首先引入依賴

    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.6</version>
    </dependency>

private final int timeOut = 500;
public String queryString(String code) {

        // 獲得Http客戶端(可以理解為:先有一個瀏覽器;注意:實際上HttpClient與瀏覽器是不一樣的)
 

        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        // 引數
        StringBuffer params = new StringBuffer();
        try {
            // 字元資料最好encoding下;這樣一來，某些特殊字元才能傳過去(如:某人的名字就是“&”,不encoding的話,傳不過去)
            params.append("code=" + URLEncoder.encode(code, "utf-8"));
        } 
 
catch (UnsupportedEncodingException e1) {
            e1.printStackTrace();
        }
        // 建立Get請求
        HttpGet httpGet = new HttpGet(192.168.xx.xx:port/xx/queryString);
        // 響應模型
        CloseableHttpResponse response = null;
        try {
            // 配置資訊
            RequestConfig requestConfig = RequestConfig.custom()
                    
 
// 設定連線超時時間(單位毫秒)
                    .setConnectTimeout(timeOut)
                    // 設定請求超時時間(單位毫秒)
                    .setConnectionRequestTimeout(timeOut)
                    // socket讀寫超時時間(單位毫秒)
                    .setSocketTimeout(timeOut)
                    // 設定是否允許重定向(預設為true)
                    .setRedirectsEnabled(true).build();
            // 將上面的配置資訊 運用到這個Get請求裡
            httpGet.setConfig(requestConfig);
            // 由客戶端執行(傳送)Get請求
            response = httpClient.execute(httpGet);
            // 從響應模型中獲取響應實體
            HttpEntity responseEntity = response.getEntity();
            System.out.println("響應狀態為:" + response.getStatusLine());
            if (responseEntity != null) {
                System.out.println("響應內容長度為:" + responseEntity.getContentLength());
                System.out.println("響應內容為:" + EntityUtils.toString(responseEntity));
                String json = EntityUtils.toString(responseEntity);
                String result = JsonUtil.fromJson(json, String.class);
                if(null!= result ){
                    return result ;
                }
            } else {
                return null;
            }
        } catch (Exception e) {
            //todo 此處做異常處理返回
            //e.printStackTrace();return ("與資料服務連線異常!");
        } finally {
            closeClient(httpClient, response);
        }
        return null;
    }