Java SSM架構之MyBatis3（八）MyBatis之動態SQL

標籤：ima   prefix   動態   username   去除   isp   insert   XML   建立   

前言：

　　mybatis架構中最具特色的便是sql語句中的自訂，而動態sql的使用又使整個架構更加靈活。

建立User表

/*Table structure for table `user` */DROP TABLE IF EXISTS `user`;CREATE TABLE `user` (  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,  `name` varchar(20) NOT NULL,  `username` varchar(20) NOT NULL,  `age` int(3) NOT NULL,  `phone` varchar(11) NOT NULL,  `email` varchar(50) NOT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;/*Data for the table `user` */insert  into `user`(`id`,`name`,`username`,`age`,`phone`,`email`) values (1,‘張三‘,‘zs‘,18,‘15010998046‘,‘[email protected]‘),(2,‘李四‘,‘ls‘,19,‘15019087600‘,‘[email protected]‘),(3,‘王五‘,‘ww‘,20,‘15010898065‘,‘[email protected]‘);/*!40101 SET [email protected]_SQL_MODE */;/*!40014 SET [email protected]_FOREIGN_KEY_CHECKS */;/*!40014 SET [email protected]_UNIQUE_CHECKS */;/*!40111 SET [email protected]_SQL_NOTES */;

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if標籤

User實體

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UserMapper

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UserMapper.xml

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UserController

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測試

http://localhost:8080/getUser

where標籤

<select id="getUser" resultType="cn.cnki.ref.pojo.User">        select * from user        <where>            <if test="id != null">and id=#{id} </if>            <if test="age != null">and age=#{age} </if>            <if test="name != null">and name=#{name}</if>        </where>    </select>

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trim標籤下的四個屬性：

prefix：在標籤開始添加上該字串

suffixOverrides：在標籤末尾去除上該字串

suffix：在標籤末尾添加上該字串

prefixOverrides：在標籤開始去除上該字串

set標籤

 

trim標籤

 

switch\when標籤

 

foreach標籤

 

Java SSM架構之MyBatis3（八）MyBatis之動態SQL