【spring boot】14.spring boot集成mybatis,注解方式OR映射文件方式AND pagehelper分页插件【Mybatis】pagehelper分页插件分页查询无效解决方法

spring boot集成mybatis,集成使用mybatis拖沓了好久，今天终于可以补起来了。

本篇源码中,同时使用了Spring data JPA 和 Mybatis两种方式.

在使用的过程中一定要注意,JPA和Mybatis可以在同一个方法中调用,但是如果要保证事务一致性,千万不要把JPA的操作和Mybatis的操作放在一个事务中

项目GitHub地址：GitHub地址

spring boot 2.0

==================================================================

注意点：

　　1.mybatis是有自动生成实体、Mapper映射类[实际是接口]、Mapper.xml映射文件的插件，插件名字叫【mybatis generator】，这里没有使用。

　　2.使用mybatis的话，是有两种实现方式的。

　　　　1》注解的方式

　　　　2》映射文件的方式

　　其实，注解的方式类似于JPA 的使用注解@Query()的方式。

　　整个使用下来，还是建议简单的CRUD操作，使用spring-data-JPA进行操作可以节省大量的代码量。

　　复杂的查询操作，就可以采用mybatis来完成，通过自己写sql语句提高灵活性，当然使用JPA来操作也可以完成。

　　3.第二点中的注解和映射文件两种方式 可以一起使用。

==================================================================

下面，分【注解方式】和【映射文件方式】两个大模块进行展示，并

1.pom.xml文件

除了spring boot项目的默认配置之外，再加上mysql的jar和mybatis的jar即可【这里先把mybatis的分页插件pagehelper的jar包加上，留在最后说】【使用这个分页jar包，会导致分页无效，至少在spring boot2.0是无效的】

<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
<!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
<!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper mybatis分页插件-->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>5.1.4</version>
        </dependency>

pagehelper分页插件分页查询无效解决方法

修改之后采用的分页jar包【有效的分页】

<!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper-spring-boot-starter mybatis分页插件-->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.5</version>
        </dependency>

2.application.properties配置

server.port=9666

#datasource
spring.datasource.continue-on-error=false
spring.datasource.url=jdbc:mysql://localhost:3306/swapping?useSSL=false&useUnicode=true&characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

#mybatis相关配置
#mybatis映射文件的位置
mybatis.mapper-locations=classpath:mapper/*.xml
#mybatis指定entity位置
mybatis.type-aliases-package=com.sxd.swapping.domain
#mybatis展示sql语句执行
logging.level.com.sxd.swapping.dao.mybatis=debug

==========================注解方式======================

3.实体类

package com.sxd.swapping.base;

import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;

import javax.persistence.*;
import java.util.*;
import java.util.stream.Collectors;

/**
 * 基础bean
 */
@MappedSuperclass
public class BaseBean {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;// 主键 自增

    @Column(nullable = false, updatable = false)
    private Date createDate;// 创建时间

    private Date updateDate;// 修改时间

    private String updateId; // 修改人

    @Column(nullable = false)
    private String createId; // 创建人

    @Column(nullable = false)
    private String uid;     //业务主键

    @Transient
    private Integer pageNum = 0;    //分页 页号

    @Transient
    private Integer pageSize = 10;  //分页 页量

    public Long getId() {
        return id;
    }

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

    public Date getCreateDate() {
        return createDate;
    }

    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }

    public Date getUpdateDate() {
        return updateDate;
    }

    public void setUpdateDate(Date updateDate) {
        this.updateDate = updateDate;
    }

    public String getUpdateId() {
        return updateId;
    }

    public void setUpdateId(String updateId) {
        this.updateId = updateId;
    }

    public String getCreateId() {
        return createId;
    }

    public void setCreateId(String createId) {
        this.createId = createId;
    }

    public String getUid() {
        return uid;
    }

    public void setUid(String uid) {
        this.uid = uid;
    }

    public Integer getPageNum() {
        return pageNum;
    }

    public void setPageNum(Integer pageNum) {
        this.pageNum = pageNum;
    }

    public Integer getPageSize() {
        return pageSize;
    }

    public void setPageSize(Integer pageSize) {
        this.pageSize = pageSize;
    }

    public void initEntity(){
        this.createDate = new Date();
        this.createId = UUID.randomUUID().toString();//如果有当前登陆人，则初始化为当前登陆人
        this.uid = UUID.randomUUID().toString();
    }

    public void updateEntity(){
        this.updateDate = new Date();
        this.updateId = UUID.randomUUID().toString();//如果有当前登陆人，则赋值为当前登陆人
    }

