Java 实现HTTP请求的方式总结

╰+哭是因爲堅強的太久メ 2024-05-05 22:07 55阅读 0赞

### **1.**HttpURLConnection java原生 ###

Java中用于进行HTTP通信的类，它预先定义了一些方法，如 setRequestMethod()、setRequestProperty() 和 getResponseCode()，方便开发者自由地控制请求和响应

import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.net.URLEncoder;
    import java.nio.charset.StandardCharsets;
    
    public class HttpURLConnectionExample {
        public static void main(String[] args) {
            try {
                // 创建URL对象，附加参数到查询字符串中  GET
                String urlString = "https://api.example.com/data?param1=" + URLEncoder.encode("value1", StandardCharsets.UTF_8)
                        + "&param2=" + URLEncoder.encode("value2", StandardCharsets.UTF_8);
                URL url = new URL(urlString);
                // 打开连接
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
      /** 设置通用的请求属性
                connection.setRequestProperty("accept", "*/*");
                connection.setRequestProperty("connection", "Keep-Alive");
                connection.setRequestProperty("Content-Type","application/json;charset=utf-8");
                connection.setRequestProperty("user-agent",
                	"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
    
    **/
                // 设置请求方法为GET
                connection.setRequestMethod("GET");
                // 发送请求并获取响应码...
                int responseCode = connection.getResponseCode();
                // 判断响应码
                if (responseCode == HttpURLConnection.HTTP_OK) {
                    // 读取响应内容
                    BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                    String line;
                    StringBuilder response = new StringBuilder();
                    while ((line = reader.readLine()) != null) {
                        response.append(line);
                    }
                    reader.close();
    
                    // 处理响应内容
                    System.out.println(response.toString());
                } else {
                    // 处理错误情况
                    System.out.println("Request failed. Response code: " + responseCode);
                }
    
                // 关闭连接
                connection.disconnect();
            } catch (IOException e) {
                e.printStackTrace();
            }
    
    //==================================================================================
                // 创建URL对象  POST
                URL postUrl = new URL("https://api.example.com/post");
                HttpURLConnection postConnection = (HttpURLConnection) postUrl.openConnection();
    
                // 设置请求方法为POST
                postConnection.setRequestMethod("POST");
    
                // 启用输出流，将参数写入请求体
                postConnection.setDoOutput(true);
    
                // 拼接参数字符串
                String postData = "param1=" + URLEncoder.encode("value1", StandardCharsets.UTF_8)
                        + "&param2=" + URLEncoder.encode("value2", StandardCharsets.UTF_8);
    
                // 将参数字符串写入请求体
                postConnection.getOutputStream().write(postData.getBytes(StandardCharsets.UTF_8));
    
                // 发送请求并获取响应码...
    
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

### 2.从Java 11开始，推荐使用`java.net.http.HttpClient`类来进行HTTP通信 ###

import java.io.IOException;
    import java.net.URI;
    import java.net.URLEncoder;
    import java.net.http.HttpClient;
    import java.net.http.HttpHeaders;
    import java.net.http.HttpRequest;
    import java.net.http.HttpResponse;
    import java.nio.charset.StandardCharsets;
    
    public class HttpClientExample {
        public static void main(String[] args) {
            try {
                // 创建HttpClient对象
                HttpClient httpClient = HttpClient.newBuilder().build();
    
                // 创建GET请求，并添加参数到查询字符串中
                String urlString = "https://api.example.com/data?param1=" + URLEncoder.encode("value1", StandardCharsets.UTF_8)
                        + "&param2=" + URLEncoder.encode("value2", StandardCharsets.UTF_8);
                HttpRequest getRequest = HttpRequest.newBuilder()
                        .GET()
                        .uri(URI.create(urlString))
                        .build();
    
                // 发送GET请求并获取响应
                HttpResponse<String> getResponse = httpClient.send(getRequest, HttpResponse.BodyHandlers.ofString());
    
                // 处理GET响应...
                System.out.println(getResponse.body());
    
                // 创建POST请求，并设置请求体
                String postData = "param1=" + URLEncoder.encode("value1", StandardCharsets.UTF_8)
                        + "&param2=" + URLEncoder.encode("value2", StandardCharsets.UTF_8);
                HttpRequest postRequest = HttpRequest.newBuilder()
                        .POST(HttpRequest.BodyPublishers.ofString(postData))
                        .uri(URI.create("https://api.example.com/post"))
                        .header("Content-Type", "application/x-www-form-urlencoded")
                        .build();
    
                // 发送POST请求并获取响应
                HttpResponse<String> postResponse = httpClient.send(postRequest, HttpResponse.BodyHandlers.ofString());
    
                // 处理POST响应...
                System.out.println(postResponse.body());
            } catch (IOException | InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

