//功能为单独表的查询。
//报错为：（查询其余正确，在查询Date时报下面错误）
public Stuinjava.lang.IllegalArgumentException: [b]Can not set java.util.Date field jdbc.bean.Stuinfo.birth to java.lang.String fo queryForStuinfo(String sql,Object...args) {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            //1.获取数据库的连接
            conn = JDBCUtils.getConnection();
            //2.预编译sql语句并返回preparedStatement的实例
            ps = conn.prepareStatement(sql);
            for (int i = 0; i <args.length; i++) {
                ps.setObject(i+1,args[i]);
            }
            rs = ps.executeQuery();
            //获取结果集的元数据：ResultSetMetaDa();
            ResultSetMetaData rsmd = rs.getMetaData();
            //通过ResultSetMeData获取结果集中的列数
            int columnCount = rsmd.getColumnCount();
            if(rs.next()){
                Stuinfo stuinfo = new Stuinfo();
                //处理结果集一行数据中的每一个列
                for (int i = 0; i <columnCount ; i++) {
                    //获取列值
                    Object columValue = rs.getObject(i + 1);
                    //获取每个列的列名
                    String columnName = rsmd.getColumnName(i+1);
                    //给stuinfo对象指定的columnName属性：赋值为columnValue通过反射
                    Field declaredField = Stuinfo.class.getDeclaredField(columnName);
                    declaredField.setAccessible(true);
                    declaredField.set(stuinfo,columValue);
                }
                return stuinfo;
            }
        } catch (Exception e){
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(conn,ps,rs);
        }
        return null;
    }

灵光乍现，应该把mysql中的数据类型由varchar改为data。哈哈哈哈哈哈