    /**
     * 分页 工具方法
     * @return
     */
    public  PageRequest page(){
        return PageRequest.of(pageNum,this.pageSize);
    }

    /**
     * 分页 排序工具方法
     *
     * 中文字段排序 需要在查询出来后处理 sort无法解决中文排序的问题
     * @param map
     * @param obj
     * @return
     * @throws Exception
     */
    public  PageRequest page(Map<String,Sort.Direction> map,Object obj) throws Exception{
        //反射获取实体所有属性
        List<String> properties = Arrays.stream(obj.getClass().getDeclaredFields()).map(i->i.getName()).collect(Collectors.toList());
        Set<String> keySet = map.keySet();
        Sort sort = null;
        if (properties.containsAll(keySet)){
            for (String str:keySet){
                if (sort == null){
                    sort = Sort.by(map.get(str),str);
                }else{
                    sort = sort.and(Sort.by(map.get(str),str));
                }
            }
        }else{
            throw new Exception("排序字段非本实体字段");
        }
        return PageRequest.of(this.pageNum,this.pageSize,sort);
    }
}

package com.sxd.swapping.domain;

import com.sxd.swapping.base.BaseBean;
import lombok.Getter;
import lombok.Setter;
import org.apache.commons.lang3.StringUtils;
import org.springframework.data.jpa.domain.Specification;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import java.io.Serializable;
import java.util.*;

@Entity
@Table
@Getter
@Setter
public class HuaYangArea extends BaseBean implements Serializable {
    private static final long serialVersionUID = -1851783771574739215L;

    @Column(nullable = false)
    private String areaName;

    @Column(nullable = false)
    private Long areaPerson;

    public static Specification<HuaYangArea> where(HuaYangArea huaYangArea){

        return  new Specification<HuaYangArea>() {
            @Override
            public Predicate toPredicate(Root<HuaYangArea> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                //创建查询列表
                List<Predicate> predicates = new ArrayList<>();

                //字段areaName是否查询
                String areaName = huaYangArea.getAreaName();
                if (StringUtils.isNotBlank(areaName)){
                    predicates.add(criteriaBuilder.like(root.get("areaName"),"%"+areaName+"%"));
                }
                //字段areaPerson是否查询
                Long areaPerson = huaYangArea.getAreaPerson();
                if (areaPerson != null) {
                    predicates.add(criteriaBuilder.equal(root.get("areaPerson"),areaPerson));
                }

                return criteriaQuery.where(predicates.toArray(new Predicate[predicates.size()])).getRestriction();
            }
        };
    }

}

4.自己写的mapper映射类[实际是接口]，等同于dao层【注意@Mapper注解没有加在这个类上，是因为采用了在启动类上加@MapperScan(“Mapper类所在包路径”)的方式】

启动类代码:

package com.sxd.swapping;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

@EnableScheduling
@SpringBootApplication
@MapperScan("com.sxd.swapping.dao.mybatis")
public class SwappingApplication {

    public static void main(String[] args) {
        SpringApplication.run(SwappingApplication.class, args);
    }
}

【重点是看Mapper层的sql语句怎么写】

package com.sxd.swapping.dao.mybatis;

import com.sxd.swapping.domain.HuaYangArea;
import org.apache.ibatis.annotations.*;

import java.util.Date;
import java.util.List;

public interface HuaYangAreaMapper {

    /**
     * 根据业务主键查询
     * @param uid
     * @return
     */
    @Select("SELECT * FROM hua_yang_area where uid = #{uid}")
    @Results({
            @Result(property = "areaName",column = "area_name",javaType = String.class),
            @Result(property = "areaPerson",column = "area_person",javaType = Long.class),
            @Result(property = "createId",column = "create_id",javaType = String.class)
    })
    HuaYangArea findOne(String uid);

    /**
     * 根据数据库主键 查询
     * @param id
     * @return
     */
    @Select("SELECT * FROM hua_yang_area WHERE id = #{id}")
    @Results({
            @Result(property = "areaName",column = "area_name",javaType = String.class),
            @Result(property = "areaPerson",column = "area_person",javaType = Long.class),
            @Result(property = "createId",column = "create_id",javaType = String.class),
            @Result(property = "createDate",column = "create_date",javaType = Date.class),
            @Result(property = "updateDate",column = "update_date",javaType = Date.class)
    })
    HuaYangArea selectById(Long id);

