【Java Web开发学习】Spring MVC文件上传

【Java Web开发学习】Spring MVC文件上传

转载：https://www.cnblogs.com/yangchongxing/p/9290489.html

文件上传有两种实现方式，都比较简单

方式一、使用StandardServletMultipartResolver

依赖Servlet3.0对Multipart请求的支持，需要MultipartConfigElement配置请求的相关参数

code-base方式

@Bean
public MultipartResolver multipartResolver() {
    return new StandardServletMultipartResolver();
}

通过MultipartConfigElement配置上传临时路径，上传文件大小，上传请求的大小。

通过重载protected void customizeRegistration(ServletRegistration.Dynamic registration)方法实现，看代码

package cn.ycx.web.config;

import java.io.IOException;
import java.util.Properties;

import javax.servlet.MultipartConfigElement;
import javax.servlet.ServletRegistration;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class ServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    
    // 将一个或多个路径映射到DispatcherServlet上
    @Override
    protected String[] getServletMappings() {
        return new String[] {"/"};
    }
    
    // 返回的带有@Configuration注解的类将会用来配置ContextLoaderListener创建的应用上下文中的bean
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[] {RootConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[] {ServletConfig.class};
    }
    @Override
    protected void customizeRegistration(ServletRegistration.Dynamic registration) {
        // 上传文件的临时目录
        String location = "/tmp";
        // 上传文件的最大容量
        long maxFileSize = 3145728;
        // 请求的最大容量
        long maxRequestSize = 3145728;
        // 上传的最小临界值，大于该值才会被写入文件保存
        // int fileSizeThreshold = 0;
        try {
            Properties prop = new Properties();
            prop.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("upload.properties"));
            location = prop.getProperty("temporary.location");
            maxFileSize = Long.parseLong(prop.getProperty("max.file.size"));
            maxRequestSize = Long.parseLong(prop.getProperty("max.request.size"));
        } catch (IOException e) {}
        // 文件上传配置
        registration.setMultipartConfig(new MultipartConfigElement(location, maxFileSize, maxRequestSize, 0));
        // 没有找到处理的请求抛出异常
        boolean done = registration.setInitParameter("throwExceptionIfNoHandlerFound", "true");
        if(!done) throw new RuntimeException("设置异常(throwExceptionIfNoHandlerFound)");
    }
}

xml-base方式

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

web.xml配置DispatcherServlet初始化参数

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    ...省略...
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet
        </servlet-class>
        <init-param>  
            <param-name>contextConfigLocation</param-name>  
            <param-value>classpath:dispatcher-servlet.xml</param-value>  
        </init-param>  
        <load-on-startup>0</load-on-startup>
        <multipart-config>
            <!--临时文件的目录-->
            <location>E:/tmp</location>
            <!-- 上传文件最大3M -->
            <max-file-size>3145728</max-file-size>
            <!-- 上传文件整个请求不超过3M -->
            <max-request-size>3145728</max-request-size>
        </multipart-config>
    </servlet>
    ...省略...
</web-app>

方式二、使用CommonsMultipartResolver

依赖 commons-fileupload.jar 和 commons-io.jar。上传临时路径，文件大小都在对象中设置。

code-base方式

@Bean
public MultipartResolver multipartResolver() throws IOException {
    CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
    multipartResolver.setUploadTempDir(new FileSystemResource(config.uploadTemporaryLocation()));
    multipartResolver.setMaxUploadSize(config.uploadMaxFileSize());
    multipartResolver.setMaxInMemorySize(0);
    return multipartResolver;
}

xml-base方式

<!-- 上传文件 -->  
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="defaultEncoding" value="utf-8"/>
    <!-- 最大内存大小 -->
    <property name="maxInMemorySize" value="10240"/>
    <!-- 最大文件大小，-1为不限制大小 -->
    <property name="maxUploadSize" value="-1"/>
</bean>

示例代码：

实现了核心部分仅供参考。

package cn.ycx.web.controller;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.springframework.beans.factory.annotation.Autowired;
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.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;

import cn.ycx.web.config.PropertyConfig;


/**
 * 上传
 * @author 杨崇兴 2018-07-09
 */
@Controller
@RequestMapping("/upload")
public class UploadController extends BaseController {
    /**
     * 属性配置
     */
    @Autowired
    private PropertyConfig config;
    
    @RequestMapping(value="/image", method=RequestMethod.POST, produces="application/json;charset=UTF-8")
    public String image(@RequestParam(value = "imageFile", required = false) MultipartFile multipartFile) {
        try {
            String serverPath = config.uploadImageSavePath() + new SimpleDateFormat("yyyy/MM/dd/").format(new Date());
            File serverPathFile = new File(serverPath);
            //目录不存在则创建
            if (!serverPathFile.exists()) {
                serverPathFile.mkdirs();
            }
            String fileName = multipartFile.getOriginalFilename();
            multipartFile.transferTo(new File(serverPath + fileName));
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "success";
    }
}

<!DOCTYPE html>
<html lang="zh" xmlns:th="http://www.thymeleaf.org">
    <head>
        <meta charset="UTF-8">
        <title>上传</title>
    </head>
<body>
<form action="/ycxcode/upload/image" method="post" enctype="multipart/form-data">
    <input type="text" name="discription" value="discription"/>
    <input type="file" name="imageFile">
    <input type="submit" value="submit"/>
</form>
</body>
</html>