java 发送 HTTP 请求

一.发送 HTTP GET 请求

    import org.apache.commons.lang.StringUtils;
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpStatus;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.entity.StringEntity;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClientBuilder;
    import org.apache.http.util.EntityUtils;
    import org.apache.http.HttpResponse;

    /**
     * 发送 HTTP GET 请求
     * 
     * @param url
     * @return
     */
    public String httpGet(String url) {

        String result = "";

        // 创建HttpClientBuilder
        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();

        // HttpClient
        CloseableHttpClient closeableHttpClient = httpClientBuilder.build();

        HttpGet httpGet = null;
        HttpResponse httpResponse = null;
        HttpEntity httpEntity = null;
        httpGet = new HttpGet(url);

        try {

            httpResponse = closeableHttpClient.execute(httpGet);

            if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                httpEntity = httpResponse.getEntity();
                if (httpEntity != null) {
                    result = EntityUtils.toString(httpEntity);
                }
            }

            // 关闭连接
            closeableHttpClient.close();

        } catch (IOException e) {
            logger.error(e.getMessage(), e);
        }

        return result;

    }

    /**
     * 执行一个HTTP GET请求，返回请求响应的HTML
     * 
     * @param url
     *            请求的URL地址
     * @param queryString
     *            请求的查询参数,可以为null
     * @return 返回请求响应的HTML
     */
    public String doGet(String url, String queryString) {
        String result = "";
        HttpClient client = new HttpClient();
        HttpMethod method = new GetMethod(url);
        try {

            if (StringUtils.isNotBlank(queryString))
                method.setQueryString(URIUtil.encodeQuery(queryString));
            client.executeMethod(method);
            if (method.getStatusCode() == HttpStatus.SC_OK) {
                result = method.getResponseBodyAsString();
            }

        } catch (IOException e) {
            logger.error(e.getMessage(), e);
        } finally {
            method.releaseConnection();
        }

        return result;
    }

二.发送HTTP POST 请求

    import org.apache.commons.lang.StringUtils;
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpStatus;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.entity.StringEntity;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClientBuilder;
    import org.apache.http.util.EntityUtils;
    import org.apache.http.HttpResponse;
    
     /**
     * 发送POST请求
     * @return
     * @throws IOException
     */
    private static String httpPost(String url,String condition) throws IOException {

        String result = "";

        // 创建HttpClientBuilder
        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
        CloseableHttpClient closeableHttpClient = null;
        CloseableHttpResponse closeableHttpResponse = null;

        HttpEntity httpEntity = null;
        HttpPost httpPost = new HttpPost(builderUrl.toString());
        StringEntity stringEntity = null;

        try {

            // 添加http头信息
            stringEntity = new StringEntity(condition, "utf-8");// 解决中文乱码问题
            stringEntity.setContentEncoding("UTF-8");
            stringEntity.setContentType("application/json");
            httpPost.setEntity(stringEntity);

            closeableHttpClient = httpClientBuilder.build();
            closeableHttpResponse = closeableHttpClient.execute(httpPost);

            if (closeableHttpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                httpEntity = closeableHttpResponse.getEntity();
                if (httpEntity != null) {
                    result = EntityUtils.toString(httpEntity);
                }
            }

            closeableHttpResponse.close();
            // 关闭连接
            closeableHttpClient.close();

        } catch (IOException e) {
            logger.error(e.getMessage(), e);
            throw e;
        }

        return result;

    }