HttpClient4 基本操作

文件上传

/**  * 上传文件  *   * @throws ParseException  * @throws IOException  */  public static void postFile() throws ParseException, IOException {      CloseableHttpClient httpClient = HttpClients.createDefault();      try {          // 要上传的文件的路径          String filePath = new String("C:\\Users\\zz\\Desktop\\diqu.png");          // 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(                  "http://xx.xx.xx.xxs:8081/auth_center/upload");          // 把文件转换成流对象FileBody          File file = new File(filePath);          FileBody bin = new FileBody(file);          /*StringBody uploadFileName = new StringBody("my.png",                 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 {              // 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();      }  }  

文件下载

/**  * 下载文件  *   * @param url  *            http://www.xxx.com/img/333.jpg  * @param destFileName  *            xxx.jpg/xxx.png/xxx.txt  * @throws ClientProtocolException  * @throws IOException  */  public static void getFile(String url, String destFileName)          throws ClientProtocolException, IOException {      // 生成一个httpclient对象      CloseableHttpClient httpclient = HttpClients.createDefault();      HttpGet httpget = new HttpGet(url);      HttpResponse response = httpclient.execute(httpget);      HttpEntity entity = response.getEntity();      InputStream in = entity.getContent();      File file = new File(destFileName);      try {          FileOutputStream fout = new FileOutputStream(file);          int l = -1;          byte[] tmp = new byte[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();  }  

读取压缩文件

public static void readZipFile(String file) throws Exception {         ZipFile zf = new ZipFile(file);         InputStream in = new BufferedInputStream(new FileInputStream(file));         ZipInputStream zin = new ZipInputStream(in);         ZipEntry ze;         while ((ze = zin.getNextEntry()) != null) {             if (ze.isDirectory()) {           } else {                 System.err.println("file - " + ze.getName() + " : "                         + ze.getSize() + " bytes");                 long size = ze.getSize();                 if (size > 0) {                     BufferedReader br = new BufferedReader(                             new InputStreamReader(zf.getInputStream(ze)));                     String line;                     while ((line = br.readLine()) != null) {                         System.out.println(line);                     }                     br.close();                 }                 System.out.println();             }         }         zin.closeEntry();     }  

Post Json数据

HttpPost httpPost = new HttpPost(url);StringEntity stringEntity = new StringEntity(json.toString());stringEntity.setContentType("application/json");httpPost.setEntity(stringEntity);

示例：

public static String httpPostWithJSON(String url) throws Exception {        HttpPost httpPost = new HttpPost(url);        CloseableHttpClient client = HttpClients.createDefault();        String respContent = null;//        json方式        JSONObject jsonParam = new JSONObject();          jsonParam.put("name", "admin");        jsonParam.put("pass", "123456");        StringEntity entity = new StringEntity(jsonParam.toString(),"utf-8");//解决中文乱码问题            entity.setContentEncoding("UTF-8");            entity.setContentType("application/json");            httpPost.setEntity(entity);        System.out.println();//        表单方式//        List<BasicNameValuePair> pairList = new ArrayList<BasicNameValuePair>(); //        pairList.add(new BasicNameValuePair("name", "admin"));//        pairList.add(new BasicNameValuePair("pass", "123456"));//        httpPost.setEntity(new UrlEncodedFormEntity(pairList, "utf-8"));           HttpResponse resp = client.execute(httpPost);        if(resp.getStatusLine().getStatusCode() == 200) {            HttpEntity he = resp.getEntity();            respContent = EntityUtils.toString(he,"UTF-8");        }        return respContent;    }    public static void main(String[] args) throws Exception {        String result = httpPostWithJSON("http://localhost:8080/hcTest2/Hc");        System.out.println(result);    }