Sprintboot+MyBatis配置

编程语言 2019-03-18 00:18:36 阅读次数: 0

Sprintboot+MyBatis配置

一、基本配置

  • pom.xml配置
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.0.0</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
  • application.properties配置
# mysql配置
spring.datasource.url=jdbc:mysql://192.168.188.11:3306/wechat_store?useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=666666
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

二、基本使用（基于注解）

  • 创建实体类
package net.ken.shop.wx.domain.po;

import lombok.Data;

@Data
public class UserPO {

    public UserPO(int id, String userName) {
        this.id = id;
        this.userName = userName;
    }

    private int id;

    private String userName;
}
  • 创建Mapper类
package net.ken.shop.wx.mapper;

import net.ken.shop.wx.domain.po.UserPO;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

//@Mapper
public interface UserMapper {

    @Insert("insert into user(id,user_name) values(#{id},#{userName})")
    int insertT(UserPO userPO);

    @Delete("delete from user where id = #{id}")
    int deleteById(int id);

    @Delete("delete from user")
    int deleteAll();

    @Update("update user set user_name=#{userName} where id = #{id}")
    int updateT(UserPO userPO);

    @Select("select * from user where id = #{id}")
    UserPO findUserById(int id);

    @Select("select * from user")
    List<UserPO> findAll();
}
  • 启动类中增加扫描Mapper类
package net.ken.shop;

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

@SpringBootApplication
@MapperScan(basePackages= {"net.ken.shop.wx.mapper"})
public class ShopApplication {
    public static void main(String[] args) {
        SpringApplication.run(ShopApplication.class, args);
    }
}
  • 测试类
package net.ken.shop;

import net.ken.shop.wx.domain.po.UserPO;
import net.ken.shop.wx.mapper.UserMapper;
import org.junit.Assert;
import org.junit.Before;
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;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MybatisTests {

    @Autowired
    UserMapper userMapper;

    @Before
    public void testBefore(){
        userMapper.deleteAll();
    }

    @Test
    public void testUserMapper(){
        Assert.assertEquals(1,userMapper.insertT(new UserPO(1,"ken")));
        Assert.assertEquals(1,userMapper.deleteById(1));
        userMapper.insertT(new UserPO(1,"ken"));
        Assert.assertEquals(1,userMapper.updateT(new UserPO(1,"joy")));
        Assert.assertEquals("joy",userMapper.findUserById(1).getUserName());
        userMapper.insertT(new UserPO(2,"ken"));
        Assert.assertEquals(2,userMapper.findAll().size());
    }
}

  • 执行测试类后，数据库中数据

  • 备注1

Mapper需要添加注解才能被springboot扫描到并加入容器管理，方式如下两种,个人推荐方式2

  1. Mapper类中上增加 @Mapper
  2. 启动类中增加 @MapperScan(basePackages= {“net.ken.shop.wx.mapper”})
  • 备注2

数据库中字段为下划线“user_name”，po类中为驼峰"userName",查询的时候会自动转换

三、基本使用（基于xml）

  • application.properties配置
# mybatis 配置 resource路径下
mybatis.mapper-locations=classpath:mapper/*Mapper.xml
  • 启动类配置
package net.havejoy.springboot_mybatis_xml;

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

@SpringBootApplication
@MapperScan("net.havejoy.mapper")
public class SpringbootMybatisXmlApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringbootMybatisXmlApplication.class, args);
    }
}
  • 创建实体类
package net.havejoy.domain;

import lombok.Data;

@Data
public class UserPO {
    public UserPO(int id, String userName) {
        this.id = id;
        this.userName = userName;
    }
    private int id;
    private String userName;
}
  • 创建Mapper类
package net.havejoy.mapper;

import net.havejoy.domain.UserPO;

import java.util.List;

public interface UserMapper {
    UserPO findById(int id);
    List<UserPO> findAll();
    void insertT(UserPO userPO);
    void updateT(UserPO userPO);
    void deleteById(int id);
    void deleteAll();
}
  • 创建Mapper.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="net.havejoy.mapper.UserMapper">

