Mybatis处理枚举类型

1、枚举

package com.ahut.core.enums;

import java.util.HashMap;
import java.util.Map;

/**
 * 
 * @ClassName: SexEnum
 * @Description: 性别枚举
 * @author cheng
 * @date
public enum SexEnum {

    MAN("1", "男"), WOMAN("2", "女");

    private String key;
    private String value;
    private static Map<String, SexEnum> sexEnumMap = new HashMap<>();

    static {
        for (SexEnum sexEnum : SexEnum.values()) {
            sexEnumMap.put(sexEnum.getKey(), sexEnum);
        }
    }

    /**
     * 私有化构造函数
     * 
     * @param key
     * @param
    private SexEnum(String key, String value) {
        this.key = key;
        this.value = value;
    }

    /**
     * 
     * @Title: getSexEnumByKey
     * @Description: 依据key获取枚举
     * @param key
     * @return
    public static SexEnum getSexEnumByKey(String key) {
        return sexEnumMap.get(key);
    }

    public String getKey() {
        return key;
    }

    public void setKey(String key) {
        this.key = key;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

}

2、包含枚举的实体类

package com.ahut.entity;

import java.io.Serializable;
import java.util.Date;

import com.ahut.core.enums.SexEnum;

/**
 * 
 * @ClassName: Demo
 * @Description:
 * @author cheng
 * @date
public class Demo implements Serializable

    /**
     * 
     */
    private static final long serialVersionUID = 4122974131420281791L;

    private Date birthDay;
    private String userName;
    private int age;
    private String id;
    private SexEnum sex;

    public Demo() {
        super();
        // TODO Auto-generated constructor stub
    }

    @Override
    public String toString() {
        return "Demo [id=" + id + ", userName=" + userName + ", age=" + age + ", birthDay=" + birthDay + ", sex=" + sex
                + "]";
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Date getBirthDay() {
        return birthDay;
    }

    public void setBirthDay(Date birthDay) {
        this.birthDay = birthDay;
    }

    public SexEnum getSex() {
        return sex;
    }

    public void setSex(SexEnum sex) {
        this.sex = sex;
    }

}

3、书写枚举处理器

package com.ahut.handler;

import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;

import com.ahut.core.enums.SexEnum;

/**
 * 
 * @ClassName: EnumHandler
 * @Description:
 * @author cheng
 * @date
public class SexEnumHandler extends BaseTypeHandler<SexEnum> {

    /**
     * 用于定义设置参数时，该如何把Java类型的参数转换为对应的数据库类型
     */
    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, SexEnum parameter, JdbcType jdbcType)
            throws SQLException {
        // baseTypeHandler已经帮我们做了parameter的null判断
        // 第二个参数 : 存入到数据库中的值
        ps.setString(i, parameter.getKey());
    }

    /**
     * 用于定义通过字段名称获取字段数据时，如何把数据库类型转换为对应的Java类型
     */
    @Override
    public SexEnum getNullableResult(ResultSet rs, String columnName) throws SQLException {

        System.out.println("columnName执行我");

        // 根据数据库存储类型决定获取类型，本例子中数据库中存放String类型
        String key = rs.getString(columnName);
        if (rs.wasNull()) {
            return null;
        } else {
            // 根据数据库中的key值，定位SexEnum子类
            return SexEnum.getSexEnumByKey(key);
        }
    }

    /**
     * 用于定义通过字段索引获取字段数据时，如何把数据库类型转换为对应的Java类型
     */
    @Override
    public SexEnum getNullableResult(ResultSet rs, int columnIndex) throws SQLException {

        System.out.println("columnIndex执行我");

        // 根据数据库存储类型决定获取类型，本例子中数据库中存放String类型
        String key = rs.getString(columnIndex);
        if (rs.wasNull()) {
            return null;
        } else {
            // 根据数据库中的key值，定位SexEnum子类
            return SexEnum.getSexEnumByKey(key);
        }
    }

    /**
     * 用定义调用存储过程后，如何把数据库类型转换为对应的Java类型
     */
    @Override
    public SexEnum getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        // 根据数据库存储类型决定获取类型，本例子中数据库中存放String类型
        String key = cs.getString(columnIndex);
        if (cs.wasNull()) {
            return null;
        } else {
            // 根据数据库中的key值，定位SexEnum子类
            return

