[轉]httpclient 上傳文件、下載文件

用httpclient4.3 post方式推送文件到服務端  
準備：httpclient-4.3.3.jar；httpcore-4.3.2.jar；httpmime-4.3.3.jar
/**
 * 上傳文件
 * @throws  ParseException
 * @throws  IOException
 */   
publicstaticvoidpostFile()throwsParseException, IOException{
    CloseableHttpClient httpClient = HttpClients.createDefault();
    try{
        // 要上傳的文件的路徑
        String filePath =newString("F:/pic/001.jpg");
        // 把一個普通參數和文件上傳給下面這個地址 是一個servlet
        HttpPost httpPost =newHttpPost(
                "http://localhost:8080/xxx/xxx.action");
        // 把文件轉換成流對象FileBody
        File file =newFile(filePath);
        FileBody bin =newFileBody(file); 
        StringBody uploadFileName =newStringBody(
                "把我修改爲文件名稱", ContentType.create(
                        "text/plain", Consts.UTF_8));
        //以瀏覽器兼容模式運行，防止文件名亂碼。 
           HttpEntity reqEntity = MultipartEntityBuilder.create().setMode(HttpMultipartMode.BROWSER_COMPATIBLE)
                .addPart("uploadFile", bin)//uploadFile對應服務端類的同名屬性<File類型>
                .addPart("uploadFileName", uploadFileName)//uploadFileName對應服務端類的同名屬性<String類型>
                .setCharset(CharsetUtils.get("UTF-8")).build();
 
        httpPost.setEntity(reqEntity);
 
        System.out.println("發起請求的頁面地址 "+ httpPost.getRequestLine());
        // 發起請求 並返回請求的響應
        CloseableHttpResponse response = httpClient.execute(httpPost);
        try{
            System.out.println("----------------------------------------");
            // 打印響應狀態
            System.out.println(response.getStatusLine());
            // 獲取響應對象
            HttpEntity resEntity = response.getEntity();
            if(resEntity !=null) {
                // 打印響應長度
                System.out.println("Response content length: "
                        + resEntity.getContentLength());
                // 打印響應內容
                System.out.println(EntityUtils.toString(resEntity,
                        Charset.forName("UTF-8")));
            }
            // 銷燬
            EntityUtils.consume(resEntity);
        }finally{
            response.close();
        }
    }finally{
        httpClient.close();
    }
}
 
 /**
 * 下載文件
 * @param  url
 * @param  destFileName   xxx.jpg/xxx.png/xxx.txt
 * @throws  ClientProtocolException
 * @throws IOException
 */
publicstaticvoidgetFile(String url, String destFileName)
        throwsClientProtocolException, IOException {
    // 生成一個httpclient對象
    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);
            // 注意這裏若是用OutputStream.write(buff)的話，圖片會失真，你們能夠試試
        }
        fout.flush();
        fout.close();
    }finally{
        // 關閉低層流。
        in.close();
    }
    httpclient.close();
}