Java 播放Framework 2.1.0-使用Class.forName注册JDBC驱动程序时出现NoClassDefFoundError

我试图在Play 2.1.0中使用olap4j，但在让一些olap4j代码在Play控制器中工作时遇到了很大的困难，同样的代码在单独的Eclipse Java项目中工作得很好，因此我排除了olap4j或它所连接的XMLA服务器的任何问题。通过将JAR文件放在\lib文件夹中，我将olap4j JAR文件添加为非托管依赖项。我正在播放开发模式下运行

以下代码返回以下异常：

Java代码：

Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");

[RuntimeException: java.lang.NoClassDefFoundError: edu/emory/mathcs/backport/java/util/concurrent/Callable] 

Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");

java.sql.SQLException: No suitable driver found for jdbc:xmla:Server=http://localhost/OLAP/msmdpump.dll

package controllers;

import play.Play;
import play.mvc.*;
import org.olap4j.*;
import org.olap4j.metadata.Member;
import java.sql.*;

public class Test extends Controller {

public static Result index() {

    String server = "http://localhost/OLAP/msmdpump.dll";
    String user = "user";
    String password = "password";
    String result = "0";

    try {
        //Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        try {
            Connection connection = DriverManager.getConnection("jdbc:xmla:Server="+server, user, password);
        } catch (SQLException e) {
            result = e.getMessage();
        }
    } catch (ClassNotFoundException e) {
        result = e.getMessage();
    }

    return ok(result);
}
}

错误：

Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");

[RuntimeException: java.lang.NoClassDefFoundError: edu/emory/mathcs/backport/java/util/concurrent/Callable] 

Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");

java.sql.SQLException: No suitable driver found for jdbc:xmla:Server=http://localhost/OLAP/msmdpump.dll

package controllers;

import play.Play;
import play.mvc.*;
import org.olap4j.*;
import org.olap4j.metadata.Member;
import java.sql.*;

public class Test extends Controller {

public static Result index() {

    String server = "http://localhost/OLAP/msmdpump.dll";
    String user = "user";
    String password = "password";
    String result = "0";

    try {
        //Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        try {
            Connection connection = DriverManager.getConnection("jdbc:xmla:Server="+server, user, password);
        } catch (SQLException e) {
            result = e.getMessage();
        }
    } catch (ClassNotFoundException e) {
        result = e.getMessage();
    }

    return ok(result);
}
}

在进一步挖掘之后，我发现Play使用了自己的类加载器，因此我尝试了以下方法：

Java代码：

Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");

[RuntimeException: java.lang.NoClassDefFoundError: edu/emory/mathcs/backport/java/util/concurrent/Callable] 

Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");

java.sql.SQLException: No suitable driver found for jdbc:xmla:Server=http://localhost/OLAP/msmdpump.dll

package controllers;

import play.Play;
import play.mvc.*;
import org.olap4j.*;
import org.olap4j.metadata.Member;
import java.sql.*;

public class Test extends Controller {

public static Result index() {

    String server = "http://localhost/OLAP/msmdpump.dll";
    String user = "user";
    String password = "password";
    String result = "0";

    try {
        //Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        try {
            Connection connection = DriverManager.getConnection("jdbc:xmla:Server="+server, user, password);
        } catch (SQLException e) {
            result = e.getMessage();
        }
    } catch (ClassNotFoundException e) {
        result = e.getMessage();
    }

    return ok(result);
}
}

这似乎消除了NoClassDefFoundError错误，但引发了以下异常：

错误：

Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");

[RuntimeException: java.lang.NoClassDefFoundError: edu/emory/mathcs/backport/java/util/concurrent/Callable] 

Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");

java.sql.SQLException: No suitable driver found for jdbc:xmla:Server=http://localhost/OLAP/msmdpump.dll

package controllers;

import play.Play;
import play.mvc.*;
import org.olap4j.*;
import org.olap4j.metadata.Member;
import java.sql.*;

public class Test extends Controller {

public static Result index() {

    String server = "http://localhost/OLAP/msmdpump.dll";
    String user = "user";
    String password = "password";
    String result = "0";

    try {
        //Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        try {
            Connection connection = DriverManager.getConnection("jdbc:xmla:Server="+server, user, password);
        } catch (SQLException e) {
            result = e.getMessage();
        }
    } catch (ClassNotFoundException e) {
        result = e.getMessage();
    }

    return ok(result);
}
}

也许我需要在全局类中添加JDBC类注册？任何帮助都将不胜感激。org.olap4j.driver.xmla.XmlaOlap4jDriver的JavaDocs说明了以下内容，这正是我所关注的：

由于olap4j是JDBC的超集，因此可以像注册任何JDBC驱动程序一样注册此驱动程序： Class.forName（“org.olap4j.driver.xmla.XmlaOlap4jDriver”）； 然后使用前缀为“jdbc:xmla:”的URL创建连接

完整代码：

Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");

[RuntimeException: java.lang.NoClassDefFoundError: edu/emory/mathcs/backport/java/util/concurrent/Callable] 

Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");

java.sql.SQLException: No suitable driver found for jdbc:xmla:Server=http://localhost/OLAP/msmdpump.dll

package controllers;

import play.Play;
import play.mvc.*;
import org.olap4j.*;
import org.olap4j.metadata.Member;
import java.sql.*;

public class Test extends Controller {

public static Result index() {

    String server = "http://localhost/OLAP/msmdpump.dll";
    String user = "user";
    String password = "password";
    String result = "0";

    try {
        //Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        Play.application().classloader().loadClass("org.olap4j.driver.xmla.XmlaOlap4jDriver");
        try {
            Connection connection = DriverManager.getConnection("jdbc:xmla:Server="+server, user, password);
        } catch (SQLException e) {
            result = e.getMessage();
        }
    } catch (ClassNotFoundException e) {
        result = e.getMessage();
    }

    return ok(result);
}
}

根据，您的第一种方法应该可以正常工作，例如：

Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");

你所犯的错误

java.lang.NoClassDefFoundError: edu/emory/mathcs/backport/java/util/concurrent/Callable

---

这意味着您还需要将

backport util concurrent.jar

添加到类路径中（如中所述）。我想在那之后应该可以用了。该jar是Backport并发Util jar，可用。将其也放入lib文件夹。

看起来您同时使用了olap4j和olap4j-jdk14。你只需要其中一个。

上帝保佑你！它正在工作，我还需要Retroweaver（）。Eclipse&Play集成似乎存在一些问题，因为非web Java项目在Eclipse中没有额外的依赖项。非常感谢您的帮助。np:）需要这样的库有点奇怪，就好像您运行在某个遗留系统中一样(