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01-09、文件上传

发布于 2025-03-09 23:21:25 字数 18705 浏览 0 评论 0 收藏 0

先看一下 Servlet 是如何处理文件上传的：
Servlets - File Uploading
Java File Upload Example with Servlet 3.0 API

Spring MVC 下的处理是类似的。

下面展示一个简单的实现。

项目结构与源码

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/applicationContext.xml</param-value>
  </context-param>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>2</load-on-startup>
    <multipart-config>
      <file-size-threshold>1000000</file-size-threshold>
      <max-file-size>2000000</max-file-size>
      <max-request-size>4000000</max-request-size>
    </multipart-config>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
  <session-config>
    <session-timeout>
      30
    </session-timeout>
  </session-config>
  <welcome-file-list>
    <welcome-file>redirect.jsp</welcome-file>
  </welcome-file-list>
</web-app>

注意其中的限制文件大小的配置：

<multipart-config>
  <file-size-threshold>1000000</file-size-threshold>
  <max-file-size>2000000</max-file-size>
  <max-request-size>4000000</max-request-size>
</multipart-config>

applicationContext.xml

<?xml version='1.0' encoding='UTF-8' ?>
<!-- was: <?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:p="http://www.springframework.org/schema/p"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

</beans>

dispatcher-servlet.xml

<?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:p="http://www.springframework.org/schema/p"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:mvc="http://www.springframework.org/schema/mvc"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
     http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
     http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

  <context:component-scan base-package="me.letiantian.controller" />
  <context:component-scan base-package="me.letiantian.form" />
  <mvc:annotation-driven/>

  <bean id="multipartResolver"
      class="org.springframework.web.multipart.support.StandardServletMultipartResolver">
  </bean>

  <bean class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping"/>

  <bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
    <property name="mappings">
      <props>
        <prop key="index">indexController</prop>
      </props>
    </property>
  </bean>

  <bean id="viewResolver"
      class="org.springframework.web.servlet.view.InternalResourceViewResolver"
      p:prefix="/WEB-INF/jsp/"
      p:suffix=".jsp" />

  <bean name="indexController"
      class="org.springframework.web.servlet.mvc.ParameterizableViewController"
      p:viewName="index" />

   <mvc:resources mapping="/static/**" location="/static/"/>

</beans>

注意，这里增加了一个 multipart 解析器 StandardServletMultipartResolver ，用来处理上传的文件。 /static 是存放静态资源的目录， 我们也准备将上传的文件放到这个目录里。

UploadedFile.java

package me.letiantian.form;

import org.springframework.web.multipart.MultipartFile;

public class UploadedFile {
  private String fileName;
  private MultipartFile multipartFile;

  public String getFileName() {
    return fileName;
  }

  public void setFileName(String fileName) {
    this.fileName = fileName;
  }

  public MultipartFile getMultipartFile() {
    return multipartFile;
  }

  public void setMultipartFile(MultipartFile multipartFile) {
    this.multipartFile = multipartFile;
  }

}

HelloController.java

package me.letiantian.controller;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import me.letiantian.form.UploadedFile;
import org.springframework.web.bind.annotation.ModelAttribute;

import org.springframework.web.multipart.MultipartFile;

@Controller
@RequestMapping("/hello")
public class HelloController{

  @RequestMapping(value = "")
  public String index() {
    return "hello/index";
  }

  @RequestMapping(value = "/upload")
  public void output(@ModelAttribute UploadedFile uploadedFile,
      HttpServletRequest request,
      HttpServletResponse response) throws IOException {  
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    MultipartFile multiPartFile = uploadedFile.getMultipartFile();
    System.out.println("文件原始名称："+multiPartFile.getOriginalFilename());
    System.out.println("表单给定的文件名称："+uploadedFile.getFileName());

    try{
      System.out.println("上传目录："+request.getServletContext().getRealPath("/static"));
      File file = new File(request.getServletContext().getRealPath("/static"),
          uploadedFile.getFileName());
      multiPartFile.transferTo(file);  // 将文件写入本地
      out.println("<h2>上传成功</h2>");
    } catch (Exception ex) {
      System.out.println(""+ex.getMessage());
      out.println("<h2>上传失败</h2>");
    }
  }

}

注意，表单数据被绑定到了 uploadedFile 对象中。

hello/index.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
  </head>
  <body>
    <form method="post" action="${pageContext.request.contextPath}/hello/upload" enctype="multipart/form-data">
      指定文件名：<input type="text" name="fileName" /> <br/>
      选择文件： <input type="file" name="multipartFile" size="60"/> <br/>
      <input type="submit" value="Upload" />
    </form>
  </body>
</html>

测试程序

选择文件，指定名称：

上传成功：

查看上传的文件：

Tomcat 输出：

文件原始名称：01.png
表单给定的文件名称：1.png
上传目录：/data/Code/netbeans/Project_0109/build/web/static

