近日做项目，表很多，不想一一写CRUD操作，所以整理了下实现方法，mybatis框架，具体配置此处不提，只说核心思想，有兴趣的欢迎一起讨论。
=================以下例子均用User为范例==============
1.实体类
public class User {
private Integer id;
private String username;
private String mobile;
//其他属性……get/set方法省略
}2.dao层（此处命名为mapper后缀）
BaseMapper.java文件，为dao层所有父类接口：
public interface BaseMapper<T,ID extends Serializable> {
int deleteByPrimaryKey(ID id);
int insert(T record);
int insertSelective(T record);
T selectByPrimaryKey(ID id);
int updateByPrimaryKeySelective(T record);
int updateByPrimaryKey(T record);
List<T> selectAll();
}参数说明：T为实现类对应类型，ID为主键类型，具体方法不再具体介绍
UserMapper.java，BaseMapper的子接口，此处添加三个新方法
public interface UserMapper extends BaseMapper<User, Integer>{
User selectByMobile(String mobile);
int updateByMobileSelective(User user);
List<User> selectStudents();
}UserMapper.xml，由插件生成，很长，但 不重要，无需细看，注意映射路径即可，不再详细说明
<?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.mingxu.mapper.UserMapper">
<resultMap id="BaseResultMap" type="com.mingxu.entity.User">
<id column="id" jdbcType="INTEGER" property="id" />
<result column="username" jdbcType="VARCHAR" property="username" />
<result column="mobile" jdbcType="VARCHAR" property="mobile" />
<result column="password" jdbcType="VARCHAR" property="password" />
<result column="head_img" jdbcType="VARCHAR" property="headImg" />
<result column="open_id" jdbcType="VARCHAR" property="openId" />
<result column="id_bind" jdbcType="CHAR" property="idBind" />
<result column="insert_time" jdbcType="TIMESTAMP" property="insertTime" />
<result column="update_time" jdbcType="TIMESTAMP" property="updateTime" />
<result column="real_name" jdbcType="VARCHAR" property="realName" />
<result column="user_role" jdbcType="CHAR" property="userRole" />
<result column="is_trained" jdbcType="CHAR" property="isTrained" />
<result column="gender" jdbcType="CHAR" property="gender" />
<result column="grade" jdbcType="VARCHAR" property="grade" />
<result column="major" jdbcType="VARCHAR" property="major" />
<result column="id_card" jdbcType="VARCHAR" property="idCard" />
<result column="email" jdbcType="VARCHAR" property="email" />
</resultMap>
<sql id="Base_Column_List">
id, username, mobile, password, head_img, open_id, id_bind, insert_time, update_time,
real_name, user_role, is_trained, gender, grade, major, id_card, email
</sql>
<select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
select
<include refid="Base_Column_List" />
from user
where id = #{id,jdbcType=INTEGER}
</select>
<delete id="deleteByPrimaryKey" parameterType="java.lang.Integer">
delete from user
where id = #{id,jdbcType=INTEGER}
</delete>
<insert id="insert" parameterType="com.mingxu.entity.User">
insert into user (id, username, mobile,
password, head_img, open_id,
id_bind, insert_time, update_time,
real_name, user_role, is_trained,
gender, grade, major,
id_card, email)
values (#{id,jdbcType=INTEGER}, #{username,jdbcType=VARCHAR}, #{mobile,jdbcType=VARCHAR},
#{password,jdbcType=VARCHAR}, #{headImg,jdbcType=VARCHAR}, #{openId,jdbcType=VARCHAR},
#{idBind,jdbcType=CHAR}, #{insertTime,jdbcType=TIMESTAMP}, #{updateTime,jdbcType=TIMESTAMP},
#{realName,jdbcType=VARCHAR}, #{userRole,jdbcType=CHAR}, #{isTrained,jdbcType=CHAR},
#{gender,jdbcType=CHAR}, #{grade,jdbcType=VARCHAR}, #{major,jdbcType=VARCHAR},
#{idCard,jdbcType=VARCHAR}, #{email,jdbcType=VARCHAR})
</insert>
<insert id="insertSelective" parameterType="com.mingxu.entity.User">
insert into user
<trim prefix="(" suffix=")" suffixOverrides=",">
<if test="id != null">
id,
</if>
<if test="username != null">
username,
</if>
