通过java通过https下载文件

Question

这是我现在从网上复制的代码，

/**
 * A simple example that uses HttpClient to perform a GET using Basic
 * Authentication. Can be run standalone without parameters.
 *
 * You need to have JSSE on your classpath for JDK prior to 1.4
 *
 * @author Michael Becke
 */
public class BasicAuthenticationExample {

    /**
     * Constructor for BasicAuthenticatonExample.
     */
    public BasicAuthenticationExample() {
        super();
    }

    public static void main(String[] args) throws Exception {
        HttpClient client = new HttpClient();

       client.getState().setCredentials(
                new AuthScope("login.website.com", 443),
                new UsernamePasswordCredentials("login id", "password")
                );

        GetMethod get = new GetMethod(
                "https://url to the file");

        get.setDoAuthentication( true );

        try {
            // execute the GET
            int status = client.executeMethod( get );

            // print the status and response
            System.out.println(status + "\n" + 
                    get.getResponseBodyAsString());

        } finally {
            // release any connection resources used by the method
            get.releaseConnection();
        }
    }
}

行

            int status = client.executeMethod( get );

因为我收到以下错误的

Exception in thread "main" 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 com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(Unknown Source)
at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Unknown Source)
at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Unknown Source)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(Unknown Source)
at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(Unknown Source)
at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Unknown Source)
at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(Unknown Source)
at com.sun.net.ssl.internal.ssl.AppOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.flush(Unknown Source)
at org.apache.commons.httpclient.HttpConnection.flushRequestOutputStream(HttpConnection.java:828)
at org.apache.commons.httpclient.HttpMethodBase.writeRequest(HttpMethodBase.java:2116)
at org.apache.commons.httpclient.HttpMethodBase.execute(HttpMethodBase.java:1096)
at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:398)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
at BasicAuthenticationExample.main(BasicAuthenticationExample.java:38)
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 com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.validate(Unknown Source)
at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source)
at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source)
... 18 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)
... 24 more

现在，此错误的原因当然是我的服务器发送的证书尚未在我的受信任证书列表中。 我的问题是如何将证书放入受信任列表。

谢谢 普拉纳贝什

Answer 1

您将需要一个包含要信任的证书的密钥库。 您可以使用Java的 keytool 命令来执行那。 有几种方法可以做到这一点：

• 将其添加到默认的 Java 密钥库（Windows 上的主目录或用户目录中的 .keystore）
• 设置系统属性 javax.net.ssl.trustStore 到备用密钥库的位置（例如 java -Djavax.net.ssl.trustStore=/path/to/keystore）
• 构建您自己的 SSLSocketFactory 实现可以以任何您想要的方式加载密钥库（此绝对是最复杂的）

密钥库只是一个包含可用于各种用途的密钥和/或证书的文件，在本例中是您的应用程序需要信任的证书。 Keytool 的使用方式如下：

keytool -importcert -file /path/to/certificate/file -keystore /path/to/keystore

对于其他命令行选项，只需运行

keytool -help

Answer 2

您可以使用 keytool 导入。

Answer 3

此页面似乎回答了您的问题：
将证书添加到您的 Java 密钥库

它引用了 Andres Sterbenz 的 InstallCert & 说明博客文章。

如果证书仅用于测试，您可能不想实际将其添加到受信任的存储中。 所以你也可以 禁用证书验证。