// sql语句
String sql = "select a.*, b.* from table1 a, table2 b";
// 链接数据库
Connection conn = MySqlConnection.getConnection();
PreparedStatement ps = (PreparedStatement) conn
        .prepareStatement(sql, ResultSet.TYPE_SCROLL_SENSITIVE,
                ResultSet.CONCUR_READ_ONLY);
ResultSet rs = ps.executeQuery();

// 获取数据
while (rs.next()) {
    
    for (int i = 1; i <= rs.getMetaData().getColumnCount(); i++) {
        // 存放数据，以“表.字段”形式
        System.out.println(rs.getMetaData().getTableName(i) + "."
                + rs.getMetaData().getColumnLabel(i));
    }
    
}