<if test="mobile != null">
mobile,
</if>
<if test="password != null">
password,
</if>
<if test="headImg != null">
head_img,
</if>
<if test="openId != null">
open_id,
</if>
<if test="idBind != null">
id_bind,
</if>
<if test="insertTime != null">
insert_time,
</if>
<if test="updateTime != null">
update_time,
</if>
<if test="realName != null">
real_name,
</if>
<if test="userRole != null">
user_role,
</if>
<if test="isTrained != null">
is_trained,
</if>
<if test="gender != null">
gender,
</if>
<if test="grade != null">
grade,
</if>
<if test="major != null">
major,
</if>
<if test="idCard != null">
id_card,
</if>
<if test="email != null">
email,
</if>
</trim>
<trim prefix="values (" suffix=")" suffixOverrides=",">
<if test="id != null">
#{id,jdbcType=INTEGER},
</if>
<if test="username != null">
#{username,jdbcType=VARCHAR},
</if>
<if test="mobile != null">
#{mobile,jdbcType=VARCHAR},
</if>
<if test="password != null">
#{password,jdbcType=VARCHAR},
</if>
<if test="headImg != null">
#{headImg,jdbcType=VARCHAR},
</if>
<if test="openId != null">
#{openId,jdbcType=VARCHAR},
</if>
<if test="idBind != null">
#{idBind,jdbcType=CHAR},
</if>
<if test="insertTime != null">
#{insertTime,jdbcType=TIMESTAMP},
</if>
<if test="updateTime != null">
#{updateTime,jdbcType=TIMESTAMP},
</if>
<if test="realName != null">
#{realName,jdbcType=VARCHAR},
</if>
<if test="userRole != null">
#{userRole,jdbcType=CHAR},
</if>
<if test="isTrained != null">
#{isTrained,jdbcType=CHAR},
</if>
<if test="gender != null">
#{gender,jdbcType=CHAR},
</if>
<if test="grade != null">
#{grade,jdbcType=VARCHAR},
</if>
<if test="major != null">
#{major,jdbcType=VARCHAR},
</if>
<if test="idCard != null">
#{idCard,jdbcType=VARCHAR},
</if>
<if test="email != null">
#{email,jdbcType=VARCHAR},
</if>
</trim>
</insert>
<update id="updateByPrimaryKeySelective" parameterType="com.mingxu.entity.User">
update user
<set>
<if test="username != null">
username = #{username,jdbcType=VARCHAR},
</if>
<if test="mobile != null">
mobile = #{mobile,jdbcType=VARCHAR},
</if>
<if test="password != null">
password = #{password,jdbcType=VARCHAR},
</if>
<if test="headImg != null">
head_img = #{headImg,jdbcType=VARCHAR},
</if>
<if test="openId != null">
open_id = #{openId,jdbcType=VARCHAR},
</if>
<if test="idBind != null">
id_bind = #{idBind,jdbcType=CHAR},
</if>
<if test="insertTime != null">
insert_time = #{insertTime,jdbcType=TIMESTAMP},
</if>
<if test="updateTime != null">
update_time = #{updateTime,jdbcType=TIMESTAMP},
</if>
<if test="realName != null">
real_name = #{realName,jdbcType=VARCHAR},
</if>
<if test="userRole != null">
user_role = #{userRole,jdbcType=CHAR},
</if>
<if test="isTrained != null">
is_trained = #{isTrained,jdbcType=CHAR},
</if>
<if test="gender != null">
gender = #{gender,jdbcType=CHAR},
</if>
<if test="grade != null">
grade = #{grade,jdbcType=VARCHAR},
</if>
<if test="major != null">
major = #{major,jdbcType=VARCHAR},
</if>
<if test="idCard != null">
id_card = #{idCard,jdbcType=VARCHAR},
</if>
<if test="email != null">
email = #{email,jdbcType=VARCHAR},
</if>
</set>
where id = #{id,jdbcType=INTEGER}
</update>
<update id="updateByPrimaryKey" parameterType="com.mingxu.entity.User">
update user
set username = #{username,jdbcType=VARCHAR},
mobile = #{mobile,jdbcType=VARCHAR},
password = #{password,jdbcType=VARCHAR},
head_img = #{headImg,jdbcType=VARCHAR},
open_id = #{openId,jdbcType=VARCHAR},
id_bind = #{idBind,jdbcType=CHAR},
insert_time = #{insertTime,jdbcType=TIMESTAMP},
update_time = #{updateTime,jdbcType=TIMESTAMP},
