Spring Boot學習筆記（十一）Spring Boot 集成 MyBatis —— 實戰篇

Spring Boot 集成 MyBatis —— 實戰篇

訪問 https://start.spring.io/，初始化Spring Boot項目
解壓之後用 IDEA 打開
項目結構

pom.xml 文件

除了必要的mybatis-spring-boot-starter之外，其中有個commons-lang3包，它包含許多工具類，比如常用的判斷字符串是否爲空，快速複寫實體類的 toString() 方法等

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>wen</groupId>
    <artifactId>sbmybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sbmybatis</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.6</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <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>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

application.properties:

mybatis.config-locations：對應mybatis-config.xml路徑，並在mybatis-config.xml配置Mybatis基礎屬性
mybatis.mapper-locations：配置Mapper對應的XML文件路徑
mybatis.type-aliases-package：對應實體類路徑
spring.datasource.*：數據源配置

mybatis.config-locations=classpath:mybatis/mybatis-config.xml
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
mybatis.type-aliases-package=wen.sbmybatis.model
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/sbl?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone = GMT
rEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=

啓動類 SbmybatisApplication.java

在啓動類中添加對 Mapper 包掃描 @MapperScan ，Spring Boot 啓動的時候會自動加載包路徑下的Mapper
或者直接在 Mapper 類上面添加註解 @Mapper ，不過代碼上的方式更省力

package wen.sbmybatis;

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

@SpringBootApplication
@MapperScan("wen.sbmybatis.mapper")
public class SbmybatisApplication {

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

}

mybatis-config.xml

主要配置常用的 typeAliases，設置類型別名爲 Java 類型只用後綴名。它只和 XML 配置有關，用來減少類完全限定名的冗餘

<configuration>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer"/>
        <typeAlias alias="Long" type="java.lang.Long"/>
        <typeAlias alias="HashMap" type="java.util.HashMap"/>
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap"/>
        <typeAlias alias="ArrayList" type="java.util.ArrayList"/>
        <typeAlias alias="LinkedList" type="java.util.LinkedList"/>
    </typeAliases>
</configuration>

數據庫設置：
- 先了解一下表結構，數據庫存在即可，Spring Boot 會根據實體類自動創建

負責性別的枚舉類：

package wen.sbmybatis.enums;

public enum GenderEnum {
    FEMALE, MALE;
}

User.java

package wen.sbmybatis.model;

import wen.sbmybatis.enums.GenderEnum;

public class User {

    private Long id;
    private String username;
    private String password;
    private GenderEnum gender;
    private String nickname;


    public User() {
        super();
    }

    public User(String username, String password, GenderEnum gender) {
        super();
        this.username = username;
        this.password = password;
        this.gender = gender;
    }

    @Override
    public String toString() {
        return "username " + this.username + ", password " + this.password + "gender " + gender.name();
    }

    public Long getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public GenderEnum getGender() {
        return gender;
    }

    public void setGender(GenderEnum gender) {
        this.gender = gender;
    }

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }
}

分頁的Page.java：

currentPage: 當前的頁數，默認0爲第一頁
totalPage：總共的頁數
totalNumber：總共的記錄數
list：每頁記錄集合

package wen.sbmybatis.model;

import java.io.Serializable;
import java.util.List;

public class Page<E> implements Serializable {

    private int currentPage = 0;

    private long totalPage;

    private long totalNumber;

    private List<E> list;

    public Page(long totalPage, long totalNumber, List<E> list) {
        this.totalPage = totalPage;
        this.totalNumber = totalNumber;
        this.list = list;
    }
}

這個小項目是實體類操作與分頁查詢一起實現的，所以在UserMapperTest獲得Page實體類的時候需要提供相關參數，所以需要建立PageParam.java 和 UserParam.java來獲取參數：

PageParam.java:

package wen.sbmybatis.param;

public class PageParam {

    private int beginLine;
    private Integer pageSize = 3;
    private Integer currentPage = 0;

    public int getBeginLine() {
        return pageSize * currentPage;
    }

    public void setBeginLine(int beginLine) {
        this.beginLine = beginLine;
    }

    public Integer getPageSize() {
        return pageSize;
    }

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

    public Integer getCurrentPage() {
        return currentPage;
    }

    public void setCurrentPage(Integer currentPage) {
        this.currentPage = currentPage;
    }
}

UserParam.java:

package wen.sbmybatis.param;

public class UserParam extends PageParam {

    private String username;
    private String gender;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }
}

底層操作數據庫代碼 UserMapper.xml：

<mapper namespace="wen.sbmybatis.mapper.UserMapper"> 指名對應Mapper類地址
<resultMap id="BaseResultMap" type="wen.sbmybatis.model.User"> 配置表結構和類的對應關係

<?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="wen.sbmybatis.mapper.UserMapper">
    <resultMap id="BaseResultMap" type="wen.sbmybatis.model.User">
        <id column="id" property="id" jdbcType="BIGINT"/>
        <result column="username" property="username" jdbcType="VARCHAR"/>
        <result column="password" property="password" jdbcType="VARCHAR"/>
        <result column="gender" property="gender" javaType="wen.sbmybatis.enums.GenderEnum"/>
        <result column="nickname" property="nickname" jdbcType="VARCHAR"/>
    </resultMap>

