httpclient向HTTPS发送数据建立SSL连接时的异常
异常信息如下：
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
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原因：服务器的证书不被信任。一般是这样造成的。
使用KEYTOOL工具创建证书，然后用TOMCAT启动后，在浏览器打开网站时，会出现证书不被信任的提示。当然，利用HTTPCLIENT向服务端HTTPS发送数据时，HTTPCLIENT也会检测服务端的证书是否被信任，不被信任就抛出上面的异常。
解决办法有两种，一种是使证书被客户端信任。另一种是使用HTTPCLIENT发送数据时不检测服务器证书是否可信。
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第一种办法，使证书被信任。
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找正规CA签发证书，或者自己签发证书（只能那一台客户机上可信）。找正规CA签发证书就不说了，自己签发证书呢，见我的其他文章。
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我发现，自己签名的证书弄好之后，从客户端打开服务端地址时，不再提示上面的错误，但是还是不能发送数据。原因是什么呢？因为那台证书在客户端操作系统上可信，但是在JAVA的KEYSTORE里不可信，要把服务端的证书导入KEYSTORE库中
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导入办法：
打开命令行窗口，并到<java-home>\lib\security\目录下，运行下面的命令：
import java.io.IOException; import java.net.InetAddress; import java.net.InetSocketAddress; import java.net.Socket; import java.net.SocketAddress; import java.net.UnknownHostException; import java.security.KeyManagementException; import java.security.NoSuchAlgorithmException; import java.security.cert.CertificateException; import java.security.cert.X509Certificate; import javax.net.SocketFactory; import javax.net.ssl.SSLContext; import javax.net.ssl.TrustManager; import javax.net.ssl.X509TrustManager; import org.apache.commons.httpclient.ConnectTimeoutException; import org.apache.commons.httpclient.params.HttpConnectionParams; import org.apache.commons.httpclient.protocol.SecureProtocolSocketFactory; public class MySecureProtocolSocketFactory implements SecureProtocolSocketFactory { private SSLContext sslcontext = null; private SSLContext createSSLContext() { SSLContext sslcontext=null; try { sslcontext = SSLContext.getInstance("SSL"); sslcontext.init(null, new TrustManager[]{new TrustAnyTrustManager()}, new java.security.SecureRandom()); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (KeyManagementException e) { e.printStackTrace(); } return sslcontext; } private SSLContext getSSLContext() { if (this.sslcontext == null) { this.sslcontext = createSSLContext(); } return this.sslcontext; } public Socket createSocket(Socket socket, String host, int port, boolean autoClose) throws IOException, UnknownHostException { return getSSLContext().getSocketFactory().createSocket( socket, host, port, autoClose ); } public Socket createSocket(String host, int port) throws IOException, UnknownHostException { return getSSLContext().getSocketFactory().createSocket( host, port ); } public Socket createSocket(String host, int port, InetAddress clientHost, int clientPort) throws IOException, UnknownHostException { return getSSLContext().getSocketFactory().createSocket(host, port, clientHost, clientPort); } public Socket createSocket(String host, int port, InetAddress localAddress, int localPort, HttpConnectionParams params) throws IOException, UnknownHostException, ConnectTimeoutException { if (params == null) { throw new IllegalArgumentException("Parameters may not be null"); } int timeout = params.getConnectionTimeout(); SocketFactory socketfactory = getSSLContext().getSocketFactory(); if (timeout == 0) { return socketfactory.createSocket(host, port, localAddress, localPort); } else { Socket socket = socketfactory.createSocket(); SocketAddress localaddr = new InetSocketAddress(localAddress, localPort); SocketAddress remoteaddr = new InetSocketAddress(host, port); socket.bind(localaddr); socket.connect(remoteaddr, timeout); return socket; } } //自定义私有类 private static class TrustAnyTrustManager implements X509TrustManager { public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException { } public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException { } public X509Certificate[] getAcceptedIssuers() { return new X509Certificate[]{}; } } } ?