    <select id="findById" resultType="net.havejoy.domain.UserPO" parameterType="java.lang.Integer">
      select *  from user where id = #{id}
    </select>

    <select id="findAll" resultType="net.havejoy.domain.UserPO">
        select * from user
    </select>

    <insert id="insertT" parameterType="net.havejoy.domain.UserPO">
      insert into user (id,user_name) values (#{id},#{userName})
    </insert>

    <update id="updateT" parameterType="net.havejoy.domain.UserPO">
        update user set user_name=#{userName} where id = #{id}
    </update>

    <delete id="deleteById" parameterType="java.lang.Integer">
      delete from user where id = #{id}
    </delete>

    <delete id="deleteAll" parameterType="java.lang.Integer">
      delete from user
    </delete>
</mapper>
  • 测试类
package net.havejoy.springboot_mybatis_xml;

import net.havejoy.domain.UserPO;
import net.havejoy.mapper.UserMapper;
import org.junit.Assert;
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;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootMybatisXmlApplicationTests {

    @Autowired
    UserMapper userMapper;

    @Test
    public void contextLoads() {
    }

    @Test
    public void testUserMapper(){
        userMapper.deleteAll();
        Assert.assertEquals(0,userMapper.findAll().size());

        userMapper.insertT(new UserPO(1,"ken"));
        Assert.assertEquals("ken",userMapper.findById(1).getUserName());

        userMapper.updateT(new UserPO(1,"joy"));
        Assert.assertEquals("joy",userMapper.findById(1).getUserName());

        userMapper.deleteById(1);
        Assert.assertEquals(0,userMapper.findAll().size());

        userMapper.insertT(new UserPO(1,"ken"));
        userMapper.insertT(new UserPO(2,"joy"));
        Assert.assertEquals(2,userMapper.findAll().size());
    }
}

四、关联查询（基于注解）

对象包含：

  1. student：学生
  2. class：班级
  3. teacher：教师

相互关系：
班级和教师：一对一
班级和学生：一对多

  • 数据库初始化：
CREATE TABLE class (
  c_id int(11) NOT NULL AUTO_INCREMENT,
  c_name varchar(255) DEFAULT NULL,
  teacher_id int(11) DEFAULT NULL,
  PRIMARY KEY (c_id)
);

CREATE TABLE teacher (
  t_id int(11) NOT NULL AUTO_INCREMENT,
  t_name varchar(255) DEFAULT NULL,
  PRIMARY KEY (t_id)
);

CREATE TABLE student (
  s_id int(11) NOT NULL AUTO_INCREMENT,
  s_name varchar(255) DEFAULT NULL,
  class_id int(11) DEFAULT NULL,
  PRIMARY KEY (s_id)
);


INSERT INTO class VALUES ('1', 'class1', '1');
INSERT INTO class VALUES ('2', 'class2', '2');

INSERT INTO teacher VALUES ('1', 'teacher1');
INSERT INTO teacher VALUES ('2', 'teacher2');

INSERT INTO student VALUES ('1', 'student1', '1');
INSERT INTO student VALUES ('2', 'student2', '1');
  • 创建实体类：
package net.havejoy.springboot_mybatis_annotation.domain;

import lombok.Data;

import java.util.List;

@Data
public class Class {
    private int id;
    private String name;
    private Teacher teacher;
    private List<Student> students;
}

package net.havejoy.springboot_mybatis_annotation.domain;

import lombok.Data;

@Data
public class Student {
    private int id;
    private String name;
    private String classId;
    private Class aClass;
}

package net.havejoy.springboot_mybatis_annotation.domain;

import lombok.Data;

@Data
public class Teacher {
    public Teacher(String name){
        this.name = name;
    }
    private int id;
    private String name;
}
  • 创建Mapper
package net.havejoy.springboot_mybatis_annotation.mapper;

import net.havejoy.springboot_mybatis_annotation.domain.Class;
import org.apache.ibatis.annotations.*;

public interface ClassMapper {
    @Select("select * from class where c_id = #{id}")
    @Results({
            @Result(property = "id", column = "c_id"),
            @Result(property = "name", column = "c_name"),
            @Result(property = "teacher", column = "teacher_id", one = @One(select = "net.havejoy.springboot_mybatis_annotation.mapper.TeacherMapper.findById")),
            @Result(property = "students", column = "c_id", many = @Many(select = "net.havejoy.springboot_mybatis_annotation.mapper.StudentMapper.findByClassId"))
    })
    Class findById(int id);
}

package net.havejoy.springboot_mybatis_annotation.mapper;

import net.havejoy.springboot_mybatis_annotation.domain.Student;
import org.apache.ibatis.annotations.One;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;

