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   在学习controller的时候，测试了在RequestMapping中，value参数中配置集合，实现不同的URL访问同一方法。

   本章继续学习和测试RequestMapping的其他特性。

  一.PathVariabe获取URL参数，代码如下：

package com.yy.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.ModelAndView;

/**
 * Created by Administrator on 2018-05-18.
 */
@RestController
//@Controller
public class HelloController {
    @RequestMapping(value = "/hello1",method= RequestMethod.GET)
    public  String sayHello1()
    {
        String hello="index";
        return hello;
    }
    @ResponseBody
    @RequestMapping(value = {"/hello2","/index2"},method= RequestMethod.GET)
    public  String sayHello2()
    {
        String hello="index";

        return hello;
    }

    @RequestMapping(value = "/hello3",method= RequestMethod.GET)
    public ModelAndView sayHello3()
    {
        ModelAndView mv = new ModelAndView("index");
        return mv;
    }
//    URL参数
    @RequestMapping(value = "/hello4/{name}",method= RequestMethod.GET)
    public String sayHello4(@PathVariable("name") String name )
    {
        String str=name;
        return str;
    }


}

启动应用，访问URL：http://localhost:8088/sptest/hello4/lilei，则方法sayHello4获取的name参数值为lilei，方法返回name值，则显示如下：

二.使用@RequestMapping给整个类指定URL映射

package com.yy.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.ModelAndView;

/**
 * Created by Administrator on 2018-05-18.
 */
@RestController
//@Controller
@RequestMapping(value="my")
public class HelloController {
    @RequestMapping(value = "/hello1",method= RequestMethod.GET)
    public  String sayHello1()
    {
        String hello="index";
        return hello;
    }
    @ResponseBody
    @RequestMapping(value = {"/hello2","/index2"},method= RequestMethod.GET)
    public  String sayHello2()
    {
        String hello="index";

        return hello;
    }

    @RequestMapping(value = "/hello3",method= RequestMethod.GET)
    public ModelAndView sayHello3()
    {
        ModelAndView mv = new ModelAndView("index");
        return mv;
    }
//    URL参数
    @RequestMapping(value = "/hello4/{name}",method= RequestMethod.GET)
    public String sayHello4(@PathVariable("name") String name )
    {
        String str=name;
        return str;
    }


}

其他不变，给HelloController类添加@RequestMapping注解。启动应用访问URL：

三.按照传统方式Url+"?name=lilei"传递参数

 //传统URL参数
    @RequestMapping(value = "/hello5",method= RequestMethod.GET)
    public String sayHello5(@RequestParam(value="name",required = false,defaultValue = "james") String name )
    {
        String str=name;
        return str;
    }

获取参数使用@RequestParam，其中value值为url中参数的名称；required默认为true，表示参数必须，此处修改为false；defaultValue为该参数默认值，如果url中没有为该参数指定值，则使用该默认值，如果参数已传递，则用获取的参数值覆盖该默认值。

用如下URL访问：http://localhost:8088/sptest/my/hello5/?name=chole，显示如下：

 四.使用GetMapping代替RequestMapping

其他不变，将上面代码中的sayHello5注解改为@GetMapping(value = "/hello5")