Derby 数据库介绍(2)--使用

本文主要介绍 Derby 的基本使用(简介可参考:Derby 数据库介绍(1)--简介)，文中所使用到的软件版本：Java 1.8.0_341、Derby 10.14.2.0。

1、嵌入模式

直接使用 JDBC 连接数据库，可创建和启动数据库。

1.1、内存数据库

@Test
public void embeddedMemory() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:memory:myDb;create=true", user, "");
    business(con, user);
    con.close();
}

private void business(Connection con, String user) throws SQLException {
    String tableName = "a_student";
    Statement st = con.createStatement();
    String sql = "select 1 from sys.sysTABLES a,sys.sysschemas b where a.schemaid=b.schemaid and upper(b.schemaname)=? and upper(a.tablename)=?";
    PreparedStatement pst = con.prepareStatement(sql);
    pst.setString(1, user.toUpperCase());
    pst.setString(2, tableName.toUpperCase());
    ResultSet rs = pst.executeQuery();
    if (!rs.next()) {//表不存在则创建并初始化数据，这里根据业务需要进行操作
        st.executeUpdate("create table " + tableName + "(id int, name varchar(32))");
        st.executeUpdate("insert into " + tableName + "(id,name) values (1,'李白')");
        st.executeUpdate("insert into " + tableName + "(id,name) values (2,'杜甫')");
    }

    rs = st.executeQuery("select * from " + tableName);
    while (rs.next()) {
        log.info("id={},name={}", rs.getInt("id"), rs.getString("name"));
    }
}

1.2、文件数据库

@Test
public void embeddedFile() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:d:/temp/myDb;create=true", user, "");
    business(con, user);
    con.close();
}

1.3、资源数据库

@Test
public void embeddedJar() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:classpath:myDb", user, "");
    business(con, user);
    con.close();
}

jar 包不在 classpath 之中：

@Test
public void embeddedJar2() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:jar:(d:/temp/my.jar)myDb", user, "");
    business(con, user);
    con.close();
}

2、服务器模式

在服务端启动 Derby 数据库服务：

cd ${DERBY_HOME}/bin
NetworkServerControl.bat start -p 1527 -noSecurityManager

客户端通过 JDBC 访问 Derby 服务。

2.1、内存数据库

@Test
public void networkMemory() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/memory:myDb;create=true", user, "123456");
    business(con, user);
    con.close();
}

2.2、文件数据库

@Test
public void networkFile() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/d:/temp/myDb;create=true", user, "123456");
    business(con, user);
    con.close();
}

2.3、资源数据库

@Test
public void networkJar() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/classpath:myDb", user, "123");
    business(con, user);
    con.close();
}

jar 包不在 classpath 之中：

@Test
public void networkJar2() throws SQLException {
    String user = "admin";
    Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/jar:(d:/temp/my.jar)myDb", user, "123");
    business(con, user);
    con.close();
}

3、混合模式

应用通过代码的方式启动数据库服务，应用内访问数据库可以使用进程模式，其他应用通过服务器模式访问。

@Test
public void networkServerControl() throws Exception {
    NetworkServerControl server = new NetworkServerControl(InetAddress.getByName("0.0.0.0"), 1527);
    server.start (null);

    CountDownLatch countDownLatch = new CountDownLatch(1);
    new Thread(() -> {
        try {
            //模拟其他应用访问
            networkMemory();
        } catch (Exception e) {
            e.printStackTrace();
        }
        countDownLatch.countDown();
    }).start();

    countDownLatch.await();
    server.shutdown();
}

 

 

完整代码：

package com.abc.demo.db;

import lombok.extern.slf4j.Slf4j;
import org.apache.derby.drda.NetworkServerControl;
import org.junit.Test;

import java.net.InetAddress;
import java.sql.*;
import java.util.concurrent.CountDownLatch;

@Slf4j
public class DerbyCae {
    @Test
    public void embeddedMemory() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:memory:myDb;create=true", user, "");
        business(con, user);
        con.close();
    }

    @Test
    public void embeddedFile() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:d:/temp/myDb;create=true", user, "");
        business(con, user);
        con.close();
    }

    @Test
    public void embeddedJar() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:classpath:myDb", user, "");
        business(con, user);
        con.close();
    }

    @Test
    public void embeddedJar2() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:jar:(d:/temp/my.jar)myDb", user, "");
        business(con, user);
        con.close();
    }

    @Test
    public void networkMemory() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/memory:myDb;create=true", user, "123456");
        business(con, user);
        con.close();
    }

    @Test
    public void networkFile() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/d:/temp/myDb;create=true", user, "123456");
        business(con, user);
        con.close();
    }

    @Test
    public void networkJar() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/classpath:myDb", user, "123");
        business(con, user);
        con.close();
    }

    @Test
    public void networkJar2() throws SQLException {
        String user = "admin";
        Connection con = JdbcUtil.getConnection("org.apache.derby.jdbc.ClientDriver", "jdbc:derby://localhost:1527/jar:(d:/temp/my.jar)myDb", user, "123");
        business(con, user);
        con.close();
    }

    @Test
    public void networkServerControl() throws Exception {
        NetworkServerControl server = new NetworkServerControl(InetAddress.getByName("0.0.0.0"), 1527);
        server.start (null);

        CountDownLatch countDownLatch = new CountDownLatch(1);
        new Thread(() -> {
            try {
                //模拟其他应用访问
                networkMemory();
            } catch (Exception e) {
                e.printStackTrace();
            }
            countDownLatch.countDown();
        }).start();

        countDownLatch.await();
        server.shutdown();
    }

    private void business(Connection con, String user) throws SQLException {
        String tableName = "a_student";
        Statement st = con.createStatement();
        String sql = "select 1 from sys.sysTABLES a,sys.sysschemas b where a.schemaid=b.schemaid and upper(b.schemaname)=? and upper(a.tablename)=?";
        PreparedStatement pst = con.prepareStatement(sql);
        pst.setString(1, user.toUpperCase());
        pst.setString(2, tableName.toUpperCase());
        ResultSet rs = pst.executeQuery();
        if (!rs.next()) {//表不存在则创建并初始化数据，这里根据业务需要进行操作
            st.executeUpdate("create table " + tableName + "(id int, name varchar(32))");
            st.executeUpdate("insert into " + tableName + "(id,name) values (1,'李白')");
            st.executeUpdate("insert into " + tableName + "(id,name) values (2,'杜甫')");
        }

        rs = st.executeQuery("select * from " + tableName);
        while (rs.next()) {
            log.info("id={},name={}", rs.getInt("id"), rs.getString("name"));
        }
    }
}

package com.abc.demo.db;

import lombok.extern.slf4j.Slf4j;

import java.sql.*;


@Slf4j
public class JdbcUtil {
    private JdbcUtil() {}

    public static Connection getConnection(String driver, String url, String username, String password) {
        Connection con = null;
        try {
            Class.forName(driver);
            con = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException | SQLException e) {
            log.warn("url={},username={},password={}", url, username, password);
            e.printStackTrace();
        }
        return con;
    }
}