HttpClient

ゞ浴缸里的玫瑰 2022-05-21 04:43 172阅读 0赞

# Get请求 #

@Test
    public void testHttpGet() throws Exception {
        // 第一步：把HttpClient使用的jar包添加到工程中。
        // 第二步：创建一个HttpClient的测试类
        // 第三步：创建测试方法。
        // 第四步：创建一个HttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 第五步：创建一个HttpGet对象，需要指定一个请求的url
        HttpGet get = new HttpGet("http://www.baidu.com");
        // 第六步：执行请求。
        CloseableHttpResponse response = httpClient.execute(get);
        // 第七步：接收返回结果。HttpEntity对象。
        HttpEntity entity = response.getEntity();
        // 第八步：取响应的内容。
        String html = EntityUtils.toString(entity);
        System.out.println(html);
        // 第九步：关闭response、HttpClient。
        response.close();
        httpClient.close();
    }

# Post请求 #

@Test
    public void testHttpPost() throws Exception {
        // 第一步：创建一个httpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 第二步：创建一个HttpPost对象。需要指定一个url
        HttpPost post = new HttpPost("http://localhost:8080/posttest.do");
        // 第三步：创建一个list模拟表单，list中每个元素是一个NameValuePair对象
        List<NameValuePair> formList = new ArrayList<>();
        formList.add(new BasicNameValuePair("name", "张三"));
        formList.add(new BasicNameValuePair("pass", "1243"));
        // 第四步：需要把表单包装到Entity对象中。StringEntity
        StringEntity entity = new UrlEncodedFormEntity(formList, "utf-8");
        post.setEntity(entity);
        // 第五步：执行请求。
        CloseableHttpResponse response = httpClient.execute(post);
        // 第六步：接收返回结果
        HttpEntity httpEntity = response.getEntity();
        String result = EntityUtils.toString(httpEntity);
        System.out.println(result);
        // 第七步：关闭流。
        response.close();
        httpClient.close();
    }

# HttpClientUtil #

import java.io.IOException;
    import java.net.URI;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    
    import org.apache.http.NameValuePair;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.client.utils.URIBuilder;
    import org.apache.http.entity.ContentType;
    import org.apache.http.entity.StringEntity;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.util.EntityUtils;
    
    public class HttpClientUtil { 
    
        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();
    
                // 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);
        }
    
        public static String doPost(String url, Map<String, String> param) {
            // 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);
                    httpPost.setEntity(entity);
                }
                // 执行http请求
                response = httpClient.execute(httpPost);
                resultString = EntityUtils.toString(response.getEntity(), "utf-8");
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    response.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            return resultString;
        }
    
        public static String doPost(String url) {
            return doPost(url, null);
        }
    
        public static String doPostJson(String url, String json) {
            // 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);
                httpPost.setEntity(entity);
                // 执行http请求
                response = httpClient.execute(httpPost);
                resultString = EntityUtils.toString(response.getEntity(), "utf-8");
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    response.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            return resultString;
        }
    }