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  • JavaEE上传文件

    一、搭建环境

      1、本文是在搭建web环境下,上传功能的,可以参考下搭建web环境

      Maven配置SpringMVC4+Spring4+Mybatis3环境 

      2、需要添加上传文件依赖的jar包

            <!-- Apache Commons FileUpload -->
            <!-- http://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
            <dependency>
                <groupId>commons-fileupload</groupId>
                <artifactId>commons-fileupload</artifactId>
                <version>1.3.1</version>
            </dependency>
    
            <!-- Apache Commons IO -->
            <!-- http://mvnrepository.com/artifact/commons-io/commons-io -->
            <dependency>
                <groupId>commons-io</groupId>
                <artifactId>commons-io</artifactId>
                <version>2.4</version>
            </dependency>
    View Code

    二、使用SpringMVC上传文件

      1、在初始化Spring容器中添加上传配置

        <bean id="multipartResolver"
              class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            <!-- Maximum file size: 1MB -->
            <!-- 1MB = 125000 Byte -->
            <!--<property name="maxUploadSize" value="125000"/>-->
            <property name="defaultEncoding" value="utf-8"/>
        </bean>
    View Code

      2、新建FileUploadController类

    package com.moy.whymoy.test.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.ResponseBody;
    import org.springframework.web.multipart.MultipartFile;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.*;
    
    /**
     * [Project]:whymoy  <br/>
     * [Email]:moy25@foxmail.com  <br/>
     * [Date]:2018/3/13  <br/>
     * [Description]:  <br/>
     *
     * @author YeXiangYang
     */
    @Controller
    @RequestMapping("/upload")
    public class FileUploadController {
    
        @RequestMapping("/doUpload")
        @ResponseBody
        public String uploadFileHandler(HttpServletRequest request,
                                        HttpServletResponse response,
                                        @RequestParam(value = "files") MultipartFile[] files) {
    
            String realPath = request.getServletContext().getRealPath("upload");
            File uploadRootPath = new File(realPath);
            if (!uploadRootPath.exists()) {
                uploadRootPath.mkdirs();
            }
    
            StringBuilder sb = new StringBuilder();
    
            for (int i = 0; i < files.length; i++) {
                MultipartFile file = files[i];
                String originalFilename = file.getOriginalFilename();
                try {
                    File serverFile = new File(uploadRootPath, originalFilename);
                    try (BufferedInputStream bis = new BufferedInputStream(file.getInputStream());
                         BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(serverFile))) {
                        byte[] buffer = new byte[1024];
                        int len = 0;
                        while (-1 != (len = bis.read(buffer))) {
                            bos.write(buffer, 0, len);
                        }
                    }
                    sb.append("Upload File :").append(serverFile).append("
    ");
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return sb.toString();
        }
    }
    View Code

      3、在WEB-INF同级目录下,新建uploadFile.html(在同一站点下)

    <html>
    <head>
        <title>uploadOneFile</title>
    </head>
    <body>
    <form method="POST" action="upload/doUpload.do" enctype="multipart/form-data">
        File to upload: <input type="file" name="files"><br/>
        <input type="submit" value="Upload">
    </form>
    </body>
    </html>
    View Code

      4、运行tomcat7插件访问uploadFile.html页面,测试上传

    三、使用servlet上传

      1、新建UploadServlet类

    package com.moy.whymoy.test.servlet;
    
    import org.apache.commons.fileupload.FileItem;
    import org.apache.commons.fileupload.FileUploadException;
    import org.apache.commons.fileupload.disk.DiskFileItemFactory;
    import org.apache.commons.fileupload.servlet.ServletFileUpload;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.File;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.util.List;
    import java.util.Objects;
    
    /**
     * [Project]:whymoy  <br/>
     * [Email]:moy25@foxmail.com  <br/>
     * [Date]:2018/3/13  <br/>
     * [Description]:  <br/>
     *
     * @author YeXiangYang
     */
    @WebServlet(urlPatterns = "/upload/servlet")
    public class UploadServlet extends HttpServlet {
    
        // 上传目录
        private static String UPLOAD_DIR = "upload";
        // 默认编码
        private static String DEFAULT_ENCODING = "utf-8";
        // 内存临界值
        private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3;  // 3MB
        // 上传文件最大值
        private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
        // 请求最大值
        private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
            PrintWriter writer = resp.getWriter();
    
            if (!ServletFileUpload.isMultipartContent(req)) {
                writer.println("需要为类型为:enctype=multipart/form-data");
                return;
            }
    
