在java中,特别是java web中,我们经常需要碰到的一个场景是我们需要从服务端去发送http请求,获取到数据,而不是直接从浏览器输入请求网址获得相应。比如我们想访问微信接口,获取其返回信息。
在这里需要用到java的HttpURLConnection类,此类可以模拟http请求,获取到的响应以输入流的形式被程序所取到。现将相关方法整理为工具类。
package com.m_gecko.util; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.io.UnsupportedEncodingException; import java.net.ConnectException; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.net.URLEncoder; import java.util.List; import java.util.Map; import javax.net.ssl.HttpsURLConnection; import javax.net.ssl.SSLContext; import javax.net.ssl.SSLSocketFactory; import javax.net.ssl.TrustManager; import org.apache.commons.io.IOUtils; public class HttpUtil { /** * 模拟http的get请求,获取响应(输入流),然后把输入流转为 * * @param url * @return */ public static String httpGet(String url) { HttpURLConnection connection = null; InputStream response = null; try { connection = (HttpURLConnection) new URL(url).openConnection(); connection.setConnectTimeout(10000); connection.setReadTimeout(10000); response = connection.getInputStream(); if (response != null) { String nextLine = IOUtils.toString(response, "utf-8"); return nextLine; } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (response != null) try { response.close(); } catch (IOException e) { e.printStackTrace(); } if (connection != null) { connection.disconnect(); connection = null; } } return null; } /** * 模拟http的post请求,类似上面 * * @param url * @return */ public static String httpPost(String url) { HttpURLConnection connection = null; InputStream response = null; try { connection = (HttpURLConnection) new URL(url).openConnection(); connection.setConnectTimeout(30000); connection.setReadTimeout(30000); // 发送POST请求必须设置如下两行 connection.setDoOutput(true); connection.setDoInput(true); response = connection.getInputStream(); if (response != null) { String nextLine = IOUtils.toString(response, "utf-8"); return nextLine; } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (response != null) try { response.close(); } catch (IOException e) { e.printStackTrace(); } if (connection != null) { connection.disconnect(); connection = null; } } return null; } /** * 向指定URL发送GET方法的请求 * * @param url * 发送请求的URL * @param param * 请求参数,请求参数应该是 name1=value1&name2=value2 的形式。 * @return URL 所代表远程资源的响应结果 */ public static String sendGet(String url, String param) { String result = ""; BufferedReader in = null; try { String urlNameString = url + "?" + param; URL realUrl = new URL(urlNameString); // 打开和URL之间的连接 HttpURLConnection connection = (HttpURLConnection) realUrl .openConnection(); // 设置通用的请求属性 connection.setRequestProperty("accept", "*/*"); connection.setRequestProperty("connection", "Keep-Alive"); connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)"); // 建立实际的连接 connection.connect(); // 获取所有响应头字段 Map<String, List<String>> map = connection.getHeaderFields(); // 遍历所有的响应头字段 // for (String key : map.keySet()) { // System.out.println(key + "--->" + map.get(key)); // } // 定义 BufferedReader输入流来读取URL的响应 in = new BufferedReader(new InputStreamReader( connection.getInputStream(), "utf-8")); String line; while ((line = in.readLine()) != null) { result += line; } } catch (Exception e) { System.out.println("发送GET请求出现异常!" + e); e.printStackTrace(); } // 使用finally块来关闭输入流 finally { try { if (in != null) { in.close(); } } catch (Exception e2) { e2.printStackTrace(); } } return result; } /** * 向指定 URL 发送POST方法的请求 * * @param url * 发送请求的 URL * @param param * 请求参数,请求参数应该是 name1=value1&name2=value2 的形式。 * @return 所代表远程资源的响应结果 */ public static String sendPost(String url, String param) { PrintWriter out = null; BufferedReader in = null; String result = ""; try { URL realUrl = new URL(url); // 打开和URL之间的连接 HttpURLConnection conn = (HttpURLConnection) realUrl .openConnection(); // 设置通用的请求属性 conn.setRequestProperty("accept", "*/*"); conn.setRequestProperty("connection", "Keep-Alive"); conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)"); // 发送POST请求必须设置如下两行 conn.setDoOutput(true); conn.setDoInput(true); // 获取URLConnection对象对应的输出流 // out = new PrintWriter(conn.getOutputStream()); // // 发送请求参数 // out.print(param); // // flush输出流的缓冲 // out.flush(); // 定义BufferedReader输入流来读取URL的响应 in = new BufferedReader(new InputStreamReader( conn.getInputStream(), "utf-8")); String line; while ((line = in.readLine()) != null) { result += line; } } catch (Exception e) { System.out.println("发送 POST 请求出现异常!" + e); e.printStackTrace(); } // 