利用JDBC进行mysql到opengauss的数据迁移

记录一下数据库实验中比较难的一个，实在是比较费脑筋。

任务：将一种数据类型从mysql上迁移到opengauss上 我在这里以视图为例

既然用JDBC连接，那么要导入mysql和opengauss的驱动

如下图所示，去官网上下载就可以了

下面为opengauss的连接 需要改的就是下面的ip地址（可以在你的数据库上用ifconfig查看），还有连接的具体数据库，还有你用户的名字和密码都需要根据自己的来改

 //gauss connect
    static final String JDBC_DRIVER = "org.postgresql.Driver";
    static final String gauss_URL = "jdbc:postgresql://ip address/DB";
 static final String gauss_user = "name";
    static final String gauss_pass = "password";

下面为mysql的连接， 同样一些基本信息需要填你自己的，值得一提的是最后一个驱动如果你的mysql是8.0以上则要加中间那个cj

static final String databaseName = "lab4";//数据库名
    static final String mysql_user = "";//使用管理员账号启动
    static final String mysql_pwd = " ";//数据库密码
    static final String mysql_URL = "jdbc:mysql://localhost:3306/" + databaseName + "?useSSL=false&serverTimezone=UTC";
    static final String mysql_DRIVER = "com.mysql.cj.jdbc.Driver";

 下面为代码的关键 包括sql语句的定义 sql语句的执行，尤其要注意 思想是先从opengauss里提取出来数据，然后作为mysql语句的执行内容，一般会有字符串和变量不匹配的问题，要进行一下转义

 String sql;//提取
                sql = "SELECT table_name,table_schema,view_definition,check_option,is_updatable FROM information_schema.views where table_schema=\'lab4\' ;";
                String g_sql;
                g_sql="select * from test";
                ResultSet rs=gauss_stmt.executeQuery(g_sql);
                ResultSet resultset = mysql_stmt.executeQuery(sql);
                while (resultset.next()) {
                    String view_def = resultset.getString("VIEW_DEFINITION");
	view_def=view_def.replace("`","");
                  
String a=" create view vi as %s;";
     String b=String.format(a,view_def);
 System.out.println(b);
    gauss_stmt.execute(b);

下面为完整代码

import java.sql.*;
public class lab4 {
    //gauss connect
    static final String JDBC_DRIVER = "org.postgresql.Driver";
    static final String gauss_URL = "jdbc:postgresql://192.168.176.154:5432/demo";
    // 数据库的用户名与密码，需要根据自己的设置
    static final String gauss_user = "dbuser";
    static final String gauss_pass = "Gauss#3demo";
    //mysql connect
    static final String databaseName = "lab4";//数据库名
    static final String mysql_user = "root";//使用管理员账号启动
    static final String mysql_pwd = "ljl050505 ";//数据库密码
    static final String mysql_URL = "jdbc:mysql://localhost:3306/" + databaseName + "?useSSL=false&serverTimezone=UTC";
    static final String mysql_DRIVER = "com.mysql.cj.jdbc.Driver";


        public static void main(String[]args)throws Exception {
            Connection mysql_conn = null;
            Statement mysql_stmt = null;
            Connection gauss_conn = null;
            Statement gauss_stmt = null;
            try {
                Class.forName(mysql_DRIVER);
                System.out.println("connect mysql DB");
                mysql_conn = DriverManager.getConnection(mysql_URL, mysql_user, mysql_pwd);
                mysql_stmt = mysql_conn.createStatement();
                Class.forName(JDBC_DRIVER);
                System.out.println("connect opengauss");
                gauss_conn = DriverManager.getConnection(gauss_URL, gauss_user, gauss_pass);
                gauss_stmt=gauss_conn.createStatement();

                String sql;//提取
                sql = "SELECT table_name,table_schema,view_definition,check_option,is_updatable FROM information_schema.views where table_schema=\'lab4\' ;";
                String g_sql;
                g_sql="select * from test";
                ResultSet rs=gauss_stmt.executeQuery(g_sql);
                ResultSet resultset = mysql_stmt.executeQuery(sql);
                while (resultset.next()) {
                    String view_def = resultset.getString("VIEW_DEFINITION");
	view_def=view_def.replace("`","");
                  
String a=" create view vi as %s;";
     String b=String.format(a,view_def);
 System.out.println(b);
    gauss_stmt.execute(b);
                }

while(rs.next()){
 String g_name=rs.getString("name");
                    String g_location=rs.getString("location");
                    System.out.println("name"+g_name);
                    System.out.println("location"+g_location);
}
                resultset.close();
                mysql_stmt.close();
                mysql_conn.close();
                gauss_stmt.close();
                gauss_conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } catch (Exception e1) {
                e1.printStackTrace();
            } finally {
                try {
                    if (mysql_stmt != null) mysql_stmt.close();
                } catch (SQLException e2) {

                }
            }
            try {
                if (mysql_conn != null) mysql_conn.close();
            } catch (SQLException e3) {
                e3.printStackTrace();
            }
            System.out.println("goodbye");

        }
    }

有问题可以私信