springMVC接收数据和响应返回

1. 表单数据

后台直接用形参来接收表单的name。一一对应

@Controller
public class TestController {
    @RequestMapping(value="addUser.do",method= RequestMethod.POST)
    public String postTest2(String age,String userName){
        System.out.print("\n\n userName = "+userName);
        System.out.print("\n\n age = "+age);
        return "redirect:/html/TEST2.html";
    }

}

或者带有注解(这样能够当作转义变量!)：

@RequestMapping(value="addUser.do",method= RequestMethod.POST)
    public String postTest2(@RequestParam("userName") String userName22, @RequestParam("age") Integer age33){
        System.out.print("\n\n userName22 = "+userName22);
        System.out.print("\n\n age33 = "+age33);
        return "redirect:/html/TEST2.html";
    }

又或者使用HttpServletRequest类对象来接收!

可是要添加对应maven依赖

<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>javax.servlet-api</artifactId>
  <version>4.0.1</version>
  <scope>provided</scope>
</dependency>

@RequestMapping(value="addUser.do",method= RequestMethod.POST)
    public String postTest2(@RequestParam("userName") String userName22, @RequestParam("age") Integer age33,HttpServletRequest request){
        System.out.print("\n\n userName22 = "+userName22);
        System.out.print("\n\n age33 = "+age33);
        String username=request.getParameter("userName");
        String password=request.getParameter("age");
        System.out.println("\n\nusername is:"+username);
        System.out.println("\n\npassword is:"+password);
        return "redirect:/html/TEST2.html";
    }

@RequestMapping(value="addUser.do",method= RequestMethod.POST)
    public String postTest2(HttpServletRequest request){
        String username=request.getParameter("userName");
        String password=request.getParameter("age");
        System.out.println("\n\nusername is:"+username);
        System.out.println("\n\npassword is:"+password);
        return "redirect:/html/TEST2.html";
    }

或者这样：接收到时用&拼接的字符串...：str is:userName=11&age=222

@RequestMapping(value="addUser.do",method= RequestMethod.POST)
    public String postTest2(@RequestBody String str){
        System.out.println("\n\nstr is:"+str);
        return "redirect:/html/TEST2.html";
    }

或者一个对象bean类来接收（但不能用@RequestBody来注释）：

@RequestMapping(value="addUser.do",method= RequestMethod.POST)
    public String postTest2(Stu stu){
        System.out.println("\n\nstu is:"+stu);
        System.out.println("\n\nstu is:"+stu.getUserName());
        System.out.println("\n\nstu is:"+stu.getAge());
        return "redirect:/html/TEST2.html";
    }

2. 文件上传(multipart)

A. 首先添加maven依赖包

<dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.3.2</version>
    </dependency>
      <dependency>
          <groupId>commons-net</groupId>
          <artifactId>commons-net</artifactId>
          <version>1.4.1</version>
      </dependency>

B.而后在bean的配置文件(applicationContext.xml或者dispatcher-servlet.xml...配置文件均可以)中，添加<bean>配置以下：

<!--上传文件-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>

C. 前端:必须给form声明为：enctype="multipart/form-data"  而后带有一个file类型的input!注意属性name和变量对应关系!

<form enctype="multipart/form-data" action="addUser.do" method="post">
    <input type="file" name="file">
    <input type="submit" value="上传" />
</form>

D.后台使用MultipartFile类来接收!并来解析

也可使用@RequestPart注解，并使用byte[]来接收二进制，或者用Part类对象接收。三种形式来接收均可以!

@RequestMapping(value="addUser.do",method= RequestMethod.POST)
    public String postTest2(@RequestParam("file") MultipartFile file){
        System.out.println("\n\nage file = :"+file.getOriginalFilename());
        return "redirect:/html/TEST2.html";
    }

PS.固然能够支持多个文件同时上传并设置上传最大容量的阈值l

E.限定上传文件大小

<!--上传文件-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="1000000"></property>
    </bean>

3. 发送头部数据