通过java查询数据库表结构

public static void getConnAndTableStruct() {
Connection connection = null;
PreparedStatement pstmt = null;
ResultSetMetaData rsmd = null;
try {
   // mysql连接
   //Class.forName("org.gjt.mm.mysql.Driver");
   //connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root");
   // oracle连接
    Class.forName("oracle.jdbc.driver.OracleDriver");
    String url="jdbc:oracle:thin:@192.168.12.12:1521:db";
    connection=DriverManager.getConnection(url,"manager","manager");
   pstmt = (PreparedStatement) connection.prepareStatement("select * from A_STAT");
   pstmt.execute(); // 这点特别要注意:如果是Oracle而对于mysql可以不用加.
   rsmd = (ResultSetMetaData) pstmt.getMetaData();
   //className = "User";
   //tableName = "user";
   for (int i = 1; i < rsmd.getColumnCount() + 1; i++) {
    //rsmd.getColumnName(i);
    //rsmd.getColumnClassName(i).substring(rsmd.getColumnClassName(i).lastIndexOf(".") + 1);
    System.out.println(rsmd.getColumnClassName(i));
    System.out.println(rsmd.getColumnName(i));
    System.out.println(rsmd.getColumnTypeName(i));
    System.out.println(rsmd.getPrecision(i));
    System.out.println(rsmd.getScale(i));
    System.out.println(rsmd.isNullable(i));//0 不能为空   1可以为空
    System.out.println("=============================");
    System.out.println("=============================");
    System.out.println("=============================");
    System.out.println("