    /**
     * 模糊查询 方法1
     * @param areaName  不传入值  则查到所有
     * @return
     */
    @Select("SELECT * FROM hua_yang_area WHERE area_name like '%${areaName}%'")
    @Results({
            @Result(property = "areaName",column = "area_name",javaType = String.class),
            @Result(property = "areaPerson",column = "area_person",javaType = Long.class),
            @Result(property = "createId",column = "create_id",javaType = String.class),
            @Result(property = "createDate",column = "create_date",javaType = Date.class),
            @Result(property = "updateDate",column = "update_date",javaType = Date.class)
    })
    List<HuaYangArea> selectByNameLike(@Param("areaName") String areaName);

    /**
     * 模糊查询 方法2
     * @param areaName  不传入值则 一条也查不到
     * @return
     */
    @Select("SELECT * FROM hua_yang_area WHERE area_name like CONCAT(CONCAT('%',#{areaName}),'%')")
    @Results({
            @Result(property = "areaName",column = "area_name",javaType = String.class),
            @Result(property = "areaPerson",column = "area_person",javaType = Long.class),
            @Result(property = "createId",column = "create_id",javaType = String.class),
            @Result(property = "createDate",column = "create_date",javaType = Date.class),
            @Result(property = "updateDate",column = "update_date",javaType = Date.class)
    })
    List<HuaYangArea> selectByNameLike2(String areaName);

    /**
     * 插入 新增
     * @param huaYangArea
     * @return
     */
    @Insert("INSERT INTO hua_yang_area(create_date,create_id,uid,area_name,area_person) VALUES (#{createDate},#{createId},#{uid},#{areaName},#{areaPerson}) ")
    void insert(HuaYangArea huaYangArea);

    /**
     * 更新   根据数据库主键更新
     * @param huaYangArea
     */
    @Update("UPDATE hua_yang_area SET update_date=#{updateDate},update_id=#{updateId},area_name=#{areaName},area_person=#{areaPerson} WHERE id=#{id}")
    void update(HuaYangArea huaYangArea);

    /**
     * 删除    根据数据库主键删除
     * @param id
     */
    @Delete("DELETE FROM hua_yang_area WHERE id=#{id}")
    void delete(Long id);

}

5.serviceImpl层【service层需要加@service()注解】

package com.sxd.swapping.service.impl;

import com.sxd.swapping.dao.jpa.HuaYangAreaDao;
import com.sxd.swapping.dao.mybatis.HuaYangAreaMapper;
import com.sxd.swapping.domain.HuaYangArea;
import com.sxd.swapping.service.HuaYangService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

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

@Service
public class HuaYangServiceImpl implements HuaYangService {

    @Autowired
    HuaYangAreaMapper huaYangAreaMapper;

    @Override
    public HuaYangArea getByUidWithMyBatis(String uid) {
        return huaYangAreaMapper.findOne(uid);
    }

    @Override
    public HuaYangArea insertWithMybatis(HuaYangArea huaYangArea) {
        huaYangAreaMapper.insert(huaYangArea);
        return huaYangAreaMapper.findOne(huaYangArea.getUid());
    }

    @Override
    public HuaYangArea updateWithMyBatis(HuaYangArea huaYangArea) {
        huaYangAreaMapper.update(huaYangArea);
        return huaYangAreaMapper.selectById(huaYangArea.getId());
    }

    @Override
    public void deleteWithMyBatis(Long id) {
        huaYangAreaMapper.delete(id);
    }

    @Override
    public HuaYangArea seleteWithMyBatis(Long id) {
        return huaYangAreaMapper.selectById(id);
    }

    @Override
    public List<HuaYangArea> selectLikeNameWithMyBatis(String areaName) {
        return huaYangAreaMapper.selectByNameLike(areaName);
    }

    @Override
    public List<HuaYangArea> selectLikeNameWithMyBatis2(String areaName) {
        return huaYangAreaMapper.selectByNameLike2(areaName);
    }

}

6.统一响应体

package com.sxd.swapping.base;

import com.sxd.swapping.util.MyException;
import lombok.Getter;
import lombok.Setter;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.BeanUtils;

import java.beans.PropertyDescriptor;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.List;

@Getter
@Setter
public class UniVerResponse<T> implements Serializable {

    private static final long serialVersionUID = 137671534756697880L;