资料

《Spring MVC 学习指南》 第 11 章先看一下 Servlet 是如何处理文件上传的：
Servlets - File Uploading
Java File Upload Example with Servlet 3.0 API

Spring MVC 下的处理是类似的。

下面展示一个简单的实现。

项目结构与源码

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/applicationContext.xml</param-value>
  </context-param>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>2</load-on-startup>
    <multipart-config>
      <file-size-threshold>1000000</file-size-threshold>
      <max-file-size>2000000</max-file-size>
      <max-request-size>4000000</max-request-size>
    </multipart-config>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
  <session-config>
    <session-timeout>
      30
    </session-timeout>
  </session-config>
  <welcome-file-list>
    <welcome-file>redirect.jsp</welcome-file>
  </welcome-file-list>
</web-app>

注意其中的限制文件大小的配置：

<multipart-config>
  <file-size-threshold>1000000</file-size-threshold>
  <max-file-size>2000000</max-file-size>
  <max-request-size>4000000</max-request-size>
</multipart-config>

applicationContext.xml

<?xml version='1.0' encoding='UTF-8' ?>
<!-- was: <?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:p="http://www.springframework.org/schema/p"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

</beans>

dispatcher-servlet.xml

<?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:p="http://www.springframework.org/schema/p"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:mvc="http://www.springframework.org/schema/mvc"
     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
     http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
     http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

  <context:component-scan base-package="me.letiantian.controller" />
  <context:component-scan base-package="me.letiantian.form" />
  <mvc:annotation-driven/>

  <bean id="multipartResolver"
      class="org.springframework.web.multipart.support.StandardServletMultipartResolver">
  </bean>

  <bean class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping"/>

  <bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
    <property name="mappings">
      <props>
        <prop key="index">indexController</prop>
      </props>
    </property>
  </bean>

  <bean id="viewResolver"
      class="org.springframework.web.servlet.view.InternalResourceViewResolver"
      p:prefix="/WEB-INF/jsp/"
      p:suffix=".jsp" />

  <bean name="indexController"
      class="org.springframework.web.servlet.mvc.ParameterizableViewController"
      p:viewName="index" />

   <mvc:resources mapping="/static/**" location="/static/"/>

</beans>

注意，这里增加了一个 multipart 解析器 StandardServletMultipartResolver ，用来处理上传的文件。 /static 是存放静态资源的目录， 我们也准备将上传的文件放到这个目录里。

UploadedFile.java

package me.letiantian.form;

import org.springframework.web.multipart.MultipartFile;

public class UploadedFile {
  private String fileName;
  private MultipartFile multipartFile;

  public String getFileName() {
    return fileName;
  }

  public void setFileName(String fileName) {
    this.fileName = fileName;
  }

  public MultipartFile getMultipartFile() {
    return multipartFile;
  }

  public void setMultipartFile(MultipartFile multipartFile) {
    this.multipartFile = multipartFile;
  }

}

HelloController.java

package me.letiantian.controller;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import me.letiantian.form.UploadedFile;
import org.springframework.web.bind.annotation.ModelAttribute;

import org.springframework.web.multipart.MultipartFile;

@Controller
@RequestMapping("/hello")
public class HelloController{

  @RequestMapping(value = "")
  public String index() {
    return "hello/index";
  }

  @RequestMapping(value = "/upload")
  public void output(@ModelAttribute UploadedFile uploadedFile,
      HttpServletRequest request,
      HttpServletResponse response) throws IOException {  
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    MultipartFile multiPartFile = uploadedFile.getMultipartFile();
    System.out.println("文件原始名称："+multiPartFile.getOriginalFilename());
    System.out.println("表单给定的文件名称："+uploadedFile.getFileName());

    try{
      System.out.println("上传目录："+request.getServletContext().getRealPath("/static"));
      File file = new File(request.getServletContext().getRealPath("/static"),
          uploadedFile.getFileName());
      multiPartFile.transferTo(file);  // 将文件写入本地
      out.println("<h2>上传成功</h2>");
    } catch (Exception ex) {
      System.out.println(""+ex.getMessage());
      out.println("<h2>上传失败</h2>");
    }
  }

}

注意，表单数据被绑定到了 uploadedFile 对象中。

hello/index.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
  </head>
  <body>
    <form method="post" action="${pageContext.request.contextPath}/hello/upload" enctype="multipart/form-data">
      指定文件名：<input type="text" name="fileName" /> <br/>
      选择文件： <input type="file" name="multipartFile" size="60"/> <br/>
      <input type="submit" value="Upload" />
    </form>
  </body>
</html>

测试程序

选择文件，指定名称：

上传成功：

查看上传的文件：

Tomcat 输出：

文件原始名称：01.png
表单给定的文件名称：1.png
上传目录：/data/Code/netbeans/Project_0109/build/web/static

资料

《Spring MVC 学习指南》 第 11 章

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