getGeneratedKeys自动获取主键的方法

1. public class Demo
   {
   
   public static void main(String[] args) {
   
   try {
   String sql="insert into person values(?,?)";
   Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
   Connection conn=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databaseName=pubs","sa","");
   
   //需要增加一个Statement.RETURN_GENERATED_KEYS这样的参数
   java.sql.PreparedStatement p=conn.PreparedStatement(sql,Statement.RETURN_GENERATED_KEYS);
   p.setObject(1, "zengguofeef");
   
   //p.setObject(2, new java.sql.Date(System.currentTimeMillis()));
   
   //必须这样设置,System.currentTimeMillis()表示当前系统时间的毫秒数,Timestamp()方法会根据这个毫秒数设置成当前时间
   p.setTimestamp(2, new java.sql.Timestamp(System.currentTimeMillis()));
   p.executeUpdate();
   
   
   //通过这个方法获取getGeneratedKeys();
   ResultSet rs=p.getGeneratedKeys();
   rs.next();
   int num=rs.getInt(1);
   System.out.println("自动增长列为:"+num);
   } catch (ClassNotFoundException e) {
   e.printStackTrace();
   } catch (SQLException e) {
   e.printStackTrace();
   }
   }
   
   
   
   public static void main(String[] args)
   {
   
   //在sql语句后面加上一个select scope_identity()
   String sql="insert into person values(?,?) select scope_identity()";
   try {
   Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
   Connection conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;databaseName=pubs","sa","");
   java.sql.PreparedStatement p=conn.prepareStatement(sql);
   p.setObject(1, "zengguofeef");
   p.setTimestamp(2, new java.sql.Timestamp(System.currentTimeMillis()));
   //这里使用的是executeQuery()方法,而不是executeUpdate()
   ResultSet rs=p.executeQuery();
   rs.next();
   int num=rs.getInt(1);
   System.out.println("自动增长列为:"+num);
   conn.close();
   } catch (ClassNotFoundException e) {
   e.printStackTrace();
   } catch (SQLException e) {
   e.printStackTrace();
   }
   }
   }