HttpClient工具类

public class HttpClientUtil {
private static Logger logger = LoggerFactory.getLogger(HttpClientUtil.class);

public static String doGet(String url, Map<String, String> param) {
    // 创建Httpclient对象
    CloseableHttpClient httpclient = HttpClients.createDefault();
    String resultString = "";
    CloseableHttpResponse response = null;
    try {
        // 创建uri
        URIBuilder builder = new URIBuilder(url);
        if (param != null) {
            for (String key : param.keySet()) {
                builder.addParameter(key, param.get(key));
            }
        }
        URI uri = builder.build();
        logger.debug("whole url:" + uri);
        // 创建http GET请求
        HttpGet httpGet = new HttpGet(uri);
        // 执行请求
        response = httpclient.execute(httpGet);
        // 判断返回状态是否为200
        if (response.getStatusLine().getStatusCode() == 200) {
            resultString = EntityUtils.toString(response.getEntity(), "UTF-8");
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (response != null) {
                response.close();
            }
            httpclient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return resultString;
}
public static String doGet(String url) {
    return doGet(url, null);
}
/**
 * doPostByJson
 * @param url
 * @param json
 * @return
 */
public static String doPostByJson(String url, String json, String chartSet) {
    String defalutChartSet = "UTF-8";
    if (chartSet != null) {
        defalutChartSet = chartSet;
    }
    // 创建Httpclient对象
    CloseableHttpClient httpClient = HttpClients.createDefault();
    CloseableHttpResponse response = null;
    String resultString = "";
    try {
        // 创建Http Post请求
        HttpPost httpPost = new HttpPost(url);
        // 创建请求内容
        StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
        entity.setContentEncoding(defalutChartSet);
        httpPost.setEntity(entity);
        // 执行http请求
        response = httpClient.execute(httpPost);
        resultString = EntityUtils.toString(response.getEntity(), defalutChartSet);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            response.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return resultString;
}
/**
 *
 * @param url
 * @param param
 * @param chartSet
 * @return
 */
public static String doPost(String url, Map<String, String> param, String chartSet) {
    String defalutChartSet = "UTF-8";
    if (chartSet != null) {
        defalutChartSet = chartSet;
    }
    // 创建Httpclient对象
    CloseableHttpClient httpClient = HttpClients.createDefault();
    CloseableHttpResponse response = null;
    String resultString = "";
    try {
        // 创建Http Post请求
        HttpPost httpPost = new HttpPost(url);
        // 创建参数列表
        if (param != null) {
            List<NameValuePair> paramList = new ArrayList<>();
            for (String key : param.keySet()) {
                paramList.add(new BasicNameValuePair(key, param.get(key)));
            }
            // 模拟表单
            UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList, defalutChartSet);
            httpPost.setEntity(entity);
        }
        // 执行http请求
        response = httpClient.execute(httpPost);
        resultString = EntityUtils.toString(response.getEntity(), defalutChartSet);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (response != null) {
                response.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return resultString;
}
public static String doPostByFile(String url, File file, String termSeq) {
    String resultString = "";
    CloseableHttpClient httpClient = null;
    CloseableHttpResponse response = null;
    try {
        httpClient = HttpClients.createDefault();
        // 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(url);
        // 把文件转换成流对象FileBody
        FileBody bin = new FileBody(file);
        StringBody termSeqStr = new StringBody(termSeq, ContentType.create(
                "text/plain", Consts.UTF_8));
        HttpEntity reqEntity = MultipartEntityBuilder.create()
                // 相当于<input type="file" name="file"/>
                .addPart("file", bin)
                // 相当于<input type="text" name="userName" value=userName>
                .addPart("termSeq", termSeqStr)

// .addPart(“pass”, password)
.build();

        httpPost.setEntity(reqEntity);
        // 发起请求 并返回请求的响应
        response = httpClient.execute(httpPost);
        logger.info("The response value of token:" + response.getFirstHeader("token"));
        System.out.println("The response value of token:" + response.getFirstHeader("token"));
        // 获取响应对象
        HttpEntity resEntity = response.getEntity();
        if (resEntity != null) {
            // 打印响应长度
            logger.info("Response content length: " + resEntity.getContentLength());
            System.out.println("Response content length: " + resEntity.getContentLength());
            // 打印响应内容
            resultString = EntityUtils.toString(resEntity, Charset.forName("UTF-8"));
        }
        // 销毁
        EntityUtils.consume(resEntity);
        return resultString;
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (response != null) {
                response.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            if (httpClient != null) {
                httpClient.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return resultString;
}
/**
 * 
 * @param url
 * @param param
 * @return
 */
public static String doPost(String url, Map<String, String> param) {
    return doPost(url, param, null);
}
/**
 *
 * @param url
 * @return
 */
public static String doPost(String url) {
    return doPost(url, null);
}

}