java实现Multipart/form-data

maven

新的maven和先前的版本的API不同

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

上传

package uploadTest;import java.io.File;import java.io.IOException;import java.nio.charset.Charset;import java.util.HashMap;import java.util.Map;import java.util.Set;import org.apache.http.Consts;import org.apache.http.HttpEntity;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpPost;import org.apache.http.entity.ContentType;import org.apache.http.entity.mime.MultipartEntityBuilder;import org.apache.http.entity.mime.content.FileBody;import org.apache.http.entity.mime.content.StringBody;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.util.EntityUtils;import org.slf4j.Logger;import org.slf4j.LoggerFactory;public class UploadTest {    public static Map<String,Object> uploadFileByHTTP(File postFile,String postUrl,Map<String,String> postParam){        Logger log = LoggerFactory.getLogger(UploadTest.class);        Map<String,Object> resultMap = new HashMap<String,Object>();        CloseableHttpClient httpClient = HttpClients.createDefault();        try{            //把一个普通参数和文件上传给下面这个地址    是一个servlet            HttpPost httpPost = new HttpPost(postUrl);            //把文件转换成流对象FileBody            FileBody fundFileBin = new FileBody(postFile);            //设置传输参数            MultipartEntityBuilder multipartEntity = MultipartEntityBuilder.create();            multipartEntity.addPart(postFile.getName(), fundFileBin);//相当于<input type="file" name="media"/>            //设计文件以外的参数            Set<String> keySet = postParam.keySet();            for (String key : keySet) {                //相当于<input type="text" name="name" value=name>                multipartEntity.addPart(key, new StringBody(postParam.get(key), ContentType.create("text/plain", Consts.UTF_8)));            }            HttpEntity reqEntity =  multipartEntity.build();            httpPost.setEntity(reqEntity);            log.info("发起请求的页面地址 " + httpPost.getRequestLine());            //发起请求   并返回请求的响应            CloseableHttpResponse response = httpClient.execute(httpPost);            try {                log.info("----------------------------------------");                //打印响应状态                //log.info(response.getStatusLine());                resultMap.put("statusCode", response.getStatusLine().getStatusCode());                //获取响应对象                HttpEntity resEntity = response.getEntity();                if (resEntity != null) {                    //打印响应长度                    log.info("Response content length: " + resEntity.getContentLength());                    //打印响应内容                    resultMap.put("data", EntityUtils.toString(resEntity,Charset.forName("UTF-8")));                }                //销毁                EntityUtils.consume(resEntity);            } catch (Exception e) {                e.printStackTrace();            } finally {                response.close();            }        } catch (ClientProtocolException e1) {            e1.printStackTrace();        } catch (IOException e1) {            e1.printStackTrace();        } finally{            try {                httpClient.close();            } catch (IOException e) {                e.printStackTrace();            }        }        log.info("uploadFileByHTTP result:"+resultMap);        return resultMap;    }    //测试    public static void main(String args[]) throws Exception {        //要上传的文件的路径        String filePath = "d:/test0.jpg";        String postUrl  = "http://localhost:8080/v1/contract/addContract.do";        Map<String,String> postParam = new HashMap<String,String>();        postParam.put("shopId", "15");        File postFile = new File(filePath);        Map<String,Object> resultMap = uploadFileByHTTP(postFile,postUrl,postParam);        System.out.println(resultMap);    }}

接收

@Path("addContract.do")@Consumes(MediaType.MULTIPART_FORM_DATA)@Produces(MediaType.TEXT_HTML)public String addContract(@Context HttpServletRequest request, @Context HttpServletResponse response){    try{        //这里根据业务做修改        Contract contract = new Contract();        //重点是调用saveFile方法        UploadResult uploadResult = saveFile(request);        contract.setShopId(Integer.valueOf(uploadResult.getParamMap().get("shopId")));        contract.setContractUrl(uploadResult.getFilePath());        Boolean success = contractService.addContract(contract);        return JSON.toJSONString(RespApi.buildResp(200, "success", success));    } catch (ContractExeption contractExeption) {        log.warn(ExceptionUtils.getStackTrace(contractExeption));        return JSON.toJSONString(RespApi.buildResp(400, "fail to add contract", false));    }}public UploadResult saveFile(HttpServletRequest request) {    Map<String,String> resultMap = new HashMap<>();    String fileName = "";    try {        if (ServletFileUpload.isMultipartContent(request)) {            FileItemFactory factory = new DiskFileItemFactory();        //如果没以下两行设置的话，上传大的 文件 会占用 很多内存，        //设置暂时存放的 存储室 , 这个存储室，可以和 最终存储文件 的目录不同        /**         * 原理 它是先存到 暂时存储室，然后在真正写到 对应目录的硬盘上，         * 按理来说 当上传一个文件时，其实是上传了两份，第一个是以 .tem 格式的         * 然后再将其真正写到 对应目录的硬盘上         */        //这个tempDir需要自己设置        File tempF = new File(tempDir);        if (!tempF.exists()) {            tempF.mkdirs();        }        factory.setRepository(tempF);        //设置 缓存的大小，当上传文件的容量超过该缓存时，直接放到 暂时存储室        factory.setSizeThreshold(1024 * 1024);        //高水平的API文件上传处理        ServletFileUpload upload = new ServletFileUpload(factory);        List<FileItem> items = null;        try {            items = upload.parseRequest(request);        } catch (FileUploadException e) {            e.printStackTrace();        }        if (items != null) {            Iterator<FileItem> iter = items.iterator();            while (iter.hasNext()) {                FileItem item = iter.next();                //属性字段                if (item.isFormField()) {                    //获取表单的属性名字                    String name = item.getFieldName();                    String value = item.getString();                    resultMap.put(name,value);                }                //文件                if (!item.isFormField() && item.getSize() > 0) {                 //可以得到流                 InputStream in = item.getInputStream();                    fileName = processFileName(item.getName());                    try {                        String basePath = getRootPath();                        String types = "pic";                        String date = DateUtil.getNowDateStr(DateUtil.TO_DAY);                        String realPath = basePath + File.separator + types + File.separator + date                                + File.separator;                        //String realPath = basePath + File.separator + types + File.separator + date                        //        + File.separator;                        System.out.println(realPath);                        File file1 = new File(realPath);                        if (!file1.exists()) {                            file1.mkdirs();                        }                        String name = UUID.randomUUID().toString() + ".jpg";                        fileName = types + File.separator + date + File.separator + name;                        File files = new File(realPath + name);                        item.write(files);                    } catch (Exception e) {                        e.printStackTrace();                    }                    }                }            }        }    } catch (Exception e) {    }    UploadResult uploadResult = new UploadResult();    uploadResult.setFilePath(fileName);    uploadResult.setParamMap(resultMap);    return uploadResult;}//返回结果的包装类public class UploadResult {    private String filePath;    private Map<String,String> paramMap;    public String getFilePath() {        return filePath;    }    public void setFilePath(String filePath) {        this.filePath = filePath;    }    public Map<String, String> getParamMap() {        return paramMap;    }    public void setParamMap(Map<String, String> paramMap) {        this.paramMap = paramMap;    }}

参考

http://lushuifa.iteye.com/blog/2382115

说明：
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http://blog.csdn.net/antony9118/article/details/78226426