Https请求不信任服务器的证书报错解决方案

调用第三方系统Https接口时，出现报错信息如下:
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
at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1946)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:316)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310)

原因：
查阅资料发现，从client和server端SSL握手过程看，问题发生在客户端校验证书。 根本原因是客户端不信任服务器的证书或者客户端封装ssl时缺少服务端的证书。

解决方法：
1、去服务端获取证书，修改代码加载该证书（服务器可能登录不了，无法获取证书）
2、通过代码获取服务端证书，将证书导入到jdk中

方式1：
可通过复制文末的代码获取服务端证书，使用方法：
//用cmd进入base窗口在代码所在路径编译
javac InstallCert.java;
//运行
java InstallCert XX.XX.XX.XXX:XXXX //服务端IP及SSL端口
在所在路径会生成一个jssecacerts文件，再复制jssecacerts文件放到$JAVA_HOME/jre/lib/security目录下，重启动你的Web Server，使证书生效；
如果使用方式1不行，执行方法2；

方式2：
在cmd窗口执行：
keytool -import -alias “repo.maven.apache.org-1” -file “c:\zjg.cer” -keystore “jdk路径\jre\lib\security\jssecacerts”

其中zjg.cer为从http://repo.maven.apache.org/下载的证书文件，注意的是alias的参数，应该不能随便起，从方法1中的InstallCert.java文件看，应该是“host-数字”的格式。比如“repo.maven.apache.org”的alias参数就应该是“repo.maven.apache.org-1”

此时会提示输入密码，密码使用jdk默认密码：changeit，或者在上面命令后增加-storepass changeit设置密码参数；然后按照提醒操作即可。最后会自动加载证书。如果依然不行，使用方式3；

方式3：
通过重写HostnameVerifier的verify方法可绕过主机校验。
//连接工具类中添加设置不验证主机代码
private static final HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
public boolean verify(String hostname, SSLSession session) {
return true;
}
};
连接时：
conn = (HttpsURLConnection) uUrl.openConnection();
conn.setHostnameVerifier(DO_NOT_VERIFY);

InstallCert.java工具类如下：

import java.io.*;
import java.net.URL;
  
import java.security.*;
import java.security.cert.*;
  
import javax.net.ssl.*;
  
public class InstallCert {
  
public static void main(String[] args) throws Exception {
String host;
int port;
char[] passphrase;
if ((args.length == 1) || (args.length == 2)) {
String[] c = args[0].split(":");
host = c[0];
port = (c.length == 1) ? 443 : Integer.parseInt(c[1]);
String p = (args.length == 1) ? "changeit" : args[1];
passphrase = p.toCharArray();
} else {
System.out.println("Usage: java InstallCert <host>[:port] [passphrase]");
return;
}
  
File file = new File("jssecacerts");
if (file.isFile() == false) {
char SEP = File.separatorChar;
File dir = new File(System.getProperty("java.home") + SEP
+ "lib" + SEP + "security");
file = new File(dir, "jssecacerts");
if (file.isFile() == false) {
file = new File(dir, "cacerts");
}
}
System.out.println("Loading KeyStore " + file + "...");
InputStream in = new FileInputStream(file);
KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
ks.load(in, passphrase);
in.close();
  
SSLContext context = SSLContext.getInstance("TLS");
TrustManagerFactory tmf =
TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(ks);
X509TrustManager defaultTrustManager = (X509TrustManager)tmf.getTrustManagers()[0];
SavingTrustManager tm = new SavingTrustManager(defaultTrustManager);
context.init(null, new TrustManager[] {tm}, null);
SSLSocketFactory factory = context.getSocketFactory();
  
System.out.println("Opening connection to " + host + ":" + port + "...");
SSLSocket socket = (SSLSocket)factory.createSocket(host, port);
socket.setSoTimeout(10000);
try {
System.out.println("Starting SSL handshake...");
socket.startHandshake();
socket.close();
System.out.println();
System.out.println("No errors, certificate is already trusted");
} catch (SSLException e) {
System.out.println();
e.printStackTrace(System.out);
}
  
X509Certificate[] chain = tm.chain;
if (chain == null) {
System.out.println("Could not obtain server certificate chain");
return;
}
  
BufferedReader reader =
new BufferedReader(new InputStreamReader(System.in));
  
System.out.println();
System.out.println("Server sent " + chain.length + " certificate(s):");
System.out.println();
MessageDigest sha1 = MessageDigest.getInstance("SHA1");
MessageDigest md5 = MessageDigest.getInstance("MD5");
for (int i = 0; i < chain.length; i++) {
X509Certificate cert = chain[i];
System.out.println
(" " + (i + 1) + " Subject " + cert.getSubjectDN());
System.out.println(" Issuer " + cert.getIssuerDN());
sha1.update(cert.getEncoded());
System.out.println(" sha1 " + toHexString(sha1.digest()));
md5.update(cert.getEncoded());
System.out.println(" md5 " + toHexString(md5.digest()));
System.out.println();
}
  
System.out.println("Enter certificate to add to trusted keystore or 'q' to quit: [1]");
String line = reader.readLine().trim();
int k;
try {
k = (line.length() == 0) ? 0 : Integer.parseInt(line) - 1;
} catch (NumberFormatException e) {
System.out.println("KeyStore not changed");
return;
}
  
X509Certificate cert = chain[k];
String alias = host + "-" + (k + 1);
ks.setCertificateEntry(alias, cert);
  
OutputStream out = new FileOutputStream("jssecacerts");
ks.store(out, passphrase);
out.close();
  
System.out.println();
System.out.println(cert);
System.out.println();
System.out.println
("Added certificate to keystore 'jssecacerts' using alias '"
+ alias + "'");
}
  
private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();
  
private static String toHexString(byte[] bytes) {
StringBuilder sb = new StringBuilder(bytes.length * 3);
for (int b : bytes) {
b &= 0xff;
sb.append(HEXDIGITS[b >> 4]);
sb.append(HEXDIGITS[b & 15]);
sb.append(' ');
}
return sb.toString();
}
  
private static class SavingTrustManager implements X509TrustManager {
  
private final X509TrustManager tm;
private X509Certificate[] chain;
  
SavingTrustManager(X509TrustManager tm) {
this.tm = tm;
}
  
public X509Certificate[] getAcceptedIssuers() {
throw new UnsupportedOperationException();
}
  
public void checkClientTrusted(X509Certificate[] chain, String authType)
throws CertificateException {
throw new UnsupportedOperationException();
}
  
public void checkServerTrusted(X509Certificate[] chain, String authType)
throws CertificateException {
this.chain = chain;
tm.checkServerTrusted(chain, authType);
}
}
}

本文地址：https://blog.csdn.net/weixin_41143657/article/details/107282608