使用HttpClient实现get/post请求

pom.xml

<!-- httpclient dependency -->
<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpclient</artifactId>
  <version>4.5.3</version>
</dependency>

自定义HttpUitl工具类

public class HttpUtil {
    
    /**
     * 通过get请求获取响应报文
     * @param uri 请求路径 
     * @param paramMap 请求参数
     * @return 字符串格式的响应报文
     * @throws ClientProtocolException HttpClient定义的客户端协议异常
     * @throws IOException  读写异常
     * @throws URISyntaxException URI格式异常
     */
    public static String getGet(String uri , Map<String, Object> paramMap) throws ClientProtocolException, IOException, URISyntaxException {
        CloseableHttpClient client = HttpClients.createDefault();
        URIBuilder uriBuilder = new URIBuilder(uri);
        if(paramMap != null) {
            //遍历参数集合并添加到uriBuilder当中
            for (String key : paramMap.keySet()) {
                uriBuilder.setParameter(key, String.valueOf(paramMap.get(key)));
            }
        }
        HttpGet httpGet = new HttpGet(uriBuilder.build());
        //请求uri
        CloseableHttpResponse response = client.execute(httpGet);
        //获取响应的状态码，200为响应成功
        int statusCode = response.getStatusLine().getStatusCode();
        String responseStr = null;
        if(statusCode == 200) {
            //获取响应实体对象
            HttpEntity entity = response.getEntity();
            //通过EntityUtil工具类转换响应报文
            responseStr = EntityUtils.toString(entity,"UTF-8");
        }else {
            responseStr = "NO RESPONSE BODY!";
        }
        response.close();
        client.close();
        return responseStr;
    }
    
    /**
     * 通过post请求获取响应报文
     * @param uri 请求路径
     * @param paramMap  请求参数
     * @return  字符串格式的响应报文
     * @throws Exception 异常
     */
    public static String getPost(String uri , Map<String, Object> paramMap) throws Exception {
        CloseableHttpClient client = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(uri);
        //创建参数对象集合
        List<NameValuePair> paramList = new ArrayList<NameValuePair>();
        if(paramMap != null) {
            //遍历并添加请求参数到集合中
            for(String key : paramMap.keySet()) {
                paramList.add(new BasicNameValuePair(key, String.valueOf(paramMap.get(key))));
            }
        }
        //创建Entity对象
        StringEntity stringEntity = new UrlEncodedFormEntity(paramList , "UTF-8");
        //为post请求添加entity对象
        httpPost.setEntity(stringEntity);
        //请求uri
        CloseableHttpResponse response = client.execute(httpPost);
        //获取响应的状态吗，200为响应成功
        int statusCode = response.getStatusLine().getStatusCode();
        String responseStr = null;
        if(statusCode == 200) {
            //获取响应实体对象
            HttpEntity entity = response.getEntity();
            //通过EntityUtil工具类转换响应报文
            responseStr = EntityUtils.toString(entity , "UTF-8");
        } else {
            responseStr = "NO RESPONSE BODY!";
        }
        response.close();
        client.close();
        return responseStr;
    }
}

单元测试

    @Test
    public void two() throws ClientProtocolException, IOException, URISyntaxException {
        Map<String, Object> paramMap = new HashMap<>();
        paramMap.put("wd", "json");
        String resultStr = HttpUtil.getGet("http://www.baidu.com/s", paramMap);
        System.out.println(resultStr);
    }
    
    @Test
    public void three() throws Exception {
        Map<String, Object> paramMap = new HashMap<>();
        paramMap.put("username", "张三");
        paramMap.put("password", "这是一个经过MD5加密的密码");
        String resultStr = HttpUtil.getPost("http://127.0.0.1:8080/springmvcTemplate/One/two.json", paramMap);
        System.out.println(resultStr);
    }