数据库事务管理级别

package Test;


import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;


import javax.sql.ConnectionPoolDataSource;


import org.junit.Test;


import com.mysql.jdbc.Connection;


public class testArrifire {
@Test
public void Testshow() throws Exception {
String url = "jdbc:mysql:///bank";
String Driverclass = "com.mysql.jdbc.Driver";
String user = "root";
String password = "123456";
Class.forName(Driverclass);
Connection conn = (Connection) DriverManager.getConnection(url, user, password);
conn.setTransactionIsolation(Connection.TRANSACTION_READ_UNCOMMITTED);
// conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED);
conn.setAutoCommit(false);
String sql = "update customers SET balance=balance-500 where id=1";
PreparedStatement ps = conn.prepareStatement(sql);
ps.executeUpdate();


conn.commit();
ps.close();
}


@Test
public void Getshow() throws Exception {
String url = "jdbc:mysql:///bank";
String Driverclass = "com.mysql.jdbc.Driver";
String user = "root";
String password = "123456";
Class.forName(Driverclass);
Connection conn = (Connection) DriverManager.getConnection(url, user, password);
conn.setAutoCommit(false);
String sql = "Select BALANCE FROM CUSTOMERS where id=1";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
if (rs.next()) {
Integer balance1 = rs.getInt("balance");
System.out.println(balance1);
}
conn.commit();
ps.close();
                rs.close();

}
}