一、环境搭建
1、创建数据库表
使用mybatis入门中的数据:https://blog.csdn.net/yu1755128147/article/details/103358209
2、创建maven工程并导入坐标
3、创建实体类、持久层dao接口
实体类
package com.wedu.mybatis08.domain;
import java.io.Serializable;
import java.util.Date;
/**
* 用户实体
*/
public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String sex;
private String address;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", birthday=" + birthday +
", sex='" + sex + '\'' +
", address='" + address + '\'' +
'}';
}
}
持久层接口
package com.wedu.mybatis08.dao;
import java.util.List;
/**
* 用户持久层接口
*/
public interface IUserDao {
}
4、创建数据库配置文件:jdbc.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test?useSSL=true&useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password=123456
5、创建日志文件:log4j.properties
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE debug info warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE
# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE
# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n
# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=E:\\project\\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n
6、创建配置文件:SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!--引用外部的配置文件信息-->
<properties resource="jdbc.properties"/>
<!--配置别名-->
<typeAliases>
<package name="com.wedu.mybatis08.domain"/>
</typeAliases>
<!--配置环境-->
<environments default="mysql">
<environment id="mysql">
<!--配置事务的类型-->
<transactionManager type="JDBC"></transactionManager>
<!--配置数据源-->
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</dataSource>
</environment>
</environments>
<!--配置映射文件的位置-->
<mappers>
<package name="com.wedu.mybatis08.dao" />
</mappers>
</configuration>
7、创建映射文件:IUserDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wedu.mybatis08.dao.IUserDao">
<!--抽取重复的sql语句-->
<sql id="findAllUser">
select * from user
</sql>
</mapper>
8、创建测试类
package com.wedu.mybatis08.dao;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import java.io.IOException;
/**
* mybatis的动态SQL测试
*/
public class UserDaoTest {
private SqlSession session;
private IUserDao userDao;
@Before
public void init() throws IOException {
//1、加载配置文件并创建SqlSessionFactory工厂
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("SqlMapConfig.xml"));
//2、使用工厂创建SqlSession对象
session = factory.openSession();
//3、使用SqlSession创建Dao接口的代理对象
userDao = session.getMapper(IUserDao.class);
}
@After
public void destroy(){
//释放资源
session.close();
}
}
二、动态SQL的使用
1、动态SQL之if元素
1.1、在IUserDao中添加方法
/**
* 动态SQL...if...
* @param user
* @return
*/
List<User> queryByIf(User user);
1.2、在IUserDao.xml中添加动态sql
<!--动态SQL...if...-->
<select id="queryByIf" parameterType="user" resultType="user">
<include refid="findAllUser"></include> where 1 = 1
<if test="username != null">
and username like #{username}
</if>
</select>
1.3、在测试类UserDaoTest中添加测试方法
/**
* 测试动态SQl...if...
*/
@Test
public void testQueryByIf() {
User user = new User();
user.setUsername("%王%");
List<User> users = userDao.queryByIf(user);
for (User user1 : users) {
System.out.println(user1);
}
}
2、动态SQL之choose元素
2.1、在IUserDao中添加方法
/**
* 动态SQL...choose...
* @param user
* @return
*/
List<User> queryByChoose(User user);
2.2、在IUserDao.xml中添加动态sql
<!--动态SQL...choose...-->
<select id="queryByChoose" parameterType="user" resultType="user">
<include refid="findAllUser"></include> where 1 = 1
<choose>
<when test="username != null">
and username like #{username}
</when>
<otherwise>
order by username
</otherwise>
</choose>
</select>
2.3、在测试类UserDaoTest中添加测试方法
/**
* 测试动态SQl...choose...
*/
@Test
public void testQueryByChoose() {
User user = new User();
user.setUsername("%王%");
List<User> users = userDao.queryByChoose(user);
for (User user1 : users) {
System.out.println(user1);
}
}
3、动态SQL之trim元素
3.1、在IUserDao中添加方法
/**
* 动态SQL...trim...
* @param user
* @return
*/
List<User> queryByTrim(User user);
3.2、在IUserDao.xml中添加动态sql
<!--动态SQL...trim...-->
<select id="queryByTrim" parameterType="user" resultType="user">
<include refid="findAllUser"></include>
<trim prefix="where" prefixOverrides="AND / OR">
<if test="username != null">
username like #{username}
</if>
<if test="sex != null">
and sex = #{sex}
</if>
</trim>
</select>
3.3、在测试类UserDaoTest中添加测试方法
/**
* 测试动态SQl...trim...
*/
@Test
public void testQueryByTrim() {
User user = new User();
user.setUsername("%王%");
List<User> users = userDao.queryByTrim(user);
for (User user1 : users) {
System.out.println(user1);
}
}
4、动态SQL之where元素
4.1、在IUserDao中添加方法
/**
* 动态SQL...where...
* @param user
* @return
*/
List<User> queryByWhere(User user);
4.2、在IUserDao.xml中添加动态sql
<!--动态SQL...where...-->
<select id="queryByWhere" parameterType="user" resultType="user">
<include refid="findAllUser"></include>
<where>
<if test="username != null">
username like #{username}
</if>
</where>
</select>
4.3、在测试类UserDaoTest中添加测试方法
/**
* 测试动态SQl...where...
*/
@Test
public void testQueryByWhere() {
User user = new User();
user.setUsername("%王%");
List<User> users = userDao.queryByWhere(user);
for (User user1 : users) {
System.out.println(user1);
}
}
5、动态SQL之集合操作
5.1、创建值对象QueryVo
package com.wedu.mybatis08.domain;
import java.util.List;
public class QueryVo {
private List<Integer> ids;
public List<Integer> getIds() {
return ids;
}
public void setIds(List<Integer> ids) {
this.ids = ids;
}
}
5.2、在IUserDao中添加方法
/**
* 根据queryvo中提供的id集合,查询用户信息
* @param queryVo
* @return
*/
List<User> findByQueryVo(QueryVo queryVo);
5.3、在IUserDao.xml中添加动态sql
<!--根据queryvo中提供的id集合,查询用户信息-->
<select id="findByQueryVo" parameterType="user" resultType="user">
<include refid="findAllUser"></include>
<where>
<if test="ids != null and ids.size()>0">
<foreach collection="ids" open="and id in (" close=")" item="uid" separator=",">
#{uid}
</foreach>
</if>
</where>
</select>
5.4、在测试类UserDaoTest中添加测试方法
/**
* 根据queryvo中提供的id集合,查询用户信息
*/
@Test
public void testFindByQueryVo() {
QueryVo queryVo = new QueryVo();
List<Integer> list = new ArrayList<>();
list.add(41);
list.add(42);
list.add(43);
queryVo.setIds(list);
List<User> users = userDao.findByQueryVo(queryVo);
for (User user1 : users) {
System.out.println(user1);
}
}