MyBatis内部提供了两个转化枚举类型的typeHandler给我们使用。
- org.apache.ibatis.type.EnumTypeHandler 是使用枚举字符串名称作为参数传递的
- org.apache.ibatis.type.EnumOrdinalTypeHandler 是使用整数下标作为参数传递的
数据库脚CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT, `userName` varchar(50) DEFAULT NULL, `gender` int(11) DEFAULT NULL, --对应Gender枚举类 `hobby` varchar(255) DEFAULT NULL, --对用Hobby枚举类
`member` int(11) DEFAULT NULL, --对应Member枚举类
`userAge` int(11) DEFAULT NULL, `userAddress` varchar(200) DEFAULT NULL, `reg_time` varchar(200) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;
创建三个枚举类Gender、Hobby、Member
package com.yihaomen.mybatis.enums; public enum Gender { MALE(1, "男性"), FEMALE(2, "女性"); private int code; private String name; Gender(int code, String name) { this.code = code; this.name = name; } public int getCode() { return code; } public void setCode(int code) { this.code = code; } public String getName() { return name; } public void setName(String name) { this.name = name; } public static Gender getGender(int code) { for(Gender gender : Gender.values()) { if(gender.getCode() == code) { return gender; } } return null; } }
package com.yihaomen.mybatis.enums; public enum Hobby { FOOTBALL(1,"足球"), BASKETBALL(2, "篮球"); private int code; private String name; Hobby(int code, String name) { this.code = code; this.name = name; } public int getCode() { return code; } public void setCode(int code) { this.code = code; } public String getName() { return name; } public static Hobby getHobby(int code) { for(Hobby h : Hobby.values()) { if(h.getCode() == code) { return h; } } return null; } public void setName(String name) { this.name = name; } }
package com.yihaomen.mybatis.enums; public enum Member { FATHER(1,"爸爸"), MOTHER(2,"妈妈"); private int code; private String name; Member(int code, String name) { this.code = code; this.name = name; } public int getCode() { return code; } public void setCode(int code) { this.code = code; } public String getName() { return name; } public void setName(String name) { this.name = name; } public static Member getMember(int code) { for(Member member : Member.values()) { if(member.getCode() == code) { return member; } } return null; } }
写model层
package com.yihaomen.mybatis.model; import com.yihaomen.mybatis.enums.Gender; import com.yihaomen.mybatis.enums.Hobby; import java.util.Date; public class User { private int id; private String userName; private String userAge; private Gender gender;
private Member member; private Hobby hobby; private String userAddress; private Date regTime; setters()&getters()... }
自定义typeHandler
package com.yihaomen.mybatis.type;
import com.yihaomen.mybatis.enums.Member;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.TypeHandler;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class MyMemberTypeHandler implements TypeHandler<Member> {
public void setParameter(PreparedStatement ps, int i, Member parameter, JdbcType jdbcType) throws SQLException {
ps.setInt(i, parameter.getCode());
}
public Member getResult(ResultSet rs, String columnName) throws SQLException {
int code = rs.getInt(columnName);
return Member.getMember(code);
}
public Member getResult(ResultSet rs, int columnIndex) throws SQLException {
int code = rs.getInt(columnIndex);
return Member.getMember(code);
}
public Member getResult(CallableStatement cs, int columnIndex) throws SQLException {
int code = cs.getInt(columnIndex);
return Member.getMember(code);
}
}
写DAO层
User.xml
<?xml version="1.0" encoding="UTF-8" ?> <resultMap id="resultListUser" type="User"> <id column="id" property="id" /> <result column="userName" property="userName" /> <result column="userAge" property="userAge" />
