SpringMVC learning ____4 front-end controller parameters were inconsistent and passed the resolution objects

code show as below:

1.SpringMVC web.xml file: (DispatcherServlet configuration)

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
         http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         id="WebApp_ID" version="3.0">

  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc-servlet.xml</param-value>
    </init-param>

    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>


</web-app>

2.SpringMVC configuration file (springmvc-servlet.xml)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd " > 


    <-! automatically scan packages -> 
    < context: Scan-Component Base-Package =" com.xbf.controller " / > 

    <! - static resource filter processing SpringMVC not static resources -> 
    < MVC: the servlet-default-Handler /> 

    <! - annotation driving -> 
    < MVC: annotation-driven /> 

    <-! view resolver -> 
    < the bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver" > 
        < Property name = "prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

3.Controller layer write:

Package com.xbf.controller; 


Import com.xbf.pojo.User;
 Import org.springframework.stereotype.Controller;
 Import org.springframework.ui.Model;
 Import org.springframework.web.bind.annotation.PathVariable;
 Import ORG. springframework.web.bind.annotation.RequestMapping;
 Import org.springframework.web.bind.annotation.RequestParam; 

@Controller 
public  class the UserController { 

    @RequestMapping ( "/ T1 / {name}" )
     // RESTful style
     // distal request parameters and parameter names when processing the same
     // can take over directly with the
     // parameter name String name is the front-end request
    public String test1 (@PathVariable String name, the Model Model) { 
        model.addAttribute ( "AAA" , name);
         return "User" ; 
    } 

    @RequestMapping ( "/ T2" )
     // distal parameter name and pass over the process controller the parameter name is inconsistent
     // used for explanation @RequestPara annotation
     @ username: front end of the passed parameter names
     @ name: the name of the controller processing parameters 
    public String test2 (@RequestParam (value = "username" ) String name , the Model Model) { 
        model.addAttribute ( "AAA" , name);
         return "User" ;
    }


    @RequestMapping("/ T3" )
     // pass the research object
     // using the set method to set the value of the property, if no value is passed to the default value, set value before determining whether it is consistent attribute name? ? ?
    // will transfer from the front end of the value of the object property to the object automatic packaging (User) 
    public String Test3 (the User User, the Model Model) { 
        System.out.println (User); 
        model.addAttribute ( "User" , User) ;
         return "User" ; 
    } 

    @RequestMapping ( "/ T333 / {ID} / {name} / {} Age" )
     // RESTful style 
    public String test33 (the User User, the Model Model) { 
        System.out.println (User) ; 
        model.addAttribute ( "the User" , the User);
        ;
    }

    @RequestMapping("/t33/{id}/{name}/{age}")
    //restful风格
    public String test33(@PathVariable int id,@PathVariable String name,@PathVariable int age,Model model){
        User user = new User();
        user.setName(name);
        user.setId(id);
        user.setAge(age);
        System.out.println(user);
        model.addAttribute("user",user);
        return "user";
    }


}

4. The front page (user.jsp)

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

${aaa}


<hr>

<p>
    姓名：${user.getName()}
    ID：${user.getId()}
    年龄：${user.getAge()}
</p>

</body>
</html>

pojo entity classes:

package com.xbf.pojo;

public class User {

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

    public User() {
    }

    public User(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public int getId() {
        return id;
    }

    public void setId(int 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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

Summary: DispatcherServlet will intercept the requests distributed to the front end of a specific controller, the model data is processed by the controller and returned.