4、配置枚举处理器

mybatis配置

<?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>
    <settings>
        <!-- 打印sql语句 -->
        <setting name="logImpl" value="STDOUT_LOGGING"
    </settings>
    <typeHandlers>
        <typeHandler handler="com.ahut.handler.SexEnumHandler"
            javaType="com.ahut.core.enums.SexEnum" jdbcType="CHAR"
    </typeHandlers>
</configuration>

5、dao层

package com.ahut.mapper;

import java.util.List;
import java.util.Map;

import com.ahut.entity.Demo;

/**
 * 
 * @ClassName: DemoMapper
 * @Description:
 * @author cheng
 * @date
public interface DemoMapper

    /**
     * 
     * @Title: saveDemo
     * @Description: 保存
     * @param map
     * @throws
    void saveDemo(Map<String, Object> map) throws Exception;

    /**
     * 
     * @Title: selectDemoList
     * @Description: 查询
     * @return
     * @throws
    List<Map<String, Object>> selectDemoList() throws Exception;

    /**
     * 
     * @Title: selectDemoList1
     * @Description: 查询
     * @return
     * @throws
    List<Demo> selectDemoList1() throws

6、mapper文件

<?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.ahut.mapper.DemoMapper">

    <!-- 保存 -->
    <insert id="saveDemo" parameterType="map">
        INSERT INTO DEMO
        VALUES(replace(UUID(),'-',''),#{USER_NAME},#{AGE},#{BIRTH_DAY},#{SEX})
    </insert>

    <!-- 查询 -->
    <select id="selectDemoList" resultType="map">
        SELECT
        ID,
        USER_NAME,
        AGE,
        BIRTH_DAY,
        SEX
        FROM DEMO
    </select>

    <!-- 查询 -->
    <select id="selectDemoList1" resultType="com.ahut.entity.Demo">
        SELECT
        ID,
        USER_NAME USERNAME,
        AGE,
        BIRTH_DAY BIRTHDAY,
        SEX
        FROM DEMO
    </select>

</mapper>

7、测试

package com.ahut.service;

import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import com.ahut.core.enums.SexEnum;
import com.ahut.entity.Demo;

/**
 * 
 * @ClassName: DemoServiceTest
 * @Description:
 * @author cheng
 * @date
@SpringBootTest
@RunWith(SpringRunner.class)
public class DemoServiceTest

    @Autowired
    private DemoService demoService;

    /**
     * 
     * @Title: testSelectDemoList1
     * @Description:
     * @throws
    @Test
    public void testSelectDemoList1() throws Exception {
        List<Demo> demoList = demoService.selectDemoList1();
        for (Demo demo : demoList) {
            System.out.println(demo);
        }
    }

    /**
     * 
     * @Title: testSelectDemoList
     * @Description:
     * @throws
    @Test
    public void testSelectDemoList() throws Exception {
        List<Map<String, Object>> demoList = demoService.selectDemoList();
        for (Map<String, Object> map : demoList) {
            for (String key : map.keySet()) {
                if (key.equals("BIRTH_DAY")) {
                    Date birthDay = (Date) map.get(key);
                    System.out.println(key + ":" + birthDay);
                } else if (key.equals("AGE")) {
                    int age = (int) map.get(key);
                    System.out.println(key + ":" + age);
                } else if (key.equals("SEX")) {
                    SexEnum sex = (SexEnum) map.get(key);
                    System.out.println(key + ":" + sex);
                } else {
                    String value = (String) map.get(key);
                    System.out.println(key + ":" + value);
                }
            }
        }
    }

    /**
     * 
     * @Title: testSaveDemo
     * @Description:
     * @throws
    @Test
    public void testSaveDemo() throws Exception {
        Map<String, Object> map = new HashMap<>();
        map.put("USER_NAME", "rick11");
        map.put("AGE", 22);
        map.put("BIRTH_DAY", new Date());
        map.put("SEX", SexEnum.WOMAN);
        demoService.saveDemo(map);
    }

}

执行testSaveDemo方法：

SexEnum.WOMAN被转换成了2存入到数据库中

执行testSelectDemoList1方法：

数据库中的1、2成功被转换成了枚举

当resultType为包含枚举的实体类时，mybatis调用了枚举处理器

执行testSelectDemoList方法：

报错

由下图可知，resultType为map时，并没有调用枚举处理器