使用finally块来关闭输出流、输入流 finally { try { if (out != null) { out.close(); } if (in != null) { in.close(); } } catch (IOException ex) { ex.printStackTrace(); } } return result; } /** * 向指定 URL 发送POST方法的请求 * * @param url * 发送请求的 URL * @param params * 请求的参数集合 * @return 远程资源的响应结果 */ public static String sendPost(String url, Map<String, String> params) { OutputStreamWriter out = null; BufferedReader in = null; StringBuilder result = new StringBuilder(); try { URL realUrl = new URL(url); HttpURLConnection conn = (HttpURLConnection) realUrl .openConnection(); // 发送POST请求必须设置如下两行 conn.setDoOutput(true); conn.setDoInput(true); // POST方法 conn.setRequestMethod("POST"); // 设置通用的请求属性 conn.setRequestProperty("accept", "*/*"); conn.setRequestProperty("connection", "Keep-Alive"); conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)"); conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); conn.connect(); // 获取URLConnection对象对应的输出流 out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8"); // 发送请求参数 if (params != null) { StringBuilder param = new StringBuilder(); for (Map.Entry<String, String> entry : params.entrySet()) { if (param.length() > 0) { param.append("&"); } param.append(entry.getKey()); param.append("="); param.append(entry.getValue()); // System.out.println(entry.getKey()+":"+entry.getValue()); } System.out.println("param:" + param.toString()); out.write(param.toString()); } // flush输出流的缓冲 out.flush(); // 定义BufferedReader输入流来读取URL的响应 in = new BufferedReader(new InputStreamReader( conn.getInputStream(), "UTF-8")); String line; while ((line = in.readLine()) != null) { result.append(line); } } catch (Exception e) { e.printStackTrace(); } // 使用finally块来关闭输出流、输入流 finally { try { if (out != null) { out.close(); } if (in != null) { in.close(); } } catch (IOException ex) { ex.printStackTrace(); } } return result.toString(); } /** * url编码 * * @param str * @param charset * @return * @throws UnsupportedEncodingException */ public static String urlEncoder(String str, String charset) throws UnsupportedEncodingException { if (str == null) { str = ""; } String result = URLEncoder.encode(str, charset); return result; } /** * 发送https请求 * * @param requestUrl * 请求地址 * @param requestMethod * 请求方式(GET、POST) * @param outputStr * 提交的数据 * @return 返回微信服务器响应的信息 */ public static String httpsRequest(String requestUrl, String requestMethod, String outputStr) { try { // 创建SSLContext对象,并使用我们指定的信任管理器初始化 TrustManager[] tm = { new MyX509TrustManager() }; SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE"); sslContext.init(null, tm, new java.security.SecureRandom()); // 从上述SSLContext对象中得到SSLSocketFactory对象 SSLSocketFactory ssf = sslContext.getSocketFactory(); URL url = new URL(requestUrl); HttpsURLConnection conn = (HttpsURLConnection) url.openConnection(); conn.setSSLSocketFactory(ssf); conn.setDoOutput(true); conn.setDoInput(true); conn.setUseCaches(false); // 设置请求方式(GET/POST) conn.setRequestMethod(requestMethod); conn.setRequestProperty("content-type", "application/x-www-form-urlencoded"); // 当outputStr不为null时向输出流写数据 if (null != outputStr) { OutputStream outputStream = conn.getOutputStream(); // 注意编码格式 outputStream.write(outputStr.getBytes("UTF-8")); outputStream.close(); } // 从输入流读取返回内容 InputStream inputStream = conn.getInputStream(); InputStreamReader inputStreamReader = new InputStreamReader( inputStream, "utf-8"); BufferedReader bufferedReader = new BufferedReader( inputStreamReader); String str = null; StringBuffer buffer = new StringBuffer(); while ((str = bufferedReader.readLine()) != null) { buffer.append(str); } // 释放资源 bufferedReader.close(); inputStreamReader.close(); inputStream.close(); inputStream = null; conn.disconnect(); return buffer.toString(); } catch (ConnectException ce) { ce.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } return null; } }
其中https请求所需要的信任管理器实现了X509TrustManager接口。
package com.m_gecko.util; import java.security.cert.CertificateException; import java.security.cert.X509Certificate; import javax.net.ssl.X509TrustManager; /** * 信任管理器 * @author xdx */ public class MyX509TrustManager implements X509TrustManager { // 检查客户端证书 public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException { } // 检查服务器端证书 public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException { } // 返回受信任的X509证书数组 public X509Certificate[] getAcceptedIssuers() { return null; } }