<!----> <result column="gender" property="gender" typeHandler="org.apache.ibatis.type.EnumOrdinalTypeHandler"/> <result column="hobby" property="hobby" typeHandler="org.apache.ibatis.type.EnumTypeHandler"/>
<result column="member" property="member" typeHandler="com.yihaomen.mybatis.type.MyMemberTypeHandler"/><!--自定义枚举typeHandler-->
<result column="userAddress" property="userAddress" /> <result column="reg_time" property="regTime" javaType="java.util.Date" jdbcType="VARCHAR" typeHandler="com.yihaomen.mybatis.type.MyDateTypeHandler"/> </resultMap> <select id="selectUserById2" parameterType="long" resultMap="resultListUser"> select userName, gender, hobby from user where id = #{id}</select> <insert id="addUser2" parameterType="User" useGeneratedKeys="true" keyProperty="id"> INSERT INTO user(userName, userAge, gender, hobby, userAddress, reg_time) VALUES(#{userName},#{userAge},#{gender},#{hobby},#{userAddress}, #{regTime,javaType=Date,jdbcType=VARCHAR,typeHandler=com.yihaomen.mybatis.type.MyDateTypeHandler}) </insert>
UserMapper
package com.yihaomen.mybatis.dao; import com.yihaomen.mybatis.model.User; import org.apache.ibatis.annotations.Param; import org.springframework.stereotype.Repository; import java.util.List; @Repository public interface UserMapper { public List<User> selectUserById2(Long id); public int addUser2(User user); }
在configuration.xml注册typeHandler
<typeHandlers> <typeHandler handler="com.yihaomen.mybatis.type.MyDateTypeHandler" /> <typeHandler handler="org.apache.ibatis.type.EnumOrdinalTypeHandler" javaType="com.yihaomen.mybatis.enums.Gender" /> <typeHandler handler="org.apache.ibatis.type.EnumTypeHandler" javaType="com.yihaomen.mybatis.enums.Hobby"/>
<typeHandler handler="com.yihaomen.mybatis.type.MyMemberTypeHandler"
javaType="com.yihaomen.mybatis.enums.Member"/>
</typeHandlers>
测试一下：
package user;
import com.yihaomen.mybatis.dao.UserMapper;
import com.yihaomen.mybatis.enums.Gender;
import com.yihaomen.mybatis.enums.Hobby;
import com.yihaomen.mybatis.enums.Member;
import com.yihaomen.mybatis.model.User;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import java.util.Date;
import java.util.List;
/**
*
* @ProjectName: springmvc-mybatis
* @Description:
*/
public class TestEnumUser extends BaseTest{
public static void main(String[] args) {
// testAddEnum();
testGetEnumUser();
}
/**
* 添加
*/
public static void testAddEnum() {
SqlSession sqlSession = null;
try {
SqlSessionFactory sqlSessionFactory = getSession();
sqlSession = sqlSessionFactory.openSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
User user = new User();
user.setUserName("小明");
user.setGender(Gender.MALE);
user.setHobby(Hobby.FOOTBALL);
user.setMember(Member.FATHER);
user.setRegTime(new Date());
user.setUserAddress("地球");
user.setUserAge("22");
int result = mapper.addUser2(user);
System.out.println(result);
sqlSession.commit();
} catch (Exception e) {
e.printStackTrace();
sqlSession.rollback();
} finally {
if(sqlSession != null) {
sqlSession.close();
}
}
}
/**
* select
*/
public static void testGetEnumUser() {
SqlSession sqlSession = null;
try {
SqlSessionFactory sqlSessionFactory = getSession();
sqlSession = sqlSessionFactory.openSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
List<User> users = mapper.selectUserById2(11L);
for(User u : users) {
System.out.println(u.getGender());
System.out.println(u.getHobby());
System.out.println(u.getMember());
}
sqlSession.commit();
} catch (Exception e) {
e.printStackTrace();
sqlSession.rollback();
} finally {
if(sqlSession != null) {
sqlSession.close();
}
}
}
}
https://gitee.com/huayicompany/springmvc-mybatis.git
参考文献:
[1] 杨开振 著，《深入浅出MyBatis技术原理与实战》， 电子工业出版社，2016.09