Controller的使用

缺乏、安全感 2022-06-05 09:20 179阅读 0赞

*  Controller
 *  RestController
    
     *  访问不同路径进到同一个方法
     *  整个类配置路径
     *  GET POST
        
         *  写法
         *  postman工具
     *  请求参数
        
         *  获取url中的参数
         *  获取url中的参数并设置默认值

![这里写图片描述][SouthEast]

# @Controller #

需要配合模板使用！

//pom.xml文件中：
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    </dependencies>

建立模板文件：  
![这里写图片描述][SouthEast 1]

//controller中：
    @Controller  //使用该标签
    public class HelloController { 
    
        @Autowired
        private GirlProperties girlProperties;
    
        @RequestMapping(value="/hello",method = RequestMethod.GET)
        public String say(){
            return  "index"; //返回页面；
        }
    
    }

# @RestController #

@RestController

等同于

@Controller
    @ResponseBody

## 访问不同路径，进到同一个方法 ##

//RequestMapping中配置路径集合；
    @RestController
    public class HelloController { 
    
        @Autowired
        private GirlProperties girlProperties;
    
        @RequestMapping(value={
       "/hello","hi"},method = RequestMethod.GET)
        public String say(){
            return  girlProperties.getCupSize();
        }
    
    }

## 整个类配置路径 ##

@RestController
    @RequestMapping("/hello") //配置整个类路径
    public class HelloController { 
    
        @Autowired
        private GirlProperties girlProperties;
    
        @RequestMapping(value={
       "say"},method = RequestMethod.GET)
        public String say(){
            return  girlProperties.getCupSize();
        }
    
    }

## GET POST ##

### 写法 ###

//@RequestMapping(value="say",method = RequestMethod.GET) //常用写法
        @GetMapping(value="say") //简化写法
        public String say(@RequestParam(value = "id", required = false, defaultValue = "0") Integer myid){
            return  "id = " + myid;
        }

### postman工具 ###

## 请求参数 ##

### 获取url中的参数 ###

//http://localhost:8080/girl/hello/say/100
    
     @RequestMapping(value="say/{id}",method = RequestMethod.GET)
        public String say(@PathVariable("id") Integer myid){
            return  "id = " + myid;
        }

//http://localhost:8080/girl/hello/100/say
    
     @RequestMapping(value="{id}/say",method = RequestMethod.GET)
        public String say(@PathVariable("id") Integer myid){
            return  "id = " + myid;
        }

http://localhost:8080/girl/hello/say?id=100
    
      @RequestMapping(value="say",method = RequestMethod.GET)
        public String say(@RequestParam("id") Integer myid){
            return  "id = " + myid;
        }
    注意：
    http://localhost:8080/girl/hello/say?id=
    此时id=null
    http://localhost:8080/girl/hello/say
    此时页面报错

### 获取url中的参数，并设置默认值 ###

//url中没有参数时，显示默认参数，不报错；
    @RequestMapping(value="say",method = RequestMethod.GET)
        public String say(@RequestParam(value = "id", required = false, defaultValue = "0") Integer myid){
            return  "id = " + myid;
        }

[SouthEast]: /images/20220605/61330149b70d4b189ca271e3772c0d76.png
[SouthEast 1]: /images/20220605/be2f555990024b6a84fc2277d243b5b3.png