if-else 及if嵌套使用方式
案例一：if-else
在使用mybatis mapper 动态sql时，不免会出现if-else的使用，但是好像又没有这种语法，提供的是choose标签代替if-else
例如：
|
1 2 3 4 5 6 7 8 9 10 11 12 |
select * from t_stu t < where > <choose> < when test= "query == 0" > and t.status = 1 </ when > <otherwise> and t.status NOT IN (9,5) </otherwise> </choose> and t.delete_status = 1 </ where > |
也可以用多个if判断实现：
|
1 2 3 4 5 6 7 8 9 10 |
select * from t_stu t < where > <if test= "query == 0" > and t.status = 1 </if> <if test= "query != 0" > and t.status NOT IN (9,5) </if> and t.delete_status = 1 </ where > |
案例二：if嵌套
在实际编码过程中会有一些判断条件会一直重复使用，一直写在if标签中写的代码会特长，而且臃肿
|
1 2 3 4 5 6 7 8 9 10 11 12 |
select * from t_stu t < where > <if test= "query == 0 and type = 1" > and t.type = 'we' and t. delete = 1 </if> <if test= "query == 0 and type = 2" > and t.type = 'wq' and t. delete = 1 </if> <if test= "query == 0 and type = 3" > and t.type = 'wr' and t. delete = 1 </if> </ where > |
变现后：
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
select * from t_stu t < where > <if test= "query == 0" > <if test= "type = 1" > and t.type = 'we' </if> <if test= "type = 2" > and t.type = 'wq' </if> <if test= "type = 3" > and t.type = 'wr' </if> </if> and t. delete = 1 </ where > |
mybatis if-else写法
mybaits中没有else要用chose when otherwise代替
|
1 2 3 4 5 6 7 8 |
<choose> < when test= "" > //... </ when > <otherwise> //... </otherwise> </choose> |
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
原文链接：https://blog.csdn.net/qq_43040552/article/details/104747240
查看更多关于mybatis中的if-else及if嵌套使用方式的详细内容...