MyBatis基礎練習

項目目錄結構：

 

 

依賴包：

<dependencies>
        <!--單測-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!--數據庫-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.11</version>
        </dependency>

        <!--MyBatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.4</version>
        </dependency>

        <!--到slf4j與log4j的關聯jar包，通過這個東西，將對slf4j接口的調用轉換為對log4j的調用，不同的日志實現框架，這個轉換工具不同-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
            <scope>test</scope>
        </dependency>

        <!--alibaba 數據源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>

    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

 

實體類：

public class Department {

    private int departmentId;
    private String departmentName;

    public int getDepartmentId() {
        return departmentId;
    }

    public void setDepartmentId(int departmentId) {
        this.departmentId = departmentId;
    }

    public String getDepartmentName() {
        return departmentName;
    }

    public void setDepartmentName(String departmentName) {
        this.departmentName = departmentName;
    }

    public Department() {
    }

    public Department(int departmentId, String departmentName) {
        this.departmentId = departmentId;
        this.departmentName = departmentName;
    }

    @Override
    public String toString() {
        return "Department{" +
                "departmentId=" + departmentId +
                ", departmentName='" + departmentName + '\'' +
                '}';
    }
}

mybatis-config.xml配置

<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--配置的屬性都是可外部配置且可動態替換的-->
    <properties resource="database.properties" />


    <settings>
        <setting name="logImpl" value="SLF4J"/>
    </settings>

    <!--定義別名,存在的意義僅在於用來減少類完全限定名的冗余。-->
    <typeAliases>
        <!--使用掃描包，掃描指定包下的所有類，掃描之后的別名就是類名（不區分大小寫），建議使用的時候和類名一致。-->
        <package name="cn.pojo"/>
    </typeAliases>

    <!--環境數據源-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="cn.util.DruidDataSourceFactory">
                <property name="driverClassName" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>

    <!--告訴 MyBatis 到哪里查找sql映射語句-->
    <mappers>
        <mapper resource="mapper/PracticeMapper.xml" />
    </mappers>

</configuration>

工具類：

MyBatisUtil

public class MyBatisUtil {
    //創建SqlSessionFactory工廠
    public static SqlSessionFactory factory;

    static {
        InputStream is = null;
        try {
            //讀取mybatis-config.xml
            is = Resources.getResourceAsStream("mybatis-config.xml");
            factory = new SqlSessionFactoryBuilder().build(is);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession createSqlSession(){
        return factory.openSession(false);//關閉自動提交事物
    }

    public static void closeSqlSession(SqlSession sqlSession){
        if(null!=sqlSession){
            sqlSession.close();
        }
    }
}

阿里雲Druid數據源類

public class DruidDataSourceFactory extends PooledDataSourceFactory {
    public DruidDataSourceFactory(){
        this.dataSource = new DruidDataSource();
    }
}

database.properties

jdbc.driver:com.mysql.cj.jdbc.Driver
jdbc.url:jdbc:mysql://localhost:3306/tests?characterEncoding=utf8&useSSL=false&serverTimezone=UTC
jdbc.username:root
jdbc.password:123456

log4j.properties

### set log levels ###
log4j.rootLogger = DEBUG,Console,File

###  Output To Console  ###
log4j.appender.Console=org.apache.log4j.ConsoleAppender
log4j.appender.Console.Target=System.out
log4j.appender.Console.layout=org.apache.log4j.PatternLayout
#log4j.appender.stdout.layout.ConversionPattern = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n
#log4j.appender.Console.layout.ConversionPattern= [%p] %d{yyyy-MM-dd HH\:mm\:ss,SSS}  %c{1}:%L - %m%n
log4j.appender.Console.layout.ConversionPattern= %d{ABSOLUTE} %5p %c{1}:%L - %m%n
#log4j.appender.File.layout.ConversionPattern=[%p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c]%m%n

