使用 Mysql ClusterJ jar 文件连接到 NDB 集群

Question

我按照 ClusterJ 教程 here 中的说明使用 NDB api 连接到 MySQL NDB 集群。下面是我现在正在做的示例代码：

Main.java

import com.mysql.clusterj.ClusterJHelper;
import com.mysql.clusterj.SessionFactory;
import com.mysql.clusterj.Session;
import com.mysql.clusterj.Query;
import com.mysql.clusterj.query.QueryBuilder;
import com.mysql.clusterj.query.QueryDomainType;
import java.io.File;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.*;
import java.util.Properties;
import java.util.List;

public class Main {
    public static void main (String[] args) throws
    java.io.FileNotFoundException,java.io.IOException {
     // Load the properties from the clusterj.properties file
     File propsFile = new File("clusterj.properties");
     InputStream inStream = new FileInputStream(propsFile);
     Properties props = new Properties();
     props.load(inStream);
     //Used later to get user input
     BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

     // Create a session (connection to the database)
     SessionFactory factory = ClusterJHelper.getSessionFactory(props);
     Session session = factory.getSession();

    // Create and initialize an Employee
     Employee newEmployee = session.newInstance(Employee.class);
     newEmployee.setId(988);
     newEmployee.setFirst("John");
     newEmployee.setLast("Jones");
     newEmployee.setStarted("1 February 2009");
     newEmployee.setDepartment(666);

     // Write the Employee to the database
     session.persist(newEmployee);
}
}

我在尝试运行时遇到以下错误：

java.lang.UnsatisfiedLinkError: no ndbclient in java.library.path
    at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1867)
    at java.lang.Runtime.loadLibrary0(Runtime.java:870)
    at java.lang.System.loadLibrary(System.java:1122)
    at com.mysql.clusterj.tie.ClusterConnectionServiceImpl.loadSystemLibrary(ClusterConnectionServiceImpl.java:68)
    at com.mysql.clusterj.tie.ClusterConnectionServiceImpl.create(ClusterConnectionServiceImpl.java:87)
    at com.mysql.clusterj.core.SessionFactoryImpl.createClusterConnection(SessionFactoryImpl.java:335)
    at com.mysql.clusterj.core.SessionFactoryImpl.createClusterConnectionPool(SessionFactoryImpl.java:288)
    at com.mysql.clusterj.core.SessionFactoryImpl.<init>(SessionFactoryImpl.java:211)
    at com.mysql.clusterj.core.SessionFactoryImpl.getSessionFactory(SessionFactoryImpl.java:146)
    at com.mysql.clusterj.core.SessionFactoryServiceImpl.getSessionFactory(SessionFactoryServiceImpl.java:36)
    at com.mysql.clusterj.core.SessionFactoryServiceImpl.getSessionFactory(SessionFactoryServiceImpl.java:27)
    at com.mysql.clusterj.ClusterJHelper.getSessionFactory(ClusterJHelper.java:72)
    at com.mysql.clusterj.ClusterJHelper.getSessionFactory(ClusterJHelper.java:57)
    at com.pkg.mysql.Main.main(Main.java:27)

Answer 1

错误发生是因为 ClusterJ 需要 java 类路径中的 ndb_engine.so 文件。

参考Link：http://ftp.nchu.edu.tw/MySQL/doc/ndbapi/en/mccj-getting.html

一旦我指定了路径，我就可以运行程序。

# steps to compile and run the ndb java program on linux
javac -classpath /home/user1/clusterj-7.6.8.jar:. Main.java Employee.java
java -classpath /home/user1/clusterj-7.6.8.jar:. -Djava.library.path=/usr/lib64/mysql Main

我仍然找不到在 Windows 环境中解决它的方法。

Answer 2

添加为 vm 参数或运行包括以下路径

对于Mac：

-Djava.library.path="/usr/local/mysql-{cluster-version}/lib/"

对于Windows：

search for library path and replace inside double quotes

使用 Mysql ClusterJ jar 文件连接到 NDB 集群

Use the Mysql ClusterJ jar file to connect to NDB cluster

java

mysql

scala

mysql-cluster