Controller中注解的使用:
@Controller
●该注解用来响应页面，必须配合模板来使用
@RestController
●该注解可以直接响应字符串，返回的类型为JSON格式
1 package com.example.demo.controller;
2
3 import org.springframework.web.bind.annotation.RequestMapping;
4 import org.springframework.web.bind.annotation.RestController;
5
6 @RestController
7 public class HelloWorldController {
8
9 @RequestMapping("/")
10 public String index() {
11 return "Hello World";
12 }
13 }
启动程序，访问http://localhost:8080/，返回Hello World
@RequestMapping
●指定URL访问中的前缀
1 package com.example.demo;
2
3 import org.springframework.boot.SpringApplication;
4 import org.springframework.boot.autoconfigure.SpringBootApplication;
5
6 @SpringBootApplication
7 public class DemoApplication {
8
9 public static void main(String[] args) {
10 SpringApplication.run(DemoApplication.class, args);
11 }
12 }
访问http://localhost:8080/hello，返回Hello World
@RequestParam
●获取请求URL中参数的变量
1 package com.example.demo.controller;
2
3 import org.springframework.web.bind.annotation.RequestMapping;
4 import org.springframework.web.bind.annotation.RequestMethod;
5 import org.springframework.web.bind.annotation.RequestParam;
6 import org.springframework.web.bind.annotation.RestController;
7
8 @RestController
9 public class HelloWorldController {
10
11 @RequestMapping(value="/hello",method=RequestMethod.GET)
12 public String index(@RequestParam("name")String name) {
13 return "Hello World:"+name;
14 }
15 }
访问http://localhost:8080/hello?name=张三，返回Hello World：张三
@PathVariable
●获取请求URL中路径的变量
1 package com.example.demo.controller;
2
3 import org.springframework.web.bind.annotation.PathVariable;
4 import org.springframework.web.bind.annotation.RequestMapping;
5 import org.springframework.web.bind.annotation.RequestMethod;
6 import org.springframework.web.bind.annotation.RestController;
7
8 @RestController
9 public class HelloWorldController {
10
11 @RequestMapping(value="/hello/{name}",method=RequestMethod.GET)
12 public String index(@PathVariable("name")String name) {
13 return "Hello World:"+name;
14 }
15 }
访问http://localhost:8080/hello/张三，返回Hello World：张三
@GetMapping/@PostMapping
●与RequestMapping类似，不同的是指定了请求的方式(get/post)
1 package com.example.demo.controller;
2
3 import org.springframework.web.bind.annotation.GetMapping;
4 import org.springframework.web.bind.annotation.RestController;
5
6 @RestController
7 public class HelloWorldController {
8
9 @GetMapping(value="/hello")
10 public String index() {
11 return "Hello World";
12 }
13 }
总结
Controller是SpringBoot里比较常用的组件，通过匹配客户端提交的请求，分配不同的处理方法，然后向客户端返回结果。