### 3.HttpClient commons-httpclient包 ###

import com.alibaba.fastjson.JSON;
    import org.apache.commons.httpclient.HttpClient;
    import org.apache.commons.httpclient.methods.PostMethod;
     
    import java.io.IOException;
    import java.util.HashMap;
    import java.util.Map;
     
    public class HttpTest2 {
     
        public static void main(String[] args) {
            HttpClient httpClient = new HttpClient();
            PostMethod postMethod = new PostMethod("http://127.0.0.1/xxx");
     
            postMethod.addRequestHeader("accept", "*/*");
            //设置Content-Type，此处根据实际情况确定
            postMethod.addRequestHeader("Content-Type", "application/x-www-form-urlencoded");
            //必须设置下面这个Header
            //添加请求参数
            Map paraMap = new HashMap();
            paraMap.put("type", "wx");
            paraMap.put("mchid", "10101");
            postMethod.addParameter("consumerAppId", "test");
            postMethod.addParameter("serviceName", "queryMerchantService");
            postMethod.addParameter("params", JSON.toJSONString(paraMap));
            String result = "";
            try {
                int code = httpClient.executeMethod(postMethod);
                if (code == 200){
                    result = postMethod.getResponseBodyAsString();
                    System.out.println("result:" + result);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

### 4.Apache HttpClient 中 CloseableHttpClient ###

import org.apache.http.HttpEntity;
    import org.apache.http.HttpResponse;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    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.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.util.EntityUtils;
    
    import java.io.IOException;
    import java.net.URI;
    import java.net.URISyntaxException;
    import java.nio.charset.StandardCharsets;
    import java.util.ArrayList;
    import java.util.List;
    
    public class ApacheHttpClientExample {
        public static void main(String[] args) {
            try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
                // 创建GET请求，并添加参数到查询字符串中
                URIBuilder uriBuilder = new URIBuilder("https://api.example.com/data");
                uriBuilder.addParameter("param1", "value1");
                uriBuilder.addParameter("param2", "value2");
                HttpGet httpGet = new HttpGet(uriBuilder.build());
    
                // 发送GET请求并获取响应
                HttpResponse getResponse = httpClient.execute(httpGet);
                HttpEntity getEntity = getResponse.getEntity();
                String getResponseBody = EntityUtils.toString(getEntity, StandardCharsets.UTF_8);
    
                // 处理GET响应...
                System.out.println(getResponseBody);
    
                // 创建POST请求，并设置请求体
                HttpPost httpPost = new HttpPost("https://api.example.com/post");
                List<NameValuePair> params = new ArrayList<>();
                params.add(new BasicNameValuePair("param1", "value1"));
                params.add(new BasicNameValuePair("param2", "value2"));
                httpPost.setEntity(new UrlEncodedFormEntity(params, StandardCharsets.UTF_8));
    
                // 发送POST请求并获取响应
                HttpResponse postResponse = httpClient.execute(httpPost);
                HttpEntity postEntity = postResponse.getEntity();
                String postResponseBody = EntityUtils.toString(postEntity, StandardCharsets.UTF_8);
    
                // 处理POST响应...
                System.out.println(postResponseBody);
            } catch (IOException | URISyntaxException e) {
                e.printStackTrace();
            }
        }
    }

### 5.RestTemplate ###

@Autowired
     private RestTemplate restTemplate;
     1.
    UrlQuery query = new UrlQuery();
     query.add("_w_third_source", "edit");
     query.add("XXX", name == null ? "test" : URLEncoder.encode(name, StandardCharsets.UTF_8));
    
    String url = String.format("/api/xx/v1/xx/%s/link?type=%s&%s", param1, param2, query.build(StandardCharsets.UTF_8));
    //query.build — 构建URL查询字符串，即将key-value键值对转换为key1=v1&key2=&key3=v3形式
    //签名、请求头
      HttpHeaders headers = new HttpHeaders();
      headers.set("Authorization", authorization);
      headers.set("Content-Type", "application/json");
      headers.set("docs-Date", dateString);
      HttpEntity<?> httpEntity = new HttpEntity<>(headers);
    ResponseEntity<XXXResponse> rse=restTemplate.exchange(host + url, HttpMethod.GET, httpEntity, XXXResponse.class).getBody();
    if(rse.getStatusCodeValue==200){
    //代码  
    }
    
    //请求体时 DigestUtils.sha256Hex(content);
    
    2.      //getForObject方法的第二个参数是响应结果的类型
      String url = String.format("https://qyapi.weixin.qq.com/cgi-bin/gettoken? 
      corpid=%s&corpsecret=%s", cropId, secret);
      Map<String, Object> resp = restTemplate.getForObject(url, Map.class);
    // Map<String, Object> resp = httpUtil.get(url, Map.class).getBody();
       String accessToken = (String) resp.get("access_token");
       Integer expiresIn = (Integer) resp.get("expires_in");
    3. //与2区别  2直接返回响应结果  3 响应结果存储在ResponseEntity对象中
    final ResponseEntity<TokenRSP> res = restTemplate.getForEntity(String.format("https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=%s&secret=%s", APPID, SECRET), TokenRSP.class);
            final String nowToken = res.getBody().getAccess_token();
            final long expiresTime = res.getBody().getExpires_in();