springmvc(基础五) Spring3 mvc 获取请求参数的几种方式

springmvc(基础五) Spring3 mvc 获取请求参数的几种方式
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一、通过@PathVariabl获取路径中的参数

@RequestMapping(value="user/{id}/{name}",method=RequestMethod.GET)
    public String printMessage1(@PathVariable String id,@PathVariable String name, ModelMap model) {
        
        System.out.println(id);
        System.out.println(name);
        model.addAttribute("message", "111111");
        return "users";
    }

例如,访问user/123/lei路径时,执行以上方法,其中,参数id=123,name=lei


二、@ModelAttribute获取POST请求的FORM表单数据

jsp代码:

<form method="post" action="hao.do">
    a: <input id="a" type="text"   name="a"/>
    b: <input id="b" type="text"   name="b"/>
    <input type="submit" value="Submit" />
 </form>

实体类:

public class Pojo{
     private String a;
     private int b;
}

Contoller代码:

@RequestMapping(method = RequestMethod.POST) 
public String processSubmit(@ModelAttribute("pojo") Pojo pojo) { 
    
    return "helloWorld"; 
}

三、直接用HttpServletRequest获取

@RequestMapping(method = RequestMethod.GET) 
public String get(HttpServletRequest request, HttpServletResponse response) { 
   System.out.println(request.getParameter("a")); 
   return "helloWorld"; 
}

四、用注解@RequestParam绑定请求参数

用注解@RequestParam绑定请求参数a到变量a

当请求参数a不存在时会有异常发生,可以通过设置属性required=false解决,

例如: 

@RequestParam(value="a", required=false)


Contoller代码:

@RequestMapping(value = "/requestParam", method = RequestMethod.GET) 
public String setupForm(@RequestParam("a") String a, ModelMap model) { 
   System.out.println(a); 
   return "helloWorld";
}


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