            DiskFileItemFactory factory = new DiskFileItemFactory();
            factory.setSizeThreshold(MEMORY_THRESHOLD);
            ServletFileUpload servletFileUpload = new ServletFileUpload(factory);
    
            servletFileUpload.setSizeMax(MAX_REQUEST_SIZE);
            servletFileUpload.setFileSizeMax(MAX_FILE_SIZE);
            servletFileUpload.setHeaderEncoding(DEFAULT_ENCODING);
    
            String realPath = req.getServletContext().getRealPath(UPLOAD_DIR);
            File uploadRootPath = new File(realPath);
            if (!uploadRootPath.exists()) {
                uploadRootPath.mkdirs();
            }
    
            try {
                List<FileItem> fileItems = servletFileUpload.parseRequest(req);
                if (Objects.nonNull(fileItems)) {
                    for (FileItem eachItem : fileItems) {
                        if (!eachItem.isFormField()) {
                            String fileName = new File(eachItem.getName()).getName();
                            File serverFile = new File(uploadRootPath, fileName);
                            eachItem.write(serverFile);
                            writer.println("Upload File :" + serverFile);
                        }
                    }
                }
            } catch (FileUploadException e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    View Code

      2、在WEB-INF同级目录下,新建servletUploadFile.html(在同一站点下)

    <html>
    <head>
        <title>uploadOneFile</title>
    </head>
    <body>
    <form method="POST" action="upload/servlet" enctype="multipart/form-data">
        File to upload: <input type="file" name="files"><br/>
        <input type="submit" value="Upload">
    </form>
    </body>
    </html>
    View Code

      3、运行tomcat7插件访问servletUploadFile.html页面,测试上传

    四、异步上传

      1、在WEB-INF同级目录下,添加jquery.js库和新建ajax.html(在同一站点下)

    <!DOCTYPE html>
    <html>
    <head>
        <title>test</title>
        <script type="text/javascript" src="./jquery.js"></script>
    </head>
    <body>
        <form  id="form1" method="POST" action="http://192.168.182.130:8080/whymoy/upload/servlet" enctype="multipart/form-data">
        File to upload: <input type="file" name="files"><br/>
            <input type="submit" value="表单同步上传">
        </form><br/>
    
        <input id="ajaxUpload" type="button" value="异步上传"> <br/>
        <div id="result" style="color: red">
            
        </div>
    
        <script type="text/javascript">
            $(function(){
                $("#ajaxUpload").click(function(){
                    $.ajax({
                        url:"http://192.168.182.130:8080/whymoy/upload/doUpload.do",
                        type: 'POST',
                        cache: false,
                        data: new FormData($('#form1')[0]),
                        processData: false,
                        contentType: false,
                        success:function(data){
                            $("#result").text(data);
                        }
                    })
                });
            });
        </script>
    </body>
    </html>
    View Code

      2、运行tomcat7插件访问ajax.html页面,测试上传

    五、跨域异步上传

      1、第四步是可以满足异步上传的,只是进入不了回调函数,想要进入回调函数,可以响应时添加对应的响应头,可以参考

      JavaEE从服务器端解决Ajax跨域问题

     六、也可以直接使用httpClient,获取文件流,直接上传

      1、添加依赖

            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.3</version>
            </dependency>
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpmime</artifactId>
                <version>4.5.3</version>
            </dependency>
    View Code

      2、测试代码

    package com.moy.whymoy.test;
    
    import org.apache.http.HttpEntity;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.entity.mime.MultipartEntityBuilder;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.apache.http.util.EntityUtils;
    
    import java.io.File;
    import java.io.IOException;
    
    /**
     * [Project]:whymoy  <br/>
     * [Email]:moy25@foxmail.com  <br/>
     * [Date]:2018/3/14  <br/>
     * [Description]:  <br/>
     *
     * @author YeXiangYang
     */
    public class Main {
    
        public static void main(String[] args) throws IOException {
            try (CloseableHttpClient httpClient = HttpClients.createDefault();) {
                File file = new File("pom.xml");
                MultipartEntityBuilder entityBuilder = MultipartEntityBuilder.create();
                entityBuilder.addBinaryBody("files", file);
                HttpEntity httpEntity = entityBuilder.build();
    
                String uploadUrl = "http://localhost:8080/whymoy/upload/doUpload.do";
                HttpPost httpPost = new HttpPost(uploadUrl);
                httpPost.setEntity(httpEntity);
    
                CloseableHttpResponse response = httpClient.execute(httpPost);
                String result = EntityUtils.toString(response.getEntity());
                System.out.println(result);
            }
        }
    }
    View Code

    yexiangyang

    moyyexy@gmail.com


     

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  • 原文地址:https://www.cnblogs.com/moy25/p/8570613.html
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