    /**
     * 正确
     */
    public static final int SUCCESS_REQUEST = 200;
    /**
     * 参数错误返回码
     */
    public static final int ERROR_PARAMS = 100001;

    /**
     * 业务错误返回码
     */
    public static final int ERROR_BUSINESS = 200001;
    /**
     * 系统异常返回码
     */
    public static final int ERROR_SYS_EXCPTION = 500001;

    private boolean success;

    private String msg;

    private int code;

    private T obj;

    public  void beTrue(T obj){
        this.success = true;
        this.msg = "successful";
        this.code = SUCCESS_REQUEST;
        this.obj = obj;
    }

    public void  beFalse(String msg,int code,T obj){
        this.success = false;
        this.msg = msg;
        this.code = code;
        this.obj = obj;
    }

    /**
     * 对象多字段判空检查
     * 例如simplCheckField(user,"userId","userName")
     * @param obj           被检查的对象
     * @param propertys     被检查对象中的字段 可多个
     * @throws MyException
     */
    public static void checkField(Object obj,String...propertys) throws MyException{

        if(obj != null && propertys != null && propertys.length > 0){
            //字节码
            Class<? extends Object> clazz = obj.getClass();

            //遍历所有属性
            for (int i = 0; i < propertys.length; i++) {
                String property = propertys[i];
                //内省机制获取属性信息
                PropertyDescriptor pd = BeanUtils.getPropertyDescriptor(clazz,property );
                if(pd != null){
                    //获取当前字段的javabean读方法
                    Method readMethod = pd.getReadMethod();
                    if(readMethod != null){

                        Object invoke = null;

                        try {
                            invoke = readMethod.invoke(obj);
                        } catch (Exception e) {
                            throw new MyException("方法 "+ readMethod.getName() +"无法执行",UniVerResponse.ERROR_SYS_EXCPTION);
                        }

                        if(invoke != null){
                            //String类型单独处理
                            Class<?> propertyType = pd.getPropertyType();
                            if("java.lang.String".equals(propertyType.getName())){

                                if(StringUtils.isBlank((String)invoke)){
                                    throw new MyException("错误 : [ " + property + " ] 不能为空!",UniVerResponse.ERROR_PARAMS);
                                }

                            }else if("java.util.List".equals(propertyType.getName())){
                                List list = (List)invoke;
                                if(list.size() == 0){
                                    throw new MyException("错误 : [ " + property + " ] 不能为空!",UniVerResponse.ERROR_PARAMS);
                                }
                            }
                        }else{
                            throw new MyException("错误 : [ " + property + " ] 不能为空!",UniVerResponse.ERROR_PARAMS);
                        }

                    }else{
                        //抛出异常
                        throw new MyException("在 " + clazz +"中 找不到"+"[ " + property + " ] 的 读方法",UniVerResponse.ERROR_SYS_EXCPTION);
                    }

                }else{
                    //抛出异常
                    throw new MyException("在 " + clazz +"中 找不到"+"[ " + property + " ] 属性",UniVerResponse.ERROR_SYS_EXCPTION);
                }
            }
        }
    }

    /**
     * 单一字段判空检查
     * 可检查对象的单个属性判空 例如simplCheckField(user,"userId")
     * 也可做某个变量的单独判空 例如simplCheckField(userId,"userId")
     * @param obj       被检查的对象
     * @param property  被检查的对象的字段
     * @throws MyException
     */
    public static void simplCheckField(Object obj,String property) throws MyException{

        if(obj instanceof String){
            if(StringUtils.isBlank((String)obj)){
                throw new MyException("错误 : [ " + property + " ] 不能为空!",UniVerResponse.ERROR_PARAMS);
            }
        }else if(obj instanceof List){
            List list = (List)obj;
            if(list.size() == 0){
                throw new MyException("错误 : [ " + property + " ] 不能为空!",UniVerResponse.ERROR_PARAMS);
            }
        }else{
            if(obj == null){
                throw new MyException("错误 : [ " + property + " ] 不能为空!",UniVerResponse.ERROR_PARAMS);
            }
        }
    }

}

7.controller层调用即可

package com.sxd.swapping.controller;

import com.sxd.swapping.base.UniVerResponse;
import com.sxd.swapping.domain.HuaYangArea;
import com.sxd.swapping.service.HuaYangService;
import com.sxd.swapping.util.MyException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/huayangMybatis")
public class HuaYangApiWithMyBatis {