### Output To File ###
log4j.appender.File=org.apache.log4j.RollingFileAppender 
log4j.appender.File.File=d:\\mylog.log
#log4j.appender.File.DatePattern=_yyyyMMdd'.log'
log4j.appender.File.MaxFileSize=10MB
#log4j.appender.File.Threshold=ALL
log4j.appender.File.layout=org.apache.log4j.PatternLayout
log4j.appender.File.layout.ConversionPattern=[%p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c]%m%n

dao

public interface PracticeMapper {
    //查詢所有部門
    public List<Department> queryDepartmentList();

    //根據部門ID，查詢單個部門信息
    public Department queryDepartmentByDepartmentId(@Param("departmentId")Integer departmentId);

    /**
     * 根據部門名稱，模糊查詢部門信息
     * @param departmentName
     * @return
     */
    public List<Department> queryDepartmentListLikeByDepartmentName(@Param("departmentName")String departmentName);

    //添加一個部門
    public Integer insertDepartmentList(Department department);

    //刪除一個部門，根據部門ID
    public Integer deleteDepartmentByDepartmentId(@Param("departmentId")Integer departmentId);

    //修改一個部門，根據部門ID
    public Integer updateDepartentByDepartmentId(@Param("departmentName")String departmentName,@Param("departmentId")Integer departmentId);

    //如果輸入了部門名稱，就按部門名稱來查詢，否則查詢所有部門
    public List<Department> queryDepartmentIf(@Param("departmentName")String departmentName);

    //where和if  如果有部門名稱和部門ID，查詢單個部門，否則查詢所有部門
    public List<Department> queryDepartmentIfAndTrim(Department department);

    //if+set進行更新操作
    public Integer updateDepartmentIfAndSet(Department department);

    //foreach 根據部門ID查詢多條信息
    public List<Department> queryDepartmentByArrayDepartmentId(Integer[] departmentId);

    //List類型的foreach迭代
    public List<Department> queryDepartmentByListDepartmentId(List<Integer> departmentId);
}

PracticeMapper.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="cn.dao.PracticeMapper">

    <!--開啟mybatis的二級緩存-->
    <!--
        配置創建了一個 FIFO 緩存，每隔 60 秒刷新，最多可以存儲結果對象或列表的 512 個引用，
        而且返回的對象被認為是只讀的，因此對它們進行修改可能會在不同線程中的調用者產生沖突。
    -->
    <!--
        二級緩存是事務性的。
        這意味着，當 SqlSession 完成並提交時，或是完成並回滾，
        但沒有執行 flushCache=true 的 insert/delete/update 語句時，緩存會獲得更新。
        flushCache=true：將其設置為 true 后，只要語句被調用，都會導致本地緩存和二級緩存被清空，默認值：（對 insert、update 和 delete 語句）true。
    -->
    <cache
            eviction="FIFO"
            flushInterval="60000"
            size="512"
            readOnly="true"/>

    <!--
        id：唯一標識，隨便寫，在同一個命名空間下保持唯一，使用動態代理之后要求和方法名保持一致
        parameterType：參數的類型，使用動態代理之后和方法的參數類型一致
    -->

    <!--基本查詢-->

    <!--查詢所有部門-->
    <select id="queryDepartmentList" parameterType="Department" resultType="Department">
        SELECT
        <include refid="DepartmentInfo"/>
        from tests.department
    </select>

    <!--根據部門ID，查詢單個部門信息-->
    <select id="queryDepartmentByDepartmentId" parameterType="Department" resultType="Department">
        SELECT <include refid="DepartmentInfo"></include> from tests.department where departmentId = #{departmentId}
    </select>

    <!--根據部門名稱，模糊查詢部門信息-->
    <select id="queryDepartmentListLikeByDepartmentName" parameterType="String" resultType="Department">
        SELECT <include refid="DepartmentInfo"></include> FROM tests.department WHERE departmentName LIKE
        CONCAT('%',#{departmentName},'%')
    </select>

    <!--添加一個部門-->
    <insert id="insertDepartmentList" parameterType="Department">
      INSERT INTO department (departmentName) VALUES (#{departmentName});
    </insert>

    <!--刪除一個部門-->
    <delete id="deleteDepartmentByDepartmentId" parameterType="Integer">
        delete from department where departmentId = #{departmentId}
    </delete>

