Question

我是春天的新人。我已经开始制作一个Web应用程序来上传文件然后写入数据库。我在Netbeans中使用Spring MVC和Maven制作它。

我根据本教程制作了一个完全正常的基础项目

https://saarapakarinen.wordpress.com/2015/01/11/building-a-basic-spring-3-web-project-netbeans-and-maven/

并尝试为我的应用程序扩展它，想要根据官方Spring教程制作文件上传组件

http://docs.spring.io/spring/docs/3.0.x/spring-framework-reference/html/mvc.html#mvc-multipart

但它不起作用，出现错误：

HTTP状态400 - 必需的MultipartFile参数'file'不存在

我使用wyslij.jsp（上传文件的格式）扩展了这个项目

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Wysylanie pliku</title>
    </head>

<body>
    <form method="get" action="http://localhost:8084/Hello/application/wyslij" enctype="multipart/form-data">
            <input type="file" name="file"/>
            <input type="submit"/>
        </form>
</body>


</html>

并为上传文件添加了一个名为UpladController.java的文件

package helloweb;

import java.io.IOException;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class UploadController 
{

    @RequestMapping(value = "wyslij", method = RequestMethod.GET)
    public String handleFormUpload(@RequestParam("file") MultipartFile file) throws IOException 
    {

        if (!file.isEmpty()) {
            byte[] bytes = file.getBytes();
            // store the bytes somewhere
           return "redirect:tak";
       } else 
        {
           return "redirect:nie";
       }
    }

}

web.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee                               http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <!-- name of the project//-->
    <display-name>HelloProject</display-name>
    <servlet>
        <servlet-name>front-controller</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>front-controller</servlet-name>
        <url-pattern>/application/*</url-pattern>
    </servlet-mapping>

    <!-- max time of the session //-->

    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <!-- default page //-->
    <welcome-file-list>
        <welcome-file>application/wyslij.jsp</welcome-file>
    </welcome-file-list>
</web-app>

和front-controller-serlvet.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-3.0.xsd">

     <!-- configuration to fetch jsp files automatically from WEB-INF/jsp -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> 
        <property name="prefix" value="/WEB-INF/jsp/" /> 
        <property name="suffix" value=".jsp" /> 
    </bean>

    <bean id="multipartResolver"
    class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

    <!-- one of the properties available; the maximum file size in bytes -->
    <property name="maxUploadSize" value="100000"/>

</bean>



    <context:component-scan base-package="helloweb" />

</beans>

有人能说出来，为什么会出现错误并解释？

编辑：

我决定使用教程中制作的form.jsp和HelloController.java并将其转换为文件上传（它们比我的代码工作更多）

form.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

        <title>Form Page</title>
    </head>
    <body>

            <form method="POST" enctype="multipart/form-data" action="http://localhost:8084/Hello/application/form">
              <label>file to send: <input type="file" name="file" /></label>
              <input type="submit" />
            </form>
    </body>
</html>

和HelloController.java

package helloweb;

import java.io.IOException;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;


@Controller
public class HelloController 
{ 
    @RequestMapping(value = "form", method = RequestMethod.POST)
    public String login(@RequestParam(value = "file", required = true) MultipartFile file) throws IOException 
    {
                    if (!file.isEmpty()) 
                    {
            byte[] bytes = file.getBytes();
            // store the bytes somewhere
           return "redirect:tak";
       } 
                    else 
        {
           return "redirect:nie";
        }

    }

        @RequestMapping("form")
    public String viewLoginPage(Model model)
    {  
        return "form";
    }
}

现在我至少在开始页面上正确显示了文件上传表单，但是在选择文件并单击按钮后，我得到了更多错误：

HTTP Status 500 - Could not parse multipart servlet request; nested exception is java.lang.IllegalStateException: Unable to process parts as no multi-part configuration has been provided

Answer 1

您正在发送带有需要Http POST的multipart / form数据编码的文件。在您的控制器中将其更改为如下所示。

@RequestMapping(value = "wyslij", method = RequestMethod.POST)

也在你的jsp中。

 <form method="post" action="http://localhost:8084/Hello/application/wyslij" enctype="multipart/form-data">
        <input type="file" name="file"/>
        <input type="submit"/>
    </form>

Answer 2

Chnaged和Controller现在是：

@Controller
public class UploadController 
{

    @RequestMapping(value = "wyslij", method = RequestMethod.POST)
    public String handleFormUpload(@RequestParam("file") MultipartFile file) throws IOException 
    {

        if (!file.isEmpty()) {
            byte[] bytes = file.getBytes();
            // store the bytes somewhere
           return "redirect:tak";
       } else 
        {
           return "redirect:nie";
       }
    }

}

和jsp：

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Wysylanie pliku</title>
    </head>

<body>
    <form method="post" action="http://localhost:8084/Hello/application/wyslij" enctype="multipart/form-data">
            <input type="file" name="file"/>
            <input type="submit"/>
        </form>
</body>


</html>

邮递员测试服务 GET测试的结果：

HTTP Status 405 - Request method 'GET' not supported

type Status report

message Request method 'GET' not supported

description The specified HTTP method is not allowed for the requested resource.

POST测试的结果：

HTTP Status 400 - Required MultipartFile parameter 'file' is not present

type Status report

message Required MultipartFile parameter 'file' is not present

description The request sent by the client was syntactically incorrect.

Spring MVC - 上传文件状态400 - 不存在所需的MultipartFile参数'file'

2 个答案: