Java利用Apache HttpClient调用HTTP接口并传递参数（含GET、POST、JSON示例）

在Java中使用HttpClient来调用HTTP接口（类似于cURL命令）并传递参数，可以按照以下步骤进行。我们将使用Apache HttpClient库来实现这一点。 首先，确保你已经添加了Apache HttpClient的依赖。如果你使用的是Maven，可以在`pom.xml`文件中添加以下依赖： ```xml <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.13</version> </dependency> ``` 接下来，我们编写一个示例代码来调用一个HTTP接口并传递参数。 示例：GET请求 假设我们要调用一个GET请求，并传递查询参数。 ```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.client.utils.URIBuilder; import org.apache.http.util.EntityUtils; import java.net.URI; import java.io.IOException; public class HttpClientExample { public static void main(String[] args) { try { // 创建HttpClient对象 CloseableHttpClient httpClient = HttpClients.createDefault(); // 构建URI URIBuilder uriBuilder = new URIBuilder("http://example.com/api"); uriBuilder.setParameter("param1", "value1"); uriBuilder.setParameter("param2", "value2"); URI uri = uriBuilder.build(); // 创建HttpGet请求 HttpGet httpGet = new HttpGet(uri); // 执行请求 CloseableHttpResponse response = httpClient.execute(httpGet); try { // 获取响应状态码 int statusCode = response.getStatusLine().getStatusCode(); System.out.println("Status Code: " + statusCode); // 获取响应内容 String responseContent = EntityUtils.toString(response.getEntity()); System.out.println("Response Content: " + responseContent); } finally { // 关闭响应 response.close(); } // 关闭HttpClient httpClient.close(); } catch (Exception e) { e.printStackTrace(); } } } ``` 示例：POST请求 假设我们要调用一个POST请求，并传递表单参数。 ```java 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.HttpClients; import org.apache.http.util.EntityUtils; import java.io.IOException; public class HttpClientExample { public static void main(String[] args) { try { // 创建HttpClient对象 CloseableHttpClient httpClient = HttpClients.createDefault(); // 创建HttpPost请求 HttpPost httpPost = new HttpPost("http://example.com/api"); // 设置请求头 httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded"); // 设置请求体 StringEntity params = new StringEntity("param1=value1&param2=value2"); httpPost.setEntity(params); // 执行请求 CloseableHttpResponse response = httpClient.execute(httpPost); try { // 获取响应状态码 int statusCode = response.getStatusLine().getStatusCode(); System.out.println("Status Code: " + statusCode); // 获取响应内容 String responseContent = EntityUtils.toString(response.getEntity()); System.out.println("Response Content: " + responseContent); } finally { // 关闭响应 response.close(); } // 关闭HttpClient httpClient.close(); } catch (Exception e) { e.printStackTrace(); } } } ``` 示例：JSON请求 假设我们要调用一个POST请求，并传递JSON格式的参数。 ```java 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.HttpClients; import org.apache.http.util.EntityUtils; import java.io.IOException; public class HttpClientExample { public static void main(String[] args) { try { // 创建HttpClient对象 CloseableHttpClient httpClient = HttpClients.createDefault(); // 创建HttpPost请求 HttpPost httpPost = new HttpPost("http://example.com/api"); // 设置请求头 httpPost.setHeader("Content-Type", "application/json"); // 设置请求体 String json = "{\"param1\": \"value1\", \"param2\": \"value2\"}"; StringEntity entity = new StringEntity(json); httpPost.setEntity(entity); // 执行请求 CloseableHttpResponse response = httpClient.execute(httpPost); try { // 获取响应状态码 int statusCode = response.getStatusLine().getStatusCode(); System.out.println("Status Code: " + statusCode); // 获取响应内容 String responseContent = EntityUtils.toString(response.getEntity()); System.out.println("Response Content: " + responseContent); } finally { // 关闭响应 response.close(); } // 关闭HttpClient httpClient.close(); } catch (Exception e) { e.printStackTrace(); } } } ``` 以上示例展示了如何使用Apache HttpClient库在Java中调用HTTP接口并传递不同类型的参数。你可以根据实际需求选择合适的请求方法和参数类型。 ######[AI写代码神器 | 1123点数解答 | 2024-11-13 17:29:38]