    <!--修改一個部門，根據部門ID-->
    <update id="updateDepartentByDepartmentId" parameterType="Department">
        update department set departmentName= #{departmentName} where departmentId = #{departmentId}
    </update>

    <!--SQL代碼片段-->
    <sql id="DepartmentInfo">
        departmentId,departmentName
    </sql>

    <!--動態sql查詢-->

    <!--if   如果輸入了部門名稱，就按部門名稱來查詢，否則查詢所有部門-->
    <select id="queryDepartmentIf" parameterType="String" resultType="Department">
        SELECT
        <include refid="DepartmentInfo"/>
        from tests.department
        WHERE 1=1
        <if test="''!=departmentName and null != departmentName">
            AND departmentName LIKE CONCAT('%',#{departmentName},'%')
        </if>
    </select>

    <!--if和trim  如果有部門名稱和部門ID，查詢單個部門，否則查詢所有部門-->
    <!--trim 會自動刪除and和or，並且會自動識別標簽是否有返回值，有則加上前綴(prefix)和后綴(suffix)-->
    <select id="queryDepartmentIfAndTrim" parameterType="Department" resultType="Department">
        SELECT
        <include refid="DepartmentInfo"/>
        from tests.department
        <trim prefix="where" prefixOverrides="and |or">
            <if test="''!=departmentName and null != departmentName">
                AND departmentName = #{departmentName}
            </if>
            <if test="''!=departmentId and null != departmentId">
                AND departmentId = #{departmentId}
            </if>
        </trim>

    </select>

    <!--if+set 進行更新操作-->
    <update id="updateDepartmentIfAndSet" parameterType="Department">
        update department
        <set>
            <if test="''!=departmentName and null != departmentName">departmentName=#{departmentName},</if>
            <if test="''!=departmentId and null != departmentId">departmentId=#{departmentId}</if>
        </set>
        where departmentId = #{departmentId}
    </update>

    <!--foreach 根據部門ID查詢多條信息-->
    <!--
        item：集合中每個元素進行迭代的別名
        open：以什么開始
        close：以什么結束
        separator:以什么分隔
        collection：若入參為單參數，且參數類型是一個List的時候，collection屬性值為list
                    若入參為單參數，且參數類型是一個數組的時候，collection屬性值為array
                    若入參為多參數，就需要將他們封裝為一個Map進行處理
    -->
    <select id="queryDepartmentByArrayDepartmentId" parameterType="Department" resultType="Department">
        SELECT <include refid="DepartmentInfo"></include> from tests.department where departmentId in
      <foreach collection="array" item="departmentId" open="(" close=")" separator=",">
          ${departmentId}
      </foreach>
    </select>

    <!--List類型的foreach迭代-->
    <select id="queryDepartmentByListDepartmentId" parameterType="Department" resultType="Department">
        SELECT <include refid="DepartmentInfo"></include> from tests.department where departmentId in
        <foreach collection="list" item="departmentId" open="(" close=")" separator=",">
            ${departmentId}
        </foreach>
    </select>

</mapper>

單測

public class PracticeMapperTest {

    private static final Logger logger = LoggerFactory.getLogger(PracticeMapperTest.class);
    SqlSession sqlSession = MyBatisUtil.createSqlSession();

