88 lines
3.2 KiB
Java
88 lines
3.2 KiB
Java
package test;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.Field;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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public class Test {
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public static String classname="类.Student";
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public static String fieldname="name";
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public static String methodname="setName";
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public static String[] mptypes= {"java.lang.String"};
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public static Object fvalue=new String("xiaolin");
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public static Object mp1=new String("xiaohong");
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public static void main(String[] args) {
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// TODO Auto-generated method stub
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try {
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Class c=Class.forName(classname);//根据类名字符串获得类对应的Class实例
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//第一种用反射创建类对象的方法，相当于调用类的无参数构造方法
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Object o=c.newInstance();//Student o=new Student();
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//使用反射访问类对象的属性（给属性设置值，获取属性的值）
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Field f=c.getDeclaredField(fieldname);//根据Field名，获得Field对象
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f.setAccessible(true);
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f.set(o,fvalue);//o.name="xiaolin";使用反射给o对象的f代表的属性设置值为发value的值
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System.out.println(f.get(o));//获取o对象的f属性对应的值，并输出
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@SuppressWarnings("unchecked")
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//使用反射调用对象的方法
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//使用反射根据方法名，和参数类型、参数数量来获取具体某个方法
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Method m=c.getDeclaredMethod(methodname, Class.forName(mptypes[0]));//String.class
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//方法的调用，调用o对象的m方法，方法的实际参数是mp1，mo是方法调用的返回值
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Object mo=m.invoke(o,mp1);//o.setName("xiaohong");
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System.out.println(mo);
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//调用了o对象名为setAge，参数有1个，类型是int型的方法，实际参数是21
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m=c.getDeclaredMethod("setAge", int.class);
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m.invoke(o, 21);
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System.out.println(o);
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/*Method m=c.getDeclaredMethod(methodname);
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Object mo=m.invoke(o);
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System.out.println(mo);
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System.out.println(f.get(o));*/
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@SuppressWarnings({ "unchecked", "rawtypes" })
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//第二种用反射创建类对象的方法，先获取具体的Constructor，再用Constructor去创建对象
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Constructor con=c.getDeclaredConstructor(String.class,int.class);//根据构造方法参数类型来获取某个构造方法
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Object o1=con.newInstance("Mary",20);
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//用Constructor创建类对象，相当于Student o1=new Student("Mary",20);
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System.out.println(o1);
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} catch (ClassNotFoundException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (NoSuchFieldException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (SecurityException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (InstantiationException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (IllegalAccessException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (NoSuchMethodException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (IllegalArgumentException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (InvocationTargetException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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}
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}
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