doget，dopst，service方法的区别

先看servlet：

package com.szxy.test;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class User extends HttpServlet {
	/*@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		System.out.println("我是service方法");
	}*/
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		System.out.println("我是doGet方法");
	}
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		System.out.println("我是doPost方法");
	}

}

此时我们将jsp中method方法改位post：

由此可见：method决定去调什么方法。当我们将service不注释的时候：

 

这里我们会发现，有service存在时，无论你是post还是get，都会去service方法。当servlet中没有声明对应的请求处理方法，则会报405错误。