    /**
     * 查詢所有部門
     *
     * @throws IOException
     */
    @Test
    public void queryDepartmentList() throws IOException {
        //獲取mapper接口的對象
        List<Department> departments = sqlSession.getMapper(PracticeMapper.class).queryDepartmentList();
        for (Department department : departments) {
            System.out.println(department.toString());
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    /**
     * 根據部門ID，查詢單個部門信息
     */
    @Test
    public void queryDepartmentByDepartmentId(){
        Department department = sqlSession.getMapper(PracticeMapper.class).queryDepartmentByDepartmentId(5);
        System.out.println(department);
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    /**
     * 根據部門名稱，模糊查詢部門信息
     */
    @Test
    public void queryDepartmentListLikeByDepartmentName(){
        List<Department> list = sqlSession.getMapper(PracticeMapper.class).queryDepartmentListLikeByDepartmentName("氣");
        for(Department item:list){
            System.out.println(item);
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    /**
     * 添加一個部門
     */
    @Test
    public void insertDepartmentList(){
        Department department = new Department();
        department.setDepartmentName("卡牌部門");
        Integer integer = sqlSession.getMapper(PracticeMapper.class).insertDepartmentList(department);
        if(integer > 0){
            sqlSession.commit();//自動提交
        }else{
            sqlSession.rollback();//回滾
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    /**
     * 刪除一個部門
     */
    @Test
    public void deleteDepartmentByDepartmentId(){
        Integer integer = sqlSession.getMapper(PracticeMapper.class).deleteDepartmentByDepartmentId(11);
        if(integer > 0){
            sqlSession.commit();//自動提交
        }else{
            sqlSession.rollback();//回滾
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    /**
     * 修改一個部門，根據部門ID
     */
    @Test
    public void updateDepartentByDepartmentId(){
        Integer integer = sqlSession.getMapper(PracticeMapper.class).updateDepartentByDepartmentId( "靈氣部門",4);
        if(integer > 0){
            sqlSession.commit();//自動提交
        }else{
            sqlSession.rollback();//回滾
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    /**
     * 如果輸入了部門名稱，就按部門名稱來查詢，否則查詢所有部門
     */
    @Test
    public void queryDepartmentIf(){
        List<Department> list = sqlSession.getMapper(PracticeMapper.class).queryDepartmentIf("魔");
        for(Department item : list){
            System.out.println(item);
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    //where和if  如果有部門名稱和部門ID，查詢單個部門，否則查詢所有部門
    @Test
    public void queryDepartmentIfAndTrim(){
        Department department = new Department();
        department.setDepartmentName("靈氣部門");
        List<Department> list = sqlSession.getMapper(PracticeMapper.class).queryDepartmentIfAndTrim(department);
        for(Department item : list){
            System.out.println(item);
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    //if+set進行更新操作
    @Test
    public void updateDepartmentIfAndSet(){
        Department department = new Department();
        department.setDepartmentId(4);
        department.setDepartmentName("仙氣大陸");
        Integer integer = sqlSession.getMapper(PracticeMapper.class).updateDepartmentIfAndSet(department);
        if(integer > 0){
            sqlSession.commit();//自動提交
        }else{
            sqlSession.rollback();//回滾
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    //foreach 根據部門ID查詢多條信息
    @Test
    public void queryDepartmentByArrayDepartmentId(){
        Integer[] integers = {3,5,8};
        List<Department> departments = sqlSession.getMapper(PracticeMapper.class).queryDepartmentByArrayDepartmentId(integers);
        for(Department items: departments){
            System.out.println(items);
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

    //List類型的foreach迭代
    @Test
    public void queryDepartmentByListDepartmentId(){
        List<Integer> list = new ArrayList<Integer>();
        list.add(3);
        list.add(9);
        List<Department> departments = sqlSession.getMapper(PracticeMapper.class).queryDepartmentByListDepartmentId(list);
        for(Department items: departments){
            System.out.println(items);
        }
        MyBatisUtil.closeSqlSession(sqlSession);//關閉資源
    }

}

 

一對一

實體類

public class Department {

    private int departmentId;
    private String departmentName;

    public int getDepartmentId() {
        return departmentId;
    }

    public void setDepartmentId(int departmentId) {
        this.departmentId = departmentId;
    }

    public String getDepartmentName() {
        return departmentName;
    }

    public void setDepartmentName(String departmentName) {
        this.departmentName = departmentName;
    }

    public Department() {
    }

    public Department(int departmentId, String departmentName) {
        this.departmentId = departmentId;
        this.departmentName = departmentName;
    }

    @Override
    public String toString() {
        return "Department{" +
                "departmentId=" + departmentId +
                ", departmentName='" + departmentName + '\'' +
                '}';
    }
}

