Java 如何从URL下载.jar文件

我必须从远程kie maven存储库下载一个.jar文件，该存储库需要使用我的java代码进行身份验证。 代码如下

String url = "http://localhost:18080/kiewb/maven2/group/artifact/version/file.jar";
        UrlResource urlResource = (UrlResource) resources.newUrlResource(url);
        urlResource.setUsername("username"); 
        urlResource.setPassword("password");

        urlResource.setBasicAuthentication("enabled");

    InputStream is = urlResource.getInputStream();

但是，这是投掷

Exception in thread "main" java.io.IOException: Server returned HTTP response code: 500 for URL:http://localhost:18080/kiewb/maven2/group/artifact/version/file.jar
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1839)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1440)
    at url.main(url.java:47)

在maven repo所在的服务器中，我得到了以下错误。 我的服务器是Wildfly10

ERROR [io.undertow.request] (default task-58) UT005023: Exception handling request to /kiewb/maven2/group/artifact/version/file.jar: java.lang.ArrayIndexOutOfBoundsException: 1
        at org.uberfire.ext.security.server.BasicAuthSecurityFilter.authenticate(BasicAuthSecurityFilter.java:112)
        at org.uberfire.ext.security.server.BasicAuthSecurityFilter.doFilter(BasicAuthSecurityFilter.java:69)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.uberfire.ext.security.server.SecureHeadersFilter.doFilter(SecureHeadersFilter.java:69)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at org.uberfire.ext.security.server.SecurityIntegrationFilter.doFilter(SecurityIntegrationFilter.java:57)
        at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
        at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
        at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
        at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
        at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
        at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.security.handlers.AuthenticationConstraintHandler.handleRequest(AuthenticationConstraintHandler.java:53)
        at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
        at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
        at io.undertow.servlet.handlers.security.ServletSecurityConstraintHandler.handleRequest(ServletSecurityConstraintHandler.java:59)
        at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
        at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
        at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
        at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
        at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)
        at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)
        at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
        at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
        at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
        at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
        at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
        at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
        at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
        at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
        at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
        at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
        at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
        at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)
        at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
        at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:805)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)

---

我可以通过直接点击浏览器中的URL下载同一个jar。

尝试另一种下载方式。注意，它应该是Java8

public void downloadFile(String fromUrl, String localFileName) throws IOException {
    File localFile = new File(localFileName);
    if (localFile.exists()) {
        localFile.delete();
    }
    localFile.createNewFile();
    URL url = new URL(fromUrl);
    OutputStream out = new BufferedOutputStream(new FileOutputStream(localFileName));
    URLConnection conn = url.openConnection();
    String encoded = Base64.getEncoder().encodeToString(("username"+":"+"password").getBytes(StandardCharsets.UTF_8));  //Java 8
    conn.setRequestProperty("Authorization", "Basic "+ encoded);
    InputStream in = conn.getInputStream();
    byte[] buffer = new byte[1024];

    int numRead;
    while ((numRead = in.read(buffer)) != -1) {
        out.write(buffer, 0, numRead);
    }
    if (in != null) {
        in.close();
    }
    if (out != null) {
        out.close();
    }
}

---

只需将最新文件重命名为应用程序中的文件名，然后下载即可。上面的例子对于启动器来说非常好，因为它删除了旧文件

响应代码是500。这意味着服务器端有一个错误。检查服务器日志，首先解决该问题。HTTP响应代码

500

为“内部服务器错误”。因此，您很可能在服务器上遇到问题。尝试使用

curl

或其他命令行下载文件。从浏览器下载时是否要求任何身份验证？是否使用空密码？在浏览器中下载时报告了一个类似的问题，它不要求任何身份验证。我可以从同一目录中获取最新更新的文件吗？您的意思是“同一目录中的最新更新文件”？例如，如果我在一个目录中有3个文件，我想下载最后更新的文件，表示文件不基于名称，但在时间上有所修改。我想这取决于你的服务器。您的服务器应该有一个API来获取最新的文件URL，然后从最新的文件URL，您可以下载最新的文件。或者您可以在服务器中提供API以下载最新的文件。差不多。在服务器上，您可以找到最新的文件并将其提供给客户端