SpringBoot入门(二):Controller的使用

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。