 

public class Employees {

    private int employeesId;
    private String employeesName;
    private int departmentId;
    private String employeesAddress;
    private Date employeesBirthday;   //java.sql.Date;
    private Department department;

    public Employees() {
    }

    public Employees(int employeesId, String employeesName, int departmentId, String employeesAddress, Date employeesBirthday, Department department) {
        this.employeesId = employeesId;
        this.employeesName = employeesName;
        this.departmentId = departmentId;
        this.employeesAddress = employeesAddress;
        this.employeesBirthday = employeesBirthday;
        this.department = department;
    }

    public int getEmployeesId() {
        return employeesId;
    }

    public void setEmployeesId(int employeesId) {
        this.employeesId = employeesId;
    }

    public String getEmployeesName() {
        return employeesName;
    }

    public void setEmployeesName(String employeesName) {
        this.employeesName = employeesName;
    }

    public int getDepartmentId() {
        return departmentId;
    }

    public void setDepartmentId(int departmentId) {
        this.departmentId = departmentId;
    }

    public String getEmployeesAddress() {
        return employeesAddress;
    }

    public void setEmployeesAddress(String employeesAddress) {
        this.employeesAddress = employeesAddress;
    }

    public Date getEmployeesBirthday() {
        return employeesBirthday;
    }

    public void setEmployeesBirthday(Date employeesBirthday) {
        this.employeesBirthday = employeesBirthday;
    }

    public Department getDepartment() {
        return department;
    }

    public void setDepartment(Department department) {
        this.department = department;
    }

    @Override
    public String toString() {
        return "Employees{" +
                "employeesId=" + employeesId +
                ", employeesName='" + employeesName + '\'' +
                ", departmentId=" + departmentId +
                ", employeesAddress='" + employeesAddress + '\'' +
                ", employeesBirthday=" + employeesBirthday +
                ", department=" + department +
                '}';
    }
}

Mapper

public Employees getEmployeesListByEmployeesId(@Param("employeesId")Integer employeesId);

Mapper.xml

    <resultMap id="employeesDepartmentList" type="Employees">
        <id property="employeesId" column="employeesId"/>
        <result property="employeesName" column="employeesName"/>
        <result property="employeesAddress" column="employeesAddress"/>
        <result property="employeesBirthday" column="employeesBirthday"/>
        <result property="departmentId" column="departmentId"/>
        <association property="department" javaType="Department">
            <id property="departmentId" column="departmentId"/>
            <result property="departmentName" column="departmentName"/>
        </association>
    </resultMap>
    <!--1對一查詢  查詢出員工id為2的員工信息和他的部門信息-->
    <select id="getEmployeesListByEmployeesId" resultMap="employeesDepartmentList" >
        select e.employeesId,e.employeesName,e.employeesAddress,e.employeesBirthday,e.departmentId,d.departmentName
        from employees e,department d
        where e.employeesId = #{employeesId} and e.departmentId = d.departmentId
    </select>

單側

    //1對一查詢  查詢出員工id為2的員工信息和他的部門信息
    @Test
    public void getEmployeesListByEmployeesId(){
        Integer integer = 3;
        Employees employees = sqlSession.getMapper(PracticeMapper.class).getEmployeesListByEmployeesId(integer);
        System.out.println(employees);
    }

 

一對多 

修改mapper

    public List<Employees> getEmployeesListByDepartmentId(@Param("departmentId")Integer departmentId);

 

修改mapper.xml

    <!--1對多查詢  根據部門ID查詢多此部門下的員工信息-->
    <select id="getEmployeesListByDepartmentId" resultMap="employeesDepartmentList">
        select e.employeesId,e.employeesName,e.employeesAddress,e.employeesBirthday,e.departmentId,d.departmentName
        from employees e,department d
        where e.departmentId = #{departmentId} and e.departmentId = d.departmentId
    </select>

單側

    //1對多查詢  根據部門ID查詢多此部門下的員工信息
    @Test
    public void getEmployeesListByDepartmentId(){
        Integer integer = 2;
        List<Employees> employees = sqlSession.getMapper(PracticeMapper.class).getEmployeesListByDepartmentId(integer);
        for(Employees item : employees){
            System.out.println(item);
        };
    }