    @Autowired
    HuaYangService huaYangService;

    @PostMapping("/insert")
    public UniVerResponse<HuaYangArea> insert(@RequestBody HuaYangArea huaYangArea){
        UniVerResponse.checkField(huaYangArea,"areaName","areaPerson");
        huaYangArea.initEntity();
        UniVerResponse<HuaYangArea> response = new UniVerResponse<>();
        try {
            huaYangArea = huaYangService.insertWithMybatis(huaYangArea);
            response.beTrue(huaYangArea);
        }catch (Exception e){
            throw  new MyException("插入失败",UniVerResponse.ERROR_BUSINESS);
        }

        return response;
    }

    @PutMapping("/update")
    public UniVerResponse<HuaYangArea> update(@RequestBody HuaYangArea huaYangArea){
        UniVerResponse.checkField(huaYangArea,"id","areaName","areaPerson");
        huaYangArea.updateEntity();
        UniVerResponse<HuaYangArea> response = new UniVerResponse<>();
        try {
            huaYangArea = huaYangService.updateWithMyBatis(huaYangArea);
            response.beTrue(huaYangArea);
        }catch (Exception e){
            throw  new MyException("更新失败",UniVerResponse.ERROR_BUSINESS);
        }

        return response;
    }

    /**
     * 不传入值的查询所有
     * @param areaName
     * @return
     */
    @GetMapping("/findByNameLike")
    public UniVerResponse<List<HuaYangArea>> findAll1(String areaName){

        UniVerResponse<List<HuaYangArea>> response = new UniVerResponse<>();
        try {
            response.beTrue(huaYangService.selectLikeNameWithMyBatis(areaName));
        }catch (Exception e){
            e.printStackTrace();
            throw  new MyException("查询失败",UniVerResponse.ERROR_BUSINESS);
        }

        return response;
    }

    /**
     * 不传入值  查不到结果
     * @param areaName
     * @return
     */
    @GetMapping("/findByNameLike2")
    public UniVerResponse<List<HuaYangArea>> findAll2(String areaName){

        UniVerResponse<List<HuaYangArea>> response = new UniVerResponse<>();
        try {
            response.beTrue(huaYangService.selectLikeNameWithMyBatis2(areaName));
        }catch (Exception e){
            e.printStackTrace();
            throw  new MyException("查询失败",UniVerResponse.ERROR_BUSINESS);
        }

        return response;
    }

    /**
     * 根据 业务主键获取
     * @param uid
     * @return
     */
    @GetMapping(value = "/oneHuaYang")
    public UniVerResponse<HuaYangArea> findOne(String uid){
        UniVerResponse.simplCheckField(uid,"uid");

        UniVerResponse<HuaYangArea> response = new UniVerResponse<>();
        HuaYangArea huaYangArea = huaYangService.getByUidWithMyBatis(uid);
        response.beTrue(huaYangArea);

        return response;
    }

    /**
     * 根据主键删除
     * @param id
     * @return
     */
    @DeleteMapping(value = "/oneHuaYang")
    public UniVerResponse<String> deleteOne(Long id ){
        UniVerResponse.simplCheckField(id,"id");

        UniVerResponse<String> response = new UniVerResponse<>();
        huaYangService.deleteWithMyBatis(id);
        response.beTrue("删除成功");
        return response;
    }

}

========================================================================================================

整体看下来单独采用Mapper映射类[实际是接口]中使用注解的方式，跟使用JPA很相似,但是没有JPA写起来代码量少

========================================================================================================

==========================映射文件方式======================

8.按照配置文件中的配置，在resources下创建mapper文件夹，并创建HuaYangAreaMapper.java同名的HuaYangAreaMapper.xml映射文件

注意，

<mapper namespace="com.sxd.swapping.dao.mybatis.HuaYangAreaMapper">
标签中 标明本mapper映射文件对应的是哪个Mapper类

<select
            id="findByNameAndPersonAndCreateDate"
            parameterType="com.sxd.swapping.domain.HuaYangArea"
            resultType="com.sxd.swapping.base.HuaYangModelBean">

每个sql语句是一个单独的标签，
查询有<select>
插入有<insert>
更新有<update>
删除有<delete>

标签基本属性
每一个id对应mapper类中的 一个方法名

parameterType属性标明sql接收的入参是什么类型

resultType属性标明sql操作结果的出参是什么类型

这里分别对应了两个实体类型

select
            hy.uid uid,
            hy.create_date createDate,
            hy.update_date updateDate,
            hy.area_name areaName,
            hy.area_person areaPerson
        from
            hua_yang_area AS hy

        <where>
            1=1
            <if test="areaName != null">
                AND hy.area_name LIKE '%' #{areaName} '%'
            </if>

            <if test="areaPerson != null">
                AND hy.area_person >= #{areaPerson}
            </if>

            <if test="createDate != null">
                AND <![CDATA[hy.create_date >= #{createDate}]]>
            </if>

        </where>

查询语句
select
    数据表字段1   出参实体属性1，
    数据表字段2    出参实体属性2
from
    数据表名
where
    if 入参实体属性1 !=null
        数据表字段1 = 入参实体属性1

注意 时间类型的比较 转义字符的 处理

完整代码如下：

<?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.sxd.swapping.dao.mybatis.HuaYangAreaMapper">

    <select
            id="findByNameAndPersonAndCreateDate"
            parameterType="com.sxd.swapping.domain.HuaYangArea"
            resultType="com.sxd.swapping.base.HuaYangModelBean">

        select
            hy.uid uid,
            hy.create_date createDate,
            hy.update_date updateDate,
            hy.area_name areaName,
            hy.area_person areaPerson
        from
            hua_yang_area AS hy

        <where>
            1=1
            <if test="areaName != null">
                AND hy.area_name LIKE '%' #{areaName} '%'
            </if>

            <if test="areaPerson != null">
                AND hy.area_person >= #{areaPerson}
            </if>

            <if test="createDate != null">
                AND <![CDATA[hy.create_date >= #{createDate}]]>
            </if>

        </where>

    </select>

</mapper>

9.入参的实体类已经在最上面提供了，出参的Model

package com.sxd.swapping.base;

import lombok.Getter;
import lombok.Setter;

import java.util.Date;

/**
 * mybatis 查询返回Model封装
 */
@Getter
@Setter
public class HuaYangModelBean {

    private String uid;

    private Date createDate;

    private Date updateDate;

    private String areaName;

    private Long areaPerson;

}

10.Mapper映射类[实际是接口]中 就这个方法

11. 分别在service 和controller层调用即可【想看代码 可以看下面分页模块 顺便把这一部分的service层代码 和controller层代码贴出来了】

【这里有一个前台String类型传递给后台Date类型的错误：http://www.cnblogs.com/sxdcgaq8080/p/9055107.html】

==============================================================================================================

映射文件这种方式，就可以很肆意的写SQL了，但是这里考虑到一个问题就是不同数据库的sql语法可能有所不同，所以对于不同数据库的查询，这种方式可移植性就很劣势了。

===============================================================================================================

===========================pagehelper分页插件=====================

最后看一下mybatis分页插件的使用

12.如最上面所说的，分页jar包采用spring boot集成的这个，分页才有效

<!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper-spring-boot-starter mybatis分页插件-->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.5</version>
        </dependency>

13.在application.properties增加pagehelper相关的配置

#pagehelper mybatis分页插件
pagehelper.helperDialect=mysql
pagehelper.reasonable=true
pagehelper.supportMethodsArguments=true
pagehelper.params=count=countSql
pagehelper.returnPageInfo=check

14.映射文件mapper.xml不变更，mapper映射类[实际是接口]依旧是上面的那个方法

15.service层新增一个返回PageInfo<实体>方法

import com.github.pagehelper.PageInfo;

List<HuaYangModelBean> findByNameAndPersonAndCreateDateWithMyBatisFile(HuaYangArea huaYangArea);

PageInfo<HuaYangModelBean> findByNameAndPersonAndCreateDateWithMyBatisFileAndpagehelper(HuaYangArea huaYangArea);

service的实现

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;

@Override
    public List<HuaYangModelBean> findByNameAndPersonAndCreateDateWithMyBatisFile(HuaYangArea huaYangArea) {
        return huaYangAreaMapper.findByNameAndPersonAndCreateDate(huaYangArea);
    }

    @Override
    public PageInfo<HuaYangModelBean> findByNameAndPersonAndCreateDateWithMyBatisFileAndpagehelper(HuaYangArea huaYangArea) {
        PageHelper.startPage(huaYangArea.getPageNum(),huaYangArea.getPageSize());
        List<HuaYangModelBean> list = huaYangAreaMapper.findByNameAndPersonAndCreateDate(huaYangArea);
        PageInfo<HuaYangModelBean> pageInfo = new PageInfo<>(list);
        return pageInfo;
    }

16.设置分页统一响应体

package com.sxd.swapping.base;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import java.util.ArrayList;
import java.util.List;

/**
 * 分页 统一响应体
 * @param <T>
 */

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class PageResponse<T> {

    private boolean success;

    private String msg;

    private int code;

    private int pageNum;

    private int pageSize;

    private long total;

    private List<T> rows = new ArrayList<T>();

    public  void beTrue(long total,List<T> rows){
        this.success = true;
        this.msg = "successful";
        this.code = UniVerResponse.SUCCESS_REQUEST;
        this.total = total;
        this.rows = rows;
    }

    public  void beTrue(int pageNum,int pageSize,long total,List<T> rows){
        this.success = true;
        this.msg = "successful";
        this.code = UniVerResponse.SUCCESS_REQUEST;
        this.pageNum = pageNum;
        this.pageSize = pageSize;
        this.total = total;
        this.rows = rows;
    }

    public void  beFalse(String msg,int code){
        this.success = false;
        this.msg = msg;
        this.code = code;
        this.total = 0;
        this.rows = null;
    }
}

17.controller层调用

 /**
     * 根据 三个字段 查询
     * 使用mybatis映射文件
     * @param huaYangArea
     * @return
     */
    @GetMapping(value = "/findBy3")
    public UniVerResponse<List<HuaYangModelBean>> findByNameAndPersonAndCreateDate(HuaYangArea huaYangArea){
        UniVerResponse.checkField(huaYangArea,"areaName","areaPerson","createDate");
        UniVerResponse<List<HuaYangModelBean>> response = new UniVerResponse<>();

        try {
            List<HuaYangModelBean> list = huaYangService.findByNameAndPersonAndCreateDateWithMyBatisFile(huaYangArea);
            response.beTrue(list);
        }catch (Exception e){
            throw new MyException("查询错误",UniVerResponse.ERROR_BUSINESS,e);
        }

        return response;
    }

    /**
     * 根据三个字段 映射文件 查询
     *
     * 分页查询
     * @param huaYangArea
     * @return
     */
    @GetMapping(value = "/findBy3Page")
    public PageResponse<HuaYangModelBean> findByNameAndPersonAndCreateDatePage(HuaYangArea huaYangArea){
        UniVerResponse.checkField(huaYangArea,"areaName","areaPerson","createDate","pageNum","pageSize");
        PageResponse<HuaYangModelBean> response = new PageResponse<>();

        try {
            PageInfo<HuaYangModelBean> pageInfo = huaYangService.findByNameAndPersonAndCreateDateWithMyBatisFileAndpagehelper(huaYangArea);
            response.beTrue(pageInfo.getPageNum(),pageInfo.getPageSize(),pageInfo.getTotal(),pageInfo.getList());
        }catch (Exception e){
            throw new MyException("查询错误",UniVerResponse.ERROR_BUSINESS,e);
        }

        return response;
    }

18.测试查询，分页 的pageNum = 0 和pageNum = 1都是返回第一页的数据

满足条件的 总共13条数据，

查询pageNum = 0  pageSize = 10

查询 参数如下：

查询语句打印日志如下：

2018-05-18 14:05:19.469 DEBUG 8188 --- [nio-9666-exec-8] H.findByNameAndPersonAndCreateDate_COUNT : ==>  Preparing: select count(0) from (select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ?) tmp_count
2018-05-18 14:05:19.470 DEBUG 8188 --- [nio-9666-exec-8] H.findByNameAndPersonAndCreateDate_COUNT : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp)
2018-05-18 14:05:19.471 DEBUG 8188 --- [nio-9666-exec-8] H.findByNameAndPersonAndCreateDate_COUNT : <==      Total: 1
2018-05-18 14:05:19.472 DEBUG 8188 --- [nio-9666-exec-8] s.d.m.H.findByNameAndPersonAndCreateDate : ==>  Preparing: select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ? LIMIT ?
2018-05-18 14:05:19.473 DEBUG 8188 --- [nio-9666-exec-8] s.d.m.H.findByNameAndPersonAndCreateDate : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp), 10(Integer)
2018-05-18 14:05:19.476 DEBUG 8188 --- [nio-9666-exec-8] s.d.m.H.findByNameAndPersonAndCreateDate : <==      Total: 10

