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

 

package com.example.demo.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloWorldController {

   @RequestMapping("/")    
   public String index() {
        return "Hello World";
    }
}

 启动程序，访问http://localhost:8080/，返回Hello World

  @RequestMapping

  ●指定URL访问中的前缀

  

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

 

访问http://localhost:8080/hello，返回Hello World

  @RequestParam

  ●获取请求URL中参数的变量

  

package com.example.demo.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloWorldController {

   @RequestMapping(value="/hello",method=RequestMethod.GET)    
   public String index(@RequestParam("name")String name) {
        return "Hello World:"+name;
    }
}

 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

 

package com.example.demo.controller;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloWorldController {

   @RequestMapping(value="/hello/{name}",method=RequestMethod.GET)    
   public String index(@PathVariable("name")String name) {
        return "Hello World:"+name;
    }
}

 

 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)

 

package com.example.demo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloWorldController {

   @GetMapping(value="/hello")    
   public String index() {
        return "Hello World";
    }
}

 

 

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。