[jeeplus] 使用笔记 (gridSelect、datetimepicker etc.)

命名不规范，码农两行泪!!!😭
自己把自己坑哭

java 中 字符串的 slipt() 方法

1. slipt() 方法会在分割完成后，对获取到的数组从末端开始验证是否为""，若 true 则，数组长度 -1 ，直到遇到一个不为"" 的元素。
2. 此时，在这个不为 "" 的元素之前的所有其他 "" 元素依旧保留。（未验证数组起始端的 "" 是否验证排除）
3. 不知道从 1.5 开始到现在最新版本，该方法是否发生变化。

    public static void main(String[] args) {

	String s = "";
	String[] ss =  s.split(",");
        System.out.println(ss.length);//1
        System.out.println(Arrays.toString(ss));//[]
        System.out.println(ss == null);//false
        System.out.println(ss[0] == null);//false

        String s1 = "123-123.2-1--";
        String[] ss1 =  s1.split("-");
        System.out.println(ss1.length);//3
        System.out.println(Arrays.toString(ss1));//[123, 123.2, 1]

        String s2 = "123--123.2-1--";
        String[] ss2 =  s2.split("-");
        System.out.println(ss2.length);//4
        System.out.println(Arrays.toString(ss2));//[123, , 123.2, 1]
    }
​

参考 ：
https://blog.csdn.net/qq_27093465/article/details/54910323

MySql 中根据 判断某个字段（字符串）的长度后 按不同情况更新 同一个字段的值 的方法：

UPDATE m_levelformajor 

SET type = (
	CASE
		WHEN 1 < LENGTH(number) AND  LENGTH(number) < 3 THEN "2"
		WHEN 3 < LENGTH(number) AND  LENGTH(number) < 5 THEN "3"
		WHEN 6 <= LENGTH(number) THEN "4"
		WHEN number IS NULL THEN "1"
	ELSE
		"1"
	END
)

UPDATE m_levelformajor 
SET type = (
	CASE

		WHEN number IS NULL THEN "1"
	ELSE
		 "1"
	END
)

SELECT id,name, number, type, parent_id,parent_ids , LENGTH(number) FROM m_levelformajor
SELECT id,name, number, type, parent_id,parent_ids , LENGTH(number) FROM m_levelformajor WHERE  LENGTH(number) <5 AND  LENGTH(number) > 3
SELECT id,name, number, type, parent_id,parent_ids , LENGTH(number) FROM m_levelformajor WHERE  1 < LENGTH(number)  AND  LENGTH(number) <3
SELECT id,name, number, type, parent_id,parent_ids , LENGTH(number) FROM m_levelformajor WHERE   LENGTH(number) <1``` 
​

根据某列中的值是否包含某个字符串筛选记录：

UPDATE m_levelformajor 
SET type = (
	CASE
		WHEN 1 < LENGTH(number) AND  LENGTH(number) < 3 THEN "22"
		WHEN 3 < LENGTH(number) AND  LENGTH(number) < 5 THEN "23"
		WHEN 6 <= LENGTH(number) THEN "24"
		WHEN number IS NULL THEN "21"
	ELSE
		"1"
	END
)
WHERE find_in_set('19db900b7129468385d96f96cd6c672a', parent_ids);

--设置本科专业记录的 type
UPDATE m_levelformajor 
SET type = (
	CASE
		WHEN 1 < LENGTH(number) AND  LENGTH(number) < 3 THEN "12"
		WHEN 3 < LENGTH(number) AND  LENGTH(number) < 5 THEN "13"
		WHEN 6 <= LENGTH(number) THEN "14"
		WHEN number IS NULL THEN "11"
	ELSE
		"1"
	END
)
WHERE find_in_set('e131fdeaf3f041b086bec4e68dd096c7', parent_ids);``` 
​