如果你是使用maven来管理项目,你需要在pom.xml添加如下配置:
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
<version>4.5</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpcore</artifactId>
<version>4.4.1</version>
</dependency>
示例代码如下:
package org.apache.http.examples.entity.mime; import java.io.IOException; import java.io.InterruptedIOException; import java.net.UnknownHostException; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Map.Entry; import javax.net.ssl.SSLException; import org.apache.commons.codec.Charsets; import org.apache.http.Header; import org.apache.http.HttpEntityEnclosingRequest; import org.apache.http.HttpRequest; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.HttpRequestRetryHandler; import org.apache.http.client.config.RequestConfig; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.client.protocol.HttpClientContext; import org.apache.http.client.utils.URIBuilder; import org.apache.http.config.SocketConfig; import org.apache.http.conn.ConnectTimeoutException; import org.apache.http.impl.client.HttpClients; import org.apache.http.impl.conn.PoolingHttpClientConnectionManager; import org.apache.http.protocol.HttpContext; import org.apache.http.util.EntityUtils; /** * 使用HttpClient发送和接收Http请求 * * @author manzhizhen * */ public class HttpUtils { private static HttpClient httpClient; // 最大连接数 private static final int MAX_CONNECTION = 100; // 每个route能使用的最大连接数,一般和MAX_CONNECTION取值一样 private static final int MAX_CONCURRENT_CONNECTIONS = 100; // 建立连接的超时时间,单位毫秒 private static final int CONNECTION_TIME_OUT = 200; // 请求超时时间,单位毫秒 private static final int REQUEST_TIME_OUT = 200; // 最大失败重试次数 private static final int MAX_FAIL_RETRY_COUNT = 3; // 请求配置,可以复用 private static RequestConfig requestConfig; static { SocketConfig socketConfig = SocketConfig.custom() .setSoTimeout(REQUEST_TIME_OUT).setSoKeepAlive(true) .setTcpNoDelay(true).build(); requestConfig = RequestConfig.custom() .setSocketTimeout(REQUEST_TIME_OUT) .setConnectTimeout(CONNECTION_TIME_OUT).build(); /** * 每个默认的 ClientConnectionPoolManager 实现将给每个route创建不超过2个并发连接,最多20个连接总数。 */ PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager(); connManager.setMaxTotal(MAX_CONNECTION); connManager.setDefaultMaxPerRoute(MAX_CONCURRENT_CONNECTIONS); connManager.setDefaultSocketConfig(socketConfig); httpClient = HttpClients.custom().setConnectionManager(connManager) // 添加重试处理器 .setRetryHandler(new MyHttpRequestRetryHandler()).build(); } public static void main(String[] args) { testGet(); } /** * 测试get方法 */ private static void testGet() { String url = "http://restapi.amap.com/v3/place/text"; Map<String, String> paramMap = new HashMap<String, String>(); paramMap.put("key", "95708f902ac2428ea119ec99fb70e6a3"); paramMap.put("keywords", "互联网金融大厦"); paramMap.put("city", "330100"); paramMap.put("extensions", "all"); try { System.out.println(get(url, paramMap)); } catch (Exception e) { e.printStackTrace(); } } /** * post请求 * * @param url * @param paramMap * @param headers * @return * @throws Exception */ public static String post(String url, Map<String, String> paramMap, List<Header> headers) throws Exception { URIBuilder uriBuilder = new URIBuilder(url); if (paramMap != null) { // 添加请求参数 for (Entry<String, String> entry : paramMap.entrySet()) { uriBuilder.addParameter(entry.getKey(), entry.getValue()); } } HttpPost httpPost = new HttpPost(uriBuilder.build()); if (headers != null) { // 添加请求首部 for (Header header : headers) { httpPost.addHeader(header); } } httpPost.setConfig(requestConfig); // 执行请求 HttpResponse response = httpClient.execute(httpPost); return EntityUtils.toString(response.getEntity(), Charsets.UTF_8); } /** * post请求,不带请求首部 * * @param url * @param paramMap * @return * @throws Exception */ public static String post(String url, Map<String, String> paramMap) throws Exception { return post(url, paramMap, null); } /** * get请求 * * @param url * @param paramMap * @param headers * @return * @throws Exception */ public static String get(String url, Map<String, String> paramMap, List<Header> headers) throws Exception { URIBuilder uriBuilder = new URIBuilder(url); if (paramMap != null) { // 添加请求参数 for (Entry<String, String> entry : paramMap.entrySet()) { uriBuilder.addParameter(entry.getKey(), entry.getValue()); } } HttpGet httpGet = new HttpGet(uriBuilder.build()); if (headers != null) { // 添加请求首部 for (Header header : headers) { httpGet.addHeader(header); } } httpGet.setConfig(requestConfig); // 执行请求 HttpResponse response = httpClient.execute(httpGet); return EntityUtils.toString(response.getEntity(), Charsets.UTF_8); } /** * get请求,不带请求首部 * * @param url * @param paramMap * @return * @throws Exception */ public static String get(String url, Map<String, String> paramMap) throws Exception { return get(url, paramMap, null); } /** * 请求重试处理器 * @author manzhizhen * */ private static class MyHttpRequestRetryHandler implements HttpRequestRetryHandler { @Override public boolean retryRequest(IOException exception, int executionCount, HttpContext context) { if (executionCount >= MAX_FAIL_RETRY_COUNT) { return false; } if (exception instanceof InterruptedIOException) { // 超时 return false; } if (exception instanceof UnknownHostException) { // 未知主机 return false; } if (exception instanceof ConnectTimeoutException) { // 连接被拒绝 return false; } if (exception instanceof SSLException) { // SSL handshake exception return false; } HttpClientContext clientContext = HttpClientContext.adapt(context); HttpRequest request = clientContext.getRequest(); boolean idempotent = !(request instanceof HttpEntityEnclosingRequest); if (idempotent) { // 如果请求被认为是幂等的,则重试 return true; } return false; } } }