[转]httpclient 上传文件、下载文件

用httpclient4.3 post方式推送文件到服务端  
准备：httpclient-4.3.3.jar；httpcore-4.3.2.jar；httpmime-4.3.3.jar
/**
 * 上传文件
 * @throws  ParseException
 * @throws  IOException
 */
publicstaticvoidpostFile()throwsParseException, IOException{
    CloseableHttpClient httpClient = HttpClients.createDefault();
    try{
        // 要上传的文件的路径
        String filePath =newString("F:/pic/001.jpg");
        // 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 =newHttpPost(
                "http://localhost:8080/xxx/xxx.action");
        // 把文件转换成流对象FileBody
        File file =newFile(filePath);
        FileBody bin =newFileBody(file);
        StringBody uploadFileName =newStringBody(
                "把我修改成文件名称", ContentType.create(
                        "text/plain", Consts.UTF_8));
        //以浏览器兼容模式运行，防止文件名乱码。
           HttpEntity reqEntity = MultipartEntityBuilder.create().setMode(HttpMultipartMode.BROWSER_COMPATIBLE)
                .addPart("uploadFile", bin)//uploadFile对应服务端类的同名属性<File类型>
                .addPart("uploadFileName", uploadFileName)//uploadFileName对应服务端类的同名属性<String类型>
                .setCharset(CharsetUtils.get("UTF-8")).build();

        httpPost.setEntity(reqEntity);

        System.out.println("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{
            System.out.println("----------------------------------------");
            // 打印响应状态
            System.out.println(response.getStatusLine());
            // 获取响应对象
            HttpEntity resEntity = response.getEntity();
            if(resEntity !=null) {
                // 打印响应长度
                System.out.println("Response content length: "
                        + resEntity.getContentLength());
                // 打印响应内容
                System.out.println(EntityUtils.toString(resEntity,
                        Charset.forName("UTF-8")));
            }
            // 销毁
            EntityUtils.consume(resEntity);
        }finally{
            response.close();
        }
    }finally{
        httpClient.close();
    }
}

 /**
 * 下载文件
 * @param  url
 * @param  destFileName   xxx.jpg/xxx.png/xxx.txt
 * @throws  ClientProtocolException
 * @throws IOException
 */
publicstaticvoidgetFile(String url, String destFileName)
        throwsClientProtocolException, IOException {
    // 生成一个httpclient对象
    CloseableHttpClient httpclient = HttpClients.createDefault();
    HttpGet httpget =newHttpGet(url);
    HttpResponse response = httpclient.execute(httpget);
    HttpEntity entity = response.getEntity();
    InputStream in = entity.getContent();
    File file =newFile(destFileName);
    try{
        FileOutputStream fout =newFileOutputStream(file);
        intl = -1;
        byte[] tmp =newbyte[1024];
        while((l = in.read(tmp)) != -1) {
            fout.write(tmp,0, l);
            // 注意这里如果用OutputStream.write(buff)的话，图片会失真，大家可以试试
        }
        fout.flush();
        fout.close();
    }finally{
        // 关闭低层流。
        in.close();
    }
    httpclient.close();
}