@RequestParam注解的用法

JiuyeXD

December 27, 2020

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2313 words

技术杂谈

**1、作用：**

```
@RequestParam：将请求参数绑定到你控制器的方法参数上（是springmvc中接收普通参数的注解）
```

**2、语法：**

```
语法：@RequestParam(value=”参数名”,required=”true/false”,defaultValue=””) value：参数名 required：是否包含该参数，默认为true，表示该请求路径中必须包含该参数，如果不包含就报错。 defaultValue：默认参数值，如果设置了该值，required=true将失效，自动为false,如果没有传该参数，就使用默认值
```

**3、业务处理器HelloController.java**

```java
package ro.qwq.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

@Controller //标注这个Class是一个控制器
@RequestMapping("hello")
public class HelloController {

/**
     * 接收普通请求参数
     * http://localhost:8080/hello/show16?name=linuxsir
     * url参数中的name必须要和@RequestParam("name")一致
     * @return
     */
    @RequestMapping("show16")
    public ModelAndView test16(@RequestParam("name")String name){
        ModelAndView mv = new ModelAndView();
        mv.setViewName("hello2");
        mv.addObject("msg", "接收普通的请求参数：" + name);
        return mv;
    }

/**
     * 接收普通请求参数
     * http://localhost:8080/hello/show17
     * url中没有name参数不会报错、有就显示出来
     * @return
     */
    @RequestMapping("show17")
    public ModelAndView test17(@RequestParam(value="name",required=false)String name){
        ModelAndView mv = new ModelAndView();
        mv.setViewName("hello2");
        mv.addObject("msg", "接收普通请求参数：" + name);
        return mv;
    }

/**
     * 接收普通请求参数
     * http://localhost:8080/hello/show18?name=998 显示为998
     * http://localhost:8080/hello/show18?name 显示为hello
     * @return
     */
    @RequestMapping("show18")
    public ModelAndView test18(@RequestParam(value="name",required=true,defaultValue="hello")String name){
        ModelAndView mv = new ModelAndView();
        mv.setViewName("hello2");
        mv.addObject("msg", "接收普通请求参数：" + name);
        return mv;
    }
}
```

**4、测试**

![](https://old.qwq.ro/usr/uploads/2020/12/255789646.jpg)

![](https://old.qwq.ro/usr/uploads/2020/12/87315903.jpg)

![](https://old.qwq.ro/usr/uploads/2020/12/3890044782.jpg)

![](https://old.qwq.ro/usr/uploads/2020/12/3225329990.jpg)

转自: https://blog.csdn.net/sswqzx/article/details/84195043

Last modification：December 27, 2020