查询结果如下：

=============================================================================================================

查询pageNum = 1  pageSize = 10

查询 参数如下：

查询语句日志打印如下：

2018-05-18 14:03:38.142 DEBUG 8188 --- [nio-9666-exec-3] H.findByNameAndPersonAndCreateDate_COUNT : ==>  Preparing: select count(0) from (select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ?) tmp_count
2018-05-18 14:03:38.143 DEBUG 8188 --- [nio-9666-exec-3] H.findByNameAndPersonAndCreateDate_COUNT : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp)
2018-05-18 14:03:38.145 DEBUG 8188 --- [nio-9666-exec-3] H.findByNameAndPersonAndCreateDate_COUNT : <==      Total: 1
2018-05-18 14:03:38.146 DEBUG 8188 --- [nio-9666-exec-3] s.d.m.H.findByNameAndPersonAndCreateDate : ==>  Preparing: select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ? LIMIT ?
2018-05-18 14:03:38.147 DEBUG 8188 --- [nio-9666-exec-3] s.d.m.H.findByNameAndPersonAndCreateDate : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp), 10(Integer)
2018-05-18 14:03:38.151 DEBUG 8188 --- [nio-9666-exec-3] s.d.m.H.findByNameAndPersonAndCreateDate : <==      Total: 10

结果都是下面这样：

显示pageNum 都是 为1

=============================================================================================================

查询pageNum = 2  pageSize = 10

查询参数如下：

查询语句日志打印如下：

2018-05-18 14:02:31.734 DEBUG 8188 --- [nio-9666-exec-1] H.findByNameAndPersonAndCreateDate_COUNT : ==>  Preparing: select count(0) from (select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ?) tmp_count
2018-05-18 14:02:31.753 DEBUG 8188 --- [nio-9666-exec-1] H.findByNameAndPersonAndCreateDate_COUNT : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp)
2018-05-18 14:02:31.766 DEBUG 8188 --- [nio-9666-exec-1] H.findByNameAndPersonAndCreateDate_COUNT : <==      Total: 1
2018-05-18 14:02:31.772 DEBUG 8188 --- [nio-9666-exec-1] s.d.m.H.findByNameAndPersonAndCreateDate : ==>  Preparing: select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ? LIMIT ?, ?
2018-05-18 14:02:31.772 DEBUG 8188 --- [nio-9666-exec-1] s.d.m.H.findByNameAndPersonAndCreateDate : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp), 10(Integer), 10(Integer)
2018-05-18 14:02:31.774 DEBUG 8188 --- [nio-9666-exec-1] s.d.m.H.findByNameAndPersonAndCreateDate : <==      Total: 3

查询结果如下：

=============================================================================================================

查询pageNum = 3  pageSize = 10

查询参数如下：

查询语句打印日志如下：

2018-05-18 14:11:52.633 DEBUG 8188 --- [nio-9666-exec-8] H.findByNameAndPersonAndCreateDate_COUNT : ==>  Preparing: select count(0) from (select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ?) tmp_count
2018-05-18 14:11:52.634 DEBUG 8188 --- [nio-9666-exec-8] H.findByNameAndPersonAndCreateDate_COUNT : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp)
2018-05-18 14:11:52.636 DEBUG 8188 --- [nio-9666-exec-8] H.findByNameAndPersonAndCreateDate_COUNT : <==      Total: 1
2018-05-18 14:11:52.638 DEBUG 8188 --- [nio-9666-exec-8] s.d.m.H.findByNameAndPersonAndCreateDate : ==>  Preparing: select hy.uid uid, hy.create_date createDate, hy.update_date updateDate, hy.area_name areaName, hy.area_person areaPerson from hua_yang_area AS hy WHERE 1=1 AND hy.area_name LIKE '%' ? '%' AND hy.area_person >= ? AND hy.create_date >= ? LIMIT ?, ?
2018-05-18 14:11:52.639 DEBUG 8188 --- [nio-9666-exec-8] s.d.m.H.findByNameAndPersonAndCreateDate : ==> Parameters: 华阳(String), 7000(Long), 2018-05-16 00:00:00.0(Timestamp), 10(Integer), 10(Integer)
2018-05-18 14:11:52.641 DEBUG 8188 --- [nio-9666-exec-8] s.d.m.H.findByNameAndPersonAndCreateDate : <==      Total: 3

查询结果如下：

==================================================================================

好了  spring boot 2.0+mybatis 暂时告一段落。