几个简单的反例示例

准备条件：
1. 创建工程Reflection
示例1：
DumpMethods.java

package com.test;

import java.lang.reflect.Method;

public class DumpMethods {

	//从命令行接受一个字符串(该字符串是某个类的全名)
	//打印出该类中的所有方法声明
	public static void main(String[] args) throws ClassNotFoundException {
		
		//Class类是Java反射的入口点
		Class<?> classType=Class.forName(args[0]);
		
		Method[] methods=classType.getDeclaredMethods();
		
		for(Method method : methods){
			System.out.println(method);
		}
		
	}

}

示例2
InvokeTester.java

package com.test;

import java.lang.reflect.Method;

public class InvokeTester {

	public int add(int param1,int param2){
		return param1+param2;
	}
	
	public String echo(String msg){
		return "hello:"+msg;
	}
	
	public static void main(String[] args) throws Exception {
		
		//会获得InvokeTester类所对应的Class对象
		Class<?> classType=InvokeTester.class;

		Object invokeTester=classType.newInstance();
		
		//以上两行代码等价于
		//InvokeTester i=new InvokeTester();
		
		Method addMethod=classType.getMethod("add", new Class[]{int.class,int.class});
		
		Object result=addMethod.invoke(invokeTester, new Object[]{1,2});
		
		//以上两行代码等价于
		//i.add(1,2);
		
		System.out.println((Integer)result);
		
		Method echoMethod=classType.getMethod("echo", new Class[]{String.class});
		
		Object result2=echoMethod.invoke(invokeTester, new Object[]{"world"});
		
		//以上两行代码等价于
		//i.echo("world");
		
		System.out.println((String)result2);
		
	}

}

示例3
ReflectTester.java

package com.test;

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

public class ReflectTester {

	public Object copy(Object obj) throws Exception {

		Class<?> classType = obj.getClass();

		System.out.println(classType.getName());

		Object objectCopy = classType.getConstructor(new Class[] {})
				.newInstance(new Object[] {});

		Field[] fields = classType.getDeclaredFields();

		for (Field field : fields) {
			String fieldName = field.getName();

			//获得属性首字母并转换为大写
			String firstLetter = fieldName.substring(0, 1).toUpperCase();

			//获得和属性对应的getXXX()方法的名字
			String getMethodName = "get" + firstLetter + fieldName.substring(1);
			//获得和属性对应的setXXX()方法的名字
			String setMethodName = "set" + firstLetter + fieldName.substring(1);

			Method getMethod = classType.getMethod(getMethodName, new Class[] {});

			Object value = getMethod.invoke(obj, new Object[] {});

			Method setMethod = classType.getMethod(setMethodName, new Class[] { field
					.getType() });

			setMethod.invoke(objectCopy, new Object[] { value });
		}

		return objectCopy;
	}

	public static void main(String[] args) throws Exception {
		Customer cust = new Customer();
		cust.setId(new Long(1));
		cust.setName("张三");
		cust.setAge(22);

		Customer copycust = (Customer) new ReflectTester().copy(cust);

		System.out.println(copycust.getId() + ":" + copycust.getName() + ":"
				+ copycust.getAge());
	}

}

class Customer {
	
	public Customer(){}

	private Long id;
	private String name;
	private int age;

	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

}