Java反射代码块

<span style="font-size:14px;">import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.lang.reflect.Constructor;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.lang.reflect.Modifier;import java.util.Properties;public class Test_Reflection {public static void main(String[] args){//获取对象//1.编译器已经知道名字Class c1 = TestReflection.class;//2.已经的到类的实例对象TestReflection tf = new TestReflection();Class c2 = tf.getClass();//3.通过运行期获取名字//Class c3 = Class.forName("test.TestReflection");//读取属性文件，在运行期获取对象Class c3 = null;Properties p = new Properties();try {FileInputStream fis = new FileInputStream("prop.properties");p.load(fis);String className = p.getProperty("className");System.out.println(className);c3 = Class.forName(className);fis.close();} catch (IOException e) {e.printStackTrace();} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}//==========================================================================================//获取指定包名String package1 = c1.getPackage().getName();String package3 = c3.getPackage().getName(); System.out.println(package1 + "   " + package3);//==========================================================================================//获取类权限修饰符int mod = c3.getModifiers();String modifier = Modifier.toString(mod);System.out.println("类的权限修饰符:" + modifier);//获取完整类名String className = c3.getName();System.out.println("完整类名:" + className);//获取父类Class superClass = c3.getSuperclass();System.out.println(Modifier.toString(superClass.getModifiers()) + " class " + superClass.getName());//获取实现接口Class [] interfaces = c3.getInterfaces();for(Class t : interfaces){System.out.println(Modifier.toString(t.getModifiers()) + " interface " + t.getName());}//==========================================================================================//获取成员变量Field [] fds = c3.getDeclaredFields();for(Field field : fds){//获取每个字段的访问修饰符String mods = Modifier.toString(field.getModifiers());//获取每个字段的类型Class type = field.getType();//得到类型名String typeName = type.getName();//得到字段名String fieldName = field.getName();//如果是数组，需要特殊处理一下if(type.isArray()){typeName = type.getComponentType().getName() + "[]";}System.out.println(mods + " " + typeName + " " + fieldName);}//==========================================================================================//获取构造方法Constructor [] constructors = c3.getDeclaredConstructors();for(Constructor constructor : constructors){//获取构造方法名String consName = constructor.getName();//获取构造方法访问修饰符String consModifier = Modifier.toString(constructor.getModifiers());//获取构造方法中的参数Class [] paramTypes = constructor.getParameterTypes();System.out.print(consModifier + " " + consName + "(");//循环所有参数类型for(int i=0;i<paramTypes.length;i++){//如果第一个参数后需要加上逗号if(i > 0){System.out.print(", ");}//如果是数组需要特殊处理if(paramTypes[i].isArray()){System.out.print(paramTypes[i].getComponentType().getName() + "[]");}else{System.out.print(paramTypes[i].getName());}}System.out.println(")");}//==========================================================================================//获取成员方法Method [] methods = c3.getDeclaredMethods();//遍历所有成员方法for(Method m : methods){//获取访问修饰符String mMod = Modifier.toString(m.getModifiers());//获取返回值类型Class mType = m.getReturnType();String returnType = "";if(mType.isArray()){returnType = mType.getComponentType().getName() + "[]";}else{returnType = mType.getName();}String mName = m.getName();System.out.print(mMod + " " + returnType + " " + mName + "(");//获取参数列表Class [] paramTypes = m.getParameterTypes();for(int i=0;i<paramTypes.length;i++){if(i > 0){System.out.print(", ");}if(paramTypes[i].isArray()){System.out.print(paramTypes[i].getComponentType().getName() + "[]");}else{System.out.print(paramTypes[i].getName());}}System.out.println(")");}//==========================================================================================//反射调用方法，可以通过Method类的invoke方法实现动态方法的调用//public Object invoke(Object obj,Object...args)//第一个参数代表对象//第二个参数开始，代表执行方法上的参数//若反射要调用类的某个私有方法,可以在这个私有方法对应的Method对象上先调用setAccessible(true)//之前已经获取了c3的class对象，首先获得实例化对象，然后对变量直接赋值查看结果try {//通过newInstance()方法获取实例化对象//但是直接通过这种方法无法访问带参数的构造方法TestReflection trf = (TestReflection)c3.newInstance();trf.name = "张三";trf.password = "123456";trf.score = new int[3];trf.score[0] = 90;trf.score[1] = 91;trf.score[2] = 92;System.out.println("name=====" + trf.name);//通过构造方法同样可以实例化对象//要调用带参数的构造方法生成对象，可以使用下面的方式Constructor cons = c3.getConstructor(new Class[]{String.class,String.class});Object obj = cons.newInstance(new Object[]{"zhangsan","abcdefg"});TestReflection trf2 = ((TestReflection)obj);System.out.println("trf2-name=====" + trf2.name);System.out.println("trf2-password=====" + trf2.password);//注意:getDeclaredMethod()获取的是类自身声明的所有方法，//包括public，protected和private方法//getMethod()获取的是类的所有共有方法，//意思是包括自身所有的public方法。以及从父类继承，从接口实现的所有public方法//通过反射调用方法Method method1 = c3.getDeclaredMethod("setName", String.class);method1.invoke(trf, "李四");//通过反射调用带数组参数的方法Method method2 = c3.getDeclaredMethod("setScore", new Class[]{int[].class});int [] nums = {1,2,3};method2.invoke(trf,new Object[]{nums});//通过反射调用private修饰的方法Method method3 = c3.getDeclaredMethod("setPassword", String.class);method3.setAccessible(true);method3.invoke(trf,"aabbccdd");System.out.println("name=====" + trf.name);System.out.println("scores====" + trf.score[0]);System.out.println("password=====" + trf.password);} catch (InstantiationException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (NoSuchMethodException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (SecurityException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalArgumentException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (InvocationTargetException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}</span>