Question

我刚开始玩Crate（版本crate-0.55.2）。我想通过JDBC连接到Crate。这是我的示例java代码：

 if (!string.IsNullOrEmpty(Request.QueryString["Lang"]))
    {
        HttpCookie myCookie = (HttpCookie)Request.Cookies["cLang"];
        if (myCookie != null)
        {
            if (myCookie["Lang"] != Request.QueryString["Lang"].ToString())
            {
                myCookie["Lang"] = Request.QueryString["Lang"].ToString();
                myCookie.Expires = DateTime.Now.AddYears(1);
                Response.Cookies.Add(myCookie);

                System.Threading.Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo(Request.QueryString["Lang"]);
                System.Threading.Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.CreateSpecificCulture(Request.QueryString["Lang"]);
                Response.Redirect(Request.Url.AbsoluteUri);
            }
        }
        else
        {
            string strLang = Request.QueryString["Lang"];
            myCookie = new HttpCookie("cLang");
            myCookie.Values.Add("Lang", strLang);
            myCookie.Expires = DateTime.Now.AddYears(1);
            Response.Cookies.Add(myCookie);
            System.Threading.Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo(strLang);
            System.Threading.Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.CreateSpecificCulture(strLang);
        }

    }

我已经添加了库＆＃34; crate-jdbc-standalone-1.9.3.jar＆＃34;到我的Java Build Path。我已经改变了＆＃34; transport.tcp.port＆＃34; ＆＃34; crate.yml＆＃34;中的4301文件。（所有其他配置都没有改变，只有这个端口）。当我运行我的Java代码时，我在Eclipse中获得了以下输出：

import java.sql.*;
//import io.crate.*;
public class CrateTestDemo {
    private Connection connection;
    public static void main(String[] args) {    
        CrateTestDemo t = new CrateTestDemo();
        try {
            t.setupDatabase();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
            System.out.println("e="+e.getMessage());
        }
    }
    public void setupDatabase() throws ClassNotFoundException, SQLException {
        Class.forName("io.crate.client.jdbc.CrateDriver");
        connection = DriverManager.getConnection("crate://127.0.0.1:4301");
    }
}

在＆＃34; crate.log＆＃34;文件我得到了这个：

log4j:WARN No appenders could be found for logger (io.crate.shade.org.elasticsearch.common.compress.lzf).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
java.sql.SQLException: Connect to '127.0.0.1:4301' failed
    at io.crate.client.jdbc.CrateConnection.connect(CrateConnection.java:58)
    at io.crate.client.jdbc.CrateDriver.connect(CrateDriver.java:67)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:270)
    at CrateTestDemo.setupDatabase(CrateTestDemo.java:19)
    at CrateTestDemo.main(CrateTestDemo.java:10)
Caused by: io.crate.shade.org.elasticsearch.client.transport.NoNodeAvailableException: None of the configured nodes are available: []
    at io.crate.shade.org.elasticsearch.client.transport.TransportClientNodesService.ensureNodesAreAvailable(TransportClientNodesService.java:309)
    at io.crate.shade.org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:201)
    at io.crate.client.InternalCrateClient.execute(InternalCrateClient.java:87)
    at io.crate.client.InternalCrateClient.execute(InternalCrateClient.java:70)
    at io.crate.client.InternalCrateClient.sql(InternalCrateClient.java:59)
    at io.crate.client.CrateClient.sql(CrateClient.java:152)
    at io.crate.client.jdbc.CrateStatement.execute(CrateStatement.java:65)
    at io.crate.client.jdbc.CrateStatementBase.executeQuery(CrateStatementBase.java:37)
    at io.crate.client.jdbc.CrateDatabaseMetaData.getDatabaseProductVersion(CrateDatabaseMetaData.java:79)
    at io.crate.client.jdbc.CrateConnection.connect(CrateConnection.java:56)
    ... 5 more
e=Connect to '127.0.0.1:4301' failed

有人知道为了让我的小Java代码运行必须做些什么吗？感谢。

Answer 1

嗯..好吧..我应该在检查兼容性之前：）

我已将其更改为较新的库＆＃34; crate-jdbc-standalone-1.13.0.jar＆＃34;，现在可以正常使用。

另见：https://github.com/crate/crate/issues/3786 和https://github.com/crate/crate-jdbc/tree/1.13#compatibility

crate.io jdbc连接失败

1 个答案: