Spring MVC参数接收 总结

1. 简介

Spring MVC可以简化从前端接收参数的步骤。

2. Param传参

通过设定函数入参和添加标记来简化接受：

//参数接收
@RequestMapping("product")
@ResponseBody
//接受/product?product=goods&id=123
//1.名称必须相同，2.不传值不会不报错
public String product(String product, int id){
    System.out.println("product = " + product+ ", id = " + id);
    return "product = " + product+ ", id = " + id;
}

//注解指定
//pdt必须传递并转化成product，不传就报400异常
//id可以不传递，不传默认值就是1
@RequestMapping("product1")
@ResponseBody
public String product1(@RequestParam(value = "pdt") String product, @RequestParam(required = false,defaultValue = "1") int id){
    System.out.println("product = " + product+ ", id = " + id);
    return "product = " + product+ ", id = " + id;
}

//特殊值 ids=1&ids=2&ids=3
@GetMapping("product2")
@ResponseBody
public String product2(@RequestParam  List<String> ids){//@RequestParam必须加
    System.out.println("hbs = " + ids);
    return "ok";

}

//数据直接放到数据类里，要求名字必须相同
//如果没传就用默认值，都不会报错
@RequestMapping("product3")
@ResponseBody
public String product3(Product product){
    System.out.println("product" + product);
    return product.toString();
}

3. 动态路径传参

也可以直接从动态路径接受参数：

//动态路径用{}括起来
//接收路径参数用PathVariable标记
@RequestMapping("{pdt}/{id}")
public String login(@PathVariable("pdt") String product, @PathVariable String id){
    System.out.println("product = " + product + ", id = " + id);
    return "product = " + product + ", id = " + id;
}

4. JSON传参

从前端传来的JSON解析接收方法如下：
pom.xml中导入json依赖：

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.15.0</version>
</dependency>

配置类中加入@EnableWebMvc注解：

...
@EnableWebMvc
public class MVCConfig {
...
}

业务逻辑实现：

@RequestMapping("/")
@Controller
@ResponseBody
public class JsonController {
    @RequestMapping(value = "product",method = RequestMethod.POST)
    public String data(@RequestBody Product product){//@RequestBody表示接受json数据
        System.out.println("product = " + product);
        return product.toString();
    }
}

5.接收Cookie

通过@CookieValue标注接受Cookie

@RequestMapping
public String data(@CookieValue(value = "cookieName") String cookie){
    System.out.println("cookie = " + cookie);
    return "ok";
}

6.接收Header

通过@RequestHeader标注接受Header:

@RequestMapping
public String data(@RequestHeader("Connection") String conn){//接收header的Connection字段
    System.out.println("conn = " + conn);
    return "conn = " + conn;
}

7.获取原生对象

原生对象可以直接在函数入参获取：

@Controller
public class dataController {
    @Autowired
    private ServletContext servletContext;//通过IOC自动获取ServletContext对象

    public void api(HttpServletResponse response, HttpServletRequest request, HttpSession session) {//获取HttpServletResponse，HttpServletRequest，HttpSession对象
        //获取ServletContext对象
        ServletContext servletContext1 = request.getServletContext();
        ServletContext servletContext2 = session.getServletContext();
    }
}

原文地址：https://blog.csdn.net/a827143452/article/details/142458657

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