### Java中实现类似于Python `requests.get`的功能 在Java中，可以使用多种方式来发送带有URL参数、头部信息的GET请求。以下是基于标准库以及第三方库（如Apache HttpClient或OkHttp）的方法。 #### 使用标准库 (`HttpURLConnection`) 这是最基础的方式之一，通过Java的标准类库完成HTTP GET请求： ```java import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; import java.util.HashMap; import java.util.Map; public class HttpGetExample { public static void main(String[] args) throws Exception { String urlString = "http://example.com/api"; Map<String, Object> params = new HashMap<>(); params.put("param1", "value1"); params.put("param2", "value2"); StringBuilder query = new StringBuilder(); for (Map.Entry<String, Object> entry : params.entrySet()) { if (query.length() > 0) { query.append("&"); } query.append(entry.getKey()).append("=").append(entry.getValue()); } URL url = new URL(urlString + "?" + query.toString()); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); // 设置请求方法为GET connection.setRequestMethod("GET"); // 添加自定义头信息 connection.addRequestProperty("Custom-Header", "HeaderValue"); int responseCode = connection.getResponseCode(); System.out.println("Response Code: " + responseCode); BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream())); String inputLine; StringBuffer content = new StringBuffer(); while ((inputLine = in.readLine()) != null) { content.append(inputLine); } in.close(); System.out.println(content.toString()); } } ``` 上述代码展示了如何构建带参数的GET请求并设置自定义头部信息[^5]。 --- #### 使用Apache HttpClient 如果希望简化操作流程，可以选择引入Apache HttpClient库。这是一个功能强大的工具包，支持更复杂的HTTP交互需求。 Maven依赖配置如下： ```xml <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.13</version> </dependency> ``` 下面是具体实现示例： ```java import org.apache.http.client.methods.CloseableHttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.util.EntityUtils; import java.util.ArrayList; import java.util.List; public class ApacheHttpGetExample { public static void main(String[] args) throws Exception { CloseableHttpClient httpClient = HttpClients.createDefault(); List<String> queryParams = new ArrayList<>(); queryParams.add("param1=value1"); queryParams.add("param2=value2"); String queryString = String.join("&", queryParams); String url = "http://example.com/api?" + queryString; HttpGet request = new HttpGet(url); // 设置头部信息 request.setHeader("Custom-Header", "HeaderValue"); try (CloseableHttpResponse response = httpClient.execute(request)) { String responseBody = EntityUtils.toString(response.getEntity()); System.out.println("Response Body: " + responseBody); System.out.println("Status Code: " + response.getStatusLine().getStatusCode()); } } } ``` 此代码片段利用了Apache HttpClient创建了一个GET请求，并设置了查询字符串和自定义头部信息[^6]。 --- #### 使用OkHttp 对于现代开发环境而言，OkHttp是一个轻量级且高效的HTTP客户端选项。它提供了简洁易读的API设计。 Gradle依赖配置如下： ```gradle implementation 'com.squareup.okhttp3:okhttp:4.9.3' ``` 下面是一段完整的代码实例： ```java import okhttp3.OkHttpClient; import okhttp3.Request; import okhttp3.Response; import java.io.IOException; import java.util.concurrent.TimeUnit; public class OkHttpGetExample { private final OkHttpClient client = new OkHttpClient.Builder() .connectTimeout(10, TimeUnit.SECONDS) .build(); public void run() throws IOException { String url = "http://example.com/api?param1=value1&param2=value2"; Request request = new Request.Builder() .url(url) .addHeader("Custom-Header", "HeaderValue") // 自定义头部字段 .get() .build(); try (Response response = client.newCall(request).execute()) { if (!response.isSuccessful()) throw new IOException("Unexpected code " + response); System.out.println(response.body().string()); // 输出响应体内容 } } public static void main(String[] args) throws IOException { new OkHttpGetExample().run(); } } ``` 这段代码演示了如何借助OkHttp发起一个包含查询参数与头部数据的GET请求[^7]。 --- ### 总结说明 无论是采用原生库还是外部框架，在实