public void delete(T entity) throws Exception{
        String sql = "delete from " + entity.getClass().getSimpleName().toLowerCase() + " where ";

        //存放字符串为"id"的字段对象
        Method idMethod = null;

        //取得字符串为"id"的字段对象
        List<Method> list = this.matchPojoMethods(entity, "get");
        Iterator<Method> iter = list.iterator();
        while(iter.hasNext()) {
            Method tempMethod = iter.next();
            //如果方法名中带有ID字符串并且长度为2,则视为ID.
            if(tempMethod.getName().lastIndexOf("Id") != -1 && tempMethod.getName().substring(3).length() == 2) {
                //把ID字段的对象存放到一个变量中,然后在集合中删掉.
                idMethod = tempMethod;
                iter.remove();
                //如果方法名去掉set/get字符串以后与pojo + "id"想符合(大小写不敏感),则视为ID
            } else if((entity.getClass().getSimpleName() + "Id").equalsIgnoreCase(tempMethod.getName().substring(3))) {
                idMethod = tempMethod;
                iter.remove();
            }
        }

        sql += idMethod.getName().substring(3).toLowerCase() + " = ?";

        PreparedStatement statement = this.connection.prepareStatement(sql);

        //为Id字段添加值
        int i = 0;
        if(idMethod.getReturnType().getSimpleName().indexOf("String") != -1) {
            statement.setString(++i, this.getString(idMethod, entity));
        } else {
            statement.setInt(++i, this.getInt(idMethod, entity));
        }

        //执行
        conn.execOther(statement);
        //关闭连接
        conn.closeConn();
    }