“PKIX 路径构建失败”和“无法找到请求目标的有效证书路径”

我正在尝试使用 twitter4j 库为我的 java 项目获取推文，该项目在幕后使用java.net.HttpURLConnection（如堆栈跟踪中所示）。第一次运行时，我收到有关证书的错误sun.security.validator.ValidatorException and sun.security.provider.certpath.SunCertPathBuilderException。然后我通过以下方式添加了 Twitter 证书：

C:\Program Files\Java\jdk1.7.0_45\jre\lib\security>keytool -importcert -trustcacerts -file PathToCert -alias ca_alias -keystore "C:\Program Files\Java\jdk1.7.0_45\jre\lib\security\cacerts"

但没有成功。以下是获取推文的过程：

public static void main(String[] args) throws TwitterException {
    ConfigurationBuilder cb = new ConfigurationBuilder();
    cb.setDebugEnabled(true)
        .setOAuthConsumerKey("myConsumerKey")
        .setOAuthConsumerSecret("myConsumerSecret")
        .setOAuthAccessToken("myAccessToken")
        .setOAuthAccessTokenSecret("myAccessTokenSecret");
    
    TwitterFactory tf = new TwitterFactory(cb.build());
    Twitter twitter = tf.getInstance();
    
    try {
        Query query = new Query("iphone");
        QueryResult result;
        result = twitter.search(query);
        System.out.println("Total amount of tweets: " + result.getTweets().size());
        List<Status> tweets = result.getTweets();
        
        for (Status tweet : tweets) {
            System.out.println("@" + tweet.getUser().getScreenName() + " : " + tweet.getText());
        }
    } catch (TwitterException te) {
        te.printStackTrace();
        System.out.println("Failed to search tweets: " + te.getMessage());
    }

这是错误：

sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
Relevant discussions can be found on the Internet at:
    http://www.google.co.jp/search?q=d35baff5 or
    http://www.google.co.jp/search?q=1446302e
TwitterException{exceptionCode=[d35baff5-1446302e 43208640-747fd158 43208640-747fd158 43208640-747fd158], statusCode=-1, message=null, code=-1, retryAfter=-1, rateLimitStatus=null, version=3.0.5}
    at twitter4j.internal.http.HttpClientImpl.request(HttpClientImpl.java:177)
    at twitter4j.internal.http.HttpClientWrapper.request(HttpClientWrapper.java:61)
    at twitter4j.internal.http.HttpClientWrapper.get(HttpClientWrapper.java:81)
    at twitter4j.TwitterImpl.get(TwitterImpl.java:1929)
    at twitter4j.TwitterImpl.search(TwitterImpl.java:306)
    at jku.cc.servlets.TweetsAnalyzer.main(TweetsAnalyzer.java:38)
Caused by: 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(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source)
    at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
    at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
    at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source)
    at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source)
    at sun.security.ssl.Handshaker.processLoop(Unknown Source)
    at sun.security.ssl.Handshaker.process_record(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source)
    at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
    at java.net.HttpURLConnection.getResponseCode(Unknown Source)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(Unknown Source)
    at twitter4j.internal.http.HttpResponseImpl.<init>(HttpResponseImpl.java:34)
    at twitter4j.internal.http.HttpClientImpl.request(HttpClientImpl.java:141)
    ... 5 more
Caused by: 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.validator.PKIXValidator.doBuild(Unknown Source)
    at sun.security.validator.PKIXValidator.engineValidate(Unknown Source)
    at sun.security.validator.Validator.validate(Unknown Source)
    at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source)
    at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source)
    at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source)
    ... 20 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(Unknown Source)
    at java.security.cert.CertPathBuilder.build(Unknown Source)
    ... 26 more
Failed to search tweets: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

1. 在浏览器中转到 URL：

• firefox - 单击 HTTPS 证书链（URL 地址旁边的锁图标）。点击"more info" > "security" > "show certificate" > "details" > "export.."。选择名称并选择文件类型 example.cer
• chrome - 单击地址栏中地址左侧的站点图标，选择“证书”->“详细信息”->“导出”并以“Der 编码二进制，单个证书”格式保存。

2. 现在您已经有了带有密钥库的文件，并且必须将其添加到您的 JVM 中。确定 cacerts 文件的位置，例如。C:\Program Files (x86)\Java\jre1.6.0_22\lib\security\cacerts.

3. 接下来导入example.cer在命令行中将文件写入 cacerts（可能需要管理员命令提示符）：

keytool -import -alias example -keystore "C:\Program Files (x86)\Java\jre1.6.0_22\lib\security\cacerts" -file example.cer

系统会要求您输入密码，默认密码是changeit

重新启动 JVM/PC。

source: http://magicmonster.com/kb/prg/java/ssl/pkix_path_building_failed.html http://magicmonster.com/kb/prg/java/ssl/pkix_path_building_failed.html