    <sql id="BaseColumnList">id, username, password, gender, nickname</sql>

    <select id="getAll" resultMap="BaseResultMap">
        select
        <include refid="BaseColumnList"/>
        from user
    </select>

    <select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap">
        select
        <include refid="BaseColumnList"/>
        from user where id = #{id}
    </select>

    <insert id="insert" parameterType="wen.sbmybatis.model.User">
        insert into user (username,password,gender) values (#{username}, #{password}, #{gender})
    </insert>

    <update id="update" parameterType="wen.sbmybatis.model.User">
        update user set
        <if test="username != null">username = #{username},</if>
        <if test="password != null">password = #{password},</if>
        nickname = #{nickname} where id = #{id}
    </update>

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

    <!-- 分頁查詢 -->
    <sql id="BaseWhereList">
        <if test="username != null and username != ''">
            and username = #{username}
        </if>

        <if test="gender != null and gender != ''">
            and gender = #{gender}
        </if>
    </sql>

    <select id="getList" resultMap="BaseResultMap" parameterType="wen.sbmybatis.param.UserParam">
        select
        <include refid="BaseColumnList"/>
        from user where 1 = 1
        <include refid="BaseWhereList"/>
        order by id desc
        limit #{beginLine}, #{pageSize}
    </select>

    <select id="getCount" resultType="Integer" parameterType="wen.sbmybatis.param.UserParam">
        select count(1) from user where 1 = 1
        <include refid="BaseWhereList"></include>
    </select>
</mapper>

mapper層，一定要與上文的UserMapper.xml的id 相對應：

package wen.sbmybatis.mapper;

import wen.sbmybatis.model.User;
import wen.sbmybatis.param.UserParam;

import java.util.List;

public interface UserMapper {

    List<User> getAll();

    User getOne(Long id);

    void insert(User user);

    void update(User user);

    void delete(Long id);

    List<User> getList(UserParam userParam);

    int getCount(UserParam userParam);
}

對userMapper進行測試的 UserMapperTest.java：

package wen.sbmybatis.mapper;

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 wen.sbmybatis.enums.GenderEnum;
import wen.sbmybatis.model.Page;
import wen.sbmybatis.model.User;
import wen.sbmybatis.param.UserParam;

import java.util.List;

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

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testInsert() throws Exception {
        userMapper.insert(new User("aa", "a123456", GenderEnum.FEMALE));
        userMapper.insert(new User("bb", "b123456", GenderEnum.MALE));
        userMapper.insert(new User("cc", "c123456", GenderEnum.FEMALE));
        Assert.assertEquals(9, userMapper.getAll().size());
    }

    @Test
    public void testQuery() throws Exception {
        List<User> users = userMapper.getAll();
        if (users == null || users.size() == 0) {
            System.out.println("is null");
        } else {
            System.out.println(users.toString());
        }
    }

    @Test
    public void TestUpdate() throws Exception {
        User user = userMapper.getOne(29L);
        System.out.println(user.toString());
        user.setNickname("papa");
        userMapper.update(user);
        Assert.assertTrue("papa".equals(userMapper.getOne(29L).getNickname()));
    }

    @Test
    public void testPage() {

        UserParam userParam = new UserParam();
        userParam.setGender(GenderEnum.FEMALE.toString());
        userParam.setCurrentPage(0);

        // 總個數
        int totalNumber = userMapper.getAll().size();
        // 總頁數
        int totalPage = totalNumber / (userParam.getPageSize()) + 1;
        // 數據集
        List<User> users = userMapper.getList(userParam);

        Page page = new Page(totalPage, totalNumber, users);

        System.out.println("*****  page info *******");
        System.out.println(page.getCurrentPage());
        System.out.println(page.getTotalNumber());
        System.out.println(page.getTotalPage());
        System.out.println(page.getList());
    }
}

測試結果：

下一篇：Spring Boot學習筆記（十二）MyBatis Druid 多數據源、Spring Boot 集成 Druid—— 概念與實戰

Spring Boot學習筆記（十一）Spring Boot 集成 MyBatis —— 實戰篇

Spring Boot 集成 MyBatis —— 實戰篇

訪問 https://start.spring.io/，初始化Spring Boot項目

解壓之後用 IDEA 打開

項目結構

pom.xml 文件

application.properties:

啓動類 SbmybatisApplication.java

mybatis-config.xml

數據庫設置：

User.java

分頁的Page.java：

PageParam.java:

UserParam.java:

底層操作數據庫代碼 UserMapper.xml：

mapper層，一定要與上文的UserMapper.xml的id 相對應：

對userMapper進行測試的 UserMapperTest.java：

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Spring Boot org.hibernate.LazyInitializationException: could not initialize proxy [XX.#1]

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Spring Boot學習筆記（十一）Spring Boot 集成 MyBatis —— 實戰篇

Spring Boot 集成 MyBatis —— 實戰篇

訪問 https://start.spring.io/， 初始化Spring Boot項目

解壓之後用 IDEA 打開

項目結構

pom.xml 文件

application.properties:

啓動類 SbmybatisApplication.java

mybatis-config.xml

數據庫設置：

User.java

分頁的Page.java：

PageParam.java:

UserParam.java:

底層操作數據庫代碼 UserMapper.xml：

mapper層，一定要與上文的UserMapper.xml的id 相對應：

對userMapper進行測試的 UserMapperTest.java：

訪問 https://start.spring.io/，初始化Spring Boot項目