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

public interface StudentMapper {
    @Select("select * from student where class_id = #{classId}")
    @Results({
            @Result(property = "id", column = "s_id"),
            @Result(property = "name", column = "s_name"),
            @Result(property = "classId", column = "class_id"),
            @Result(property = "aClass",column = "class_id",one = @One(select = "net.havejoy.springboot_mybatis_annotation.mapper.ClassMapper.findById"))
    })
    List<Student> findByClassId(int classId);

    @Select("select s_name,class_id from student where class_id = #{classId}")
    List<Map<String,Object>> findCustomByClassId(int ClassId);
}

package net.havejoy.springboot_mybatis_annotation.mapper;

import net.havejoy.springboot_mybatis_annotation.domain.Teacher;
import org.apache.ibatis.annotations.*;

public interface TeacherMapper {

    @Insert("insert into teacher (t_name) value(#{name})")
    @Options(useGeneratedKeys = true, keyProperty = "id", keyColumn = "t_id")
    int insert(Teacher teacher);

    @Select("select * from teacher where t_id = #{id}")
    @Results({
            @Result(property = "id", column = "t_id"),
            @Result(property = "name", column = "t_name")}
    )
    Teacher findById(int id);
}

说明

  1. @Options(useGeneratedKeys = true, keyProperty = “id”, keyColumn = “t_id”)：
    用于返回主键
  2. @Result(property = “id”, column = “t_id”)
    property为类的属性名称，column为数据库字段。
  3. @Result(property = “aClass”,column = “class_id”,one = @One(select = “net.havejoy.springboot_mybatis_annotation.mapper.ClassMapper.findById”)
    one = @One(select=“单对象查询方法，条件为column中的字段”)
  4. @Result(property = “students”, column = “c_id”, many = @Many(select = “net.havejoy.springboot_mybatis_annotation.mapper.StudentMapper.findByClassId”)
    many = @Many(select = “多对象查询方法，条件为column中的字段”)
  • 创建Mapper
package net.havejoy.springboot_mybatis_annotation;

import net.havejoy.springboot_mybatis_annotation.domain.Class;
import net.havejoy.springboot_mybatis_annotation.domain.Student;
import net.havejoy.springboot_mybatis_annotation.domain.Teacher;
import net.havejoy.springboot_mybatis_annotation.mapper.ClassMapper;
import net.havejoy.springboot_mybatis_annotation.mapper.StudentMapper;
import net.havejoy.springboot_mybatis_annotation.mapper.TeacherMapper;
import org.junit.Assert;
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 java.util.ArrayList;
import java.util.List;
import java.util.Map;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootMybatisAnnotationApplicationTests {
    @Autowired
    TeacherMapper teacherMapper;
    @Autowired
    ClassMapper classMapper;
    @Autowired
    StudentMapper studentMapper;

    @Test
    public void testTeacherMapper() {
        Teacher teacher = new Teacher("daf");
        Assert.assertEquals(1,teacherMapper.insert(teacher));
        Assert.assertEquals(7,teacher.getId());
        Assert.assertEquals("teacher1",teacherMapper.findById(1).getName());
    }

    @Test
    public void testClassMapper(){
        Class class1 = classMapper.findById(1);
        Assert.assertEquals("teacher1",class1.getTeacher().getName());
        Assert.assertEquals(2,class1.getStudents().size());
    }

    @Test
    public void testStudent(){
        List<Student> list1 = studentMapper.findByClassId(1);
        Assert.assertEquals(2,list1.size());
        List<Map<String,Object>> list = studentMapper.findCustomByClassId(1);
        Assert.assertEquals(1,list.get(0).get("class_id"));
    }
}

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