记一次使用java代码的方式从mysql数据库导入多张表到postgresql数据库的记录

由于本人是一个java开发人员，所以用了java的方式

步骤
1 。拷贝一些基础数据 连接两个数据库 ，拷贝能考的
需要注意的是mysql数据库的时间格式和postgresql 不一样，我这边做了转换。

//声明Connection对象
Connection con;
String driver = "com.mysql.cj.jdbc.Driver";
String url = "jdbc:mysql://localhost/test?serverTimezone=GMT%2B8";
String user = "root";
String password = "root";

Connection con2;
String driver2 = "org.postgresql.Driver";
String url2 = "jdbc:postgresql://localhost:5432/escort_dh";
String user2 = "postgresql";
String password2 = "root";
try {
//加载驱动程序
Class.forName(driver);
con = DriverManager.getConnection(url,user,password);
Class.forName(driver2);
con2 = DriverManager.getConnection(url2,user2,password2);
if(!con.isClosed()){
System.out.println("成功连接到数据库1!");
}
if (!con2.isClosed()){
System.out.println("成功连接到数据库2!");
}
//2.创建statement类对象，用来执行SQL语句！！
Statement statement = con.createStatement();
//要执行的SQL语句
String sql = "select no,card,inputTime,removed,enabled from escortgoods";
//要执行的SQL语句
String sql2 = "insert into et_escort_goods (id,no,type,node,card_ids,create_time,create_by,update_time,update_by,removed,enabled) " +
"values(?,?,null,null,?,?,1,null,null,?,?)";
//3.ResultSet类，用来存放获取的结果集！！
ResultSet rs = statement.executeQuery(sql);
PreparedStatement pst = con2.prepareStatement(sql2);
int i = 226;
while(rs.next()){

System.out.println(i);
System.out.print(rs.getLong(1)+" ");
System.out.print(rs.getString(2)+" ");
System.out.print(rs.getString(3)+" ");
System.out.print(rs.getLong(4)+" ");
System.out.print(rs.getLong(5)+" ");
//            	System.out.print(rs.getString(2)+"\n");
++i;
String str = rs.getString(3);

pst.setLong(1,i);

pst.setString(2,rs.getString(1));
pst.setString(3,rs.getString(2));

//时间转换

if (str==null){
pst.setDate(4,rs.getDate(3));
}else {
DateFormat format= new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date=format.parse(str);
Timestamp sqlDate = new Timestamp(date.getTime());
pst.setTimestamp(4,sqlDate);
}

boolean fouth  = true;
if (rs.getLong(4)==0){
fouth= false;
}
boolean fifth = true;
if (rs.getLong(5)==0){
fifth = false;
}
pst.setBoolean(5,fouth);
pst.setBoolean(6,fifth);

pst.executeUpdate();

}
System.out.println("完成");
rs.close();
con.close();
con2.close();
}catch(ClassNotFoundException e) {
//数据库驱动类异常处理
System.out.println("对不起,找不到驱动程序!");
e.printStackTrace();
} catch(SQLException e) {
//数据库连接失败异常处理
e.printStackTrace();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}

步骤 2 对外键进行拷贝，首先搞清楚外键的关系，我这边由于mysql表中的数据是uuid加密的，所以无法对应拷贝。所以我这边比较麻烦

//声明Connection对象
Connection con;
String driver = "com.mysql.cj.jdbc.Driver";
String url = "jdbc:mysql://localhost/test?serverTimezone=GMT%2B8";
String user = "root";
String password = "root";

Connection con2;
String driver2 = "org.postgresql.Driver";
String url2 = "jdbc:postgresql://localhost:5432/test";
String user2 = "postgresql";
String password2 = "root";
try {
//加载驱动程序
Class.forName(driver);
con = DriverManager.getConnection(url,user,password);
Class.forName(driver2);
con2 = DriverManager.getConnection(url2,user2,password2);
if(!con.isClosed()){
System.out.println("成功连接到数据库1!");
}
if (!con2.isClosed()){
System.out.println("成功连接到数据库2!");
}
//2.创建statement类对象，用来执行SQL语句！！
Statement statement = con.createStatement();
//要执行的SQL语句
String sql = "select card,goods from card";
//要执行的SQL语句
String sql2 = "UPDATE good SET  id = ? WHERE  no = ?";
//3.ResultSet类，用来存放获取的结果集！！
ResultSet rs = statement.executeQuery(sql);
PreparedStatement pst = con2.prepareStatement(sql2);
int i = 1;
while(rs.next()){

System.out.println(i);
System.out.print(rs.getString(1)+" ");
System.out.print(rs.getString(2)+" ");
++i;

//                Connection   con3 = DriverManager.getConnection(url,user,password);
//2.创建statement类对象，用来执行SQL语句！！

String sql3 = "select no from escortgoods where id = ? ";
PreparedStatement preparedStatement = con.prepareStatement(sql3);
preparedStatement.setString(1,rs.getString(2));
ResultSet resultSet = preparedStatement.executeQuery();

int id = 0 ;
while (resultSet.next()){
//                    Connection   con4 = DriverManager.getConnection(url2,user2,password2);
//2.创建statement类对象，用来执行SQL语句！！

String sql4 = "select idfrom goodswhere no= ? ";
//            	System.out.print(rs.getString(2)+"\n");
PreparedStatement preparedStatement1 = con2.prepareStatement(sql4);
preparedStatement1.setString(1,resultSet.getString(1));
ResultSet resultSet1 = preparedStatement1.executeQuery();
while (resultSet1.next()){
id = resultSet1.getInt(1);
break;

}
break;
}

System.out.println("id:"+id);

if (id==0){
continue;
}
pst.setInt(1,id);
pst.setString(2,rs.getString(1));

pst.executeUpdate();

}
System.out.println("完成");
rs.close();
con.close();
con2.close();
}catch(ClassNotFoundException e) {
//数据库驱动类异常处理
System.out.println("对不起,找不到驱动程序!");
e.printStackTrace();
} catch(SQLException e) {
//数据库连接失败异常处理
e.printStackTrace();
}catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}

**
基本上就完成了，这边需要注意的是·拷贝外键时由于要查询多次sql，查出来的值有可能是null值，所以此时如果数据库不允许空值的存在，自己写一个判断，使用continue;关键词跳出本次循环，自己把握。

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