real_name = #{realName,jdbcType=VARCHAR},
user_role = #{userRole,jdbcType=CHAR},
is_trained = #{isTrained,jdbcType=CHAR},
gender = #{gender,jdbcType=CHAR},
grade = #{grade,jdbcType=VARCHAR},
major = #{major,jdbcType=VARCHAR},
id_card = #{idCard,jdbcType=VARCHAR},
email = #{email,jdbcType=VARCHAR}
where id = #{id,jdbcType=INTEGER}
</update>
<select id="selectByMobile" parameterType="String" resultMap="BaseResultMap">
select
<include refid="Base_Column_List" />
from user
where mobile = #{mobile,jdbcType=VARCHAR}
</select>
<update id="updateByMobileSelective" parameterType="com.mingxu.entity.User">
update user
<set>
<if test="username != null">
username = #{username,jdbcType=VARCHAR},
</if>
<if test="password != null">
password = #{password,jdbcType=VARCHAR},
</if>
<if test="headImg != null">
head_img = #{headImg,jdbcType=VARCHAR},
</if>
<if test="openId != null">
open_id = #{openId,jdbcType=VARCHAR},
</if>
<if test="idBind != null">
id_bind = #{idBind,jdbcType=CHAR},
</if>
<if test="insertTime != null">
insert_time = #{insertTime,jdbcType=TIMESTAMP},
</if>
<if test="updateTime != null">
update_time = #{updateTime,jdbcType=TIMESTAMP},
</if>
<if test="realName != null">
real_name = #{realName,jdbcType=VARCHAR},
</if>
<if test="userRole != null">
user_role = #{userRole,jdbcType=CHAR},
</if>
<if test="isTrained != null">
is_trained = #{isTrained,jdbcType=CHAR},
</if>
<if test="gender != null">
gender = #{gender,jdbcType=CHAR},
</if>
<if test="grade != null">
grade = #{grade,jdbcType=VARCHAR},
</if>
<if test="major != null">
major = #{major,jdbcType=VARCHAR},
</if>
<if test="idCard != null">
id_card = #{idCard,jdbcType=VARCHAR},
</if>
<if test="email != null">
email = #{email,jdbcType=VARCHAR},
</if>
</set>
where mobile = #{mobile,jdbcType=VARCHAR}
</update>
<select id="selectStudents" parameterType="String" resultMap="BaseResultMap">
select
<include refid="Base_Column_List" />
from user
where user_role='1' and is_trained='1'
ORDER BY insert_time DESC
</select>
</mapper>3.service层
3.1接口定义
BaseService.java，此处与dao层统一
public interface BaseService<T,ID extends Serializable> {
boolean removeByPrimaryKey(ID id);
boolean add(T record);
boolean addSelective(T record);
T findByPrimaryKey(ID id);
boolean saveByPrimaryKeySelective(T record);
boolean saveByPrimaryKey(T record);
List<T> findAll();
}public interface UserService extends BaseService<Dept, Integer> {
}BaseServiceImpl.java这个类很重要，是数据库操作的实现
@Service
public abstract class BaseServiceImpl<T, ID extends Serializable> implements BaseService<T, ID> {
public abstract BaseMapper<T, ID> getMapper();
@Override
public boolean removeByPrimaryKey(ID id) {
return getMapper().deleteByPrimaryKey(id) > 0;
}
@Override
public boolean add(T record) {
return getMapper().insert(record) > 0;
}
@Override
public boolean addSelective(T record) {
return getMapper().insertSelective(record) > 0;
}
@Override
public T findByPrimaryKey(ID id) {
return getMapper().selectByPrimaryKey(id);
}
@Override
public boolean saveByPrimaryKeySelective(T record) {
return getMapper().updateByPrimaryKeySelective(record) > 0;
}
@Override
public boolean saveByPrimaryKey(T record) {
return getMapper().updateByPrimaryKey(record) > 0;
}
@Override
public List<T> findAll() {
return getMapper().selectAll();
}
}@Service
public class UserServiceImpl extends BaseServiceImpl<Archives, Integer> implements ArchivesService{
@Resource
private UserMapper mapper;
@Override
public BaseMapper<Archives, Integer> getMapper() {
return mapper;
}
}版权声明：本文为jinxiguo原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接和本声明。