f.set(testReflect, "111");
     61         System.out.println(testReflect.getUserName());
     62         System.out.println("调用了该方法：" + f.get(testReflect));
     63 
     64         System.out.println("---------所有方法 ");
     65         // 所有的方法
     66         Method[] methods = clazz.getDeclaredMethods();
     67         for (Method method : methods) {
        
     68             System.out.println(method.getName());
     69         }
     70 
     71         System.out.println("---------public方法 ");
     72         // public的方法
     73         Method[] methodsPublic = clazz.getDeclaredMethods();
     74 
     75         for (Method method : methodsPublic) {
        
     76             System.out.println("public方法: " + method.getName());
     77         }
     78 
     79         // 方法的调用
     80         for (Method method : methodsPublic) {
        
     81             System.out.println("调用了方法: " + method.getName());
     82             // method.invoke(obj, args);
     83         }
     84 
     85         System.out.println("---------构造器 ");
     86         // 构造器
     87         Constructor[] Constructors = clazz.getConstructors();
     88         for (Constructor constructor : Constructors) {
        
     89             System.out.println("构造器: " + constructor.getName());
     90         }
     91 
     92         if (testReflect instanceof TestReflect) {
        
     93             System.out.println("YES: 我是TestReflect实例变量");
     94         } else {
        
     95             System.out.println("YES: 我不是TestReflect实例变量");
     96         }
     97 
     98         // 通过构造器实例化(),默认构造器
     99         Constructor constructor = clazz.getConstructor(new Class[] {});
    100         testReflect = (TestReflect) constructor.newInstance();
    101         if (testReflect instanceof TestReflect) {
        
    102             System.out.println("YES: 我是TestReflect实例变量");
    103         } else {
        
    104             System.out.println("YES: 我不是TestReflect实例变量");
    105         }
    106 
    107         // 通过构造器实例化(),默认构造器
    108         Constructor constructorss = clazz.getConstructor(new Class[] {
        
    109                 String.class, String.class, String.class, String.class });
    110         testReflect = (TestReflect) constructorss.newInstance(new Object[] {
        
    111                 "a", "b", "c", "4" });
    112         if (testReflect instanceof TestReflect) {
        
    113             System.out.println("YES: 我是TestReflect实例变量");
    114         } else {
        
    115             System.out.println("YES: 我不是TestReflect实例变量");
    116         }
    117         System.out.println("密码为:" + testReflect.getPassWord());
    118 
    119         // 测试方法的调用
    120         Method method = clazz.getDeclaredMethod("setUserName",
    121                 new Class[] { String.class });
    122         method.invoke(testReflect, new Object[] { "good" });
    123 
    124         method = clazz.getDeclaredMethod("getUserName", null);
    125         System.out.println(method.invoke(testReflect, null));
    126     }
    127 
    128     public String getUserName() {
        
    129         return userName;
    130     }
    131 
    132     public void setUserName(String userName) {
        
    133         this.userName = userName;
    134     }
    135 
    136     public String getPassWord() {
        
    137         return passWord;
    138     }
    139 
    140     public void setPassWord(String passWord) {
        
    141         this.passWord = passWord;
    142     }
    143 
    144     public ClassLoader getClassLoader() {
        
    145         return classLoader;
    146     }
    147 
    148     public void setClassLoader(ClassLoader classLoader) {
        
    149         this.classLoader = classLoader;
    150     }
    151 
    152     public String getUserNamePublic() {
        
    153         return userNamePublic;
    154     }
    155 
    156     public void setUserNamePublic(String userNamePublic) {
        
    157         this.userNamePublic = userNamePublic;
    158     }
    159 
    160     public String getPassWordPublic() {
        
    161         return passWordPublic;
    162     }
    163 
    164     public void setPassWordPublic(String passWordPublic) {
        
    165         this.passWordPublic = passWordPublic;
    166     }
    167 
    168     public TestReflect(String userName, String passWord, String userNamePublic,
    169             String passWordPublic) {
        
    170         super();
    171         this.userName = userName;
    172         this.passWord = passWord;
    173         this.userNamePublic = userNamePublic;
    174         this.passWordPublic = passWordPublic;
    175     }
    176 
    177     public TestReflect() {
        
    178         super();
    179     }
    180 
    181 }

转载于:https://www.cnblogs.com/caroline/archive/2012/03/06/2382555.html