MyBatis注解实现增删改查

pom.xml

 <dependencies>
        <!--mybatis坐标-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.4</version>
        </dependency>
        <!--mysql驱动坐标-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
            <scope>runtime</scope>
        </dependency>
        <!--单元测试坐标-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <!--            <scope>test</scope>-->
        </dependency>
 
 
    </dependencies>

User.java

//编写实体类 对应映射User表
public class User implements Serializable {
    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;
    private List<Order> orderList;
//    保存用户角色列表
    private List<Role> roleList;
 
    public User() {
    }
 
    public User(String username, Date birthday, String sex, String address) {
        this.username = username;
        this.birthday = birthday;
        this.sex = sex;
        this.address = address;
    }
 
    public User(Integer id, String username, Date birthday, String sex, String address, List<Order> orderList) {
        this.id = id;
        this.username = username;
        this.birthday = birthday;
        this.sex = sex;
        this.address = address;
        this.orderList = orderList ;
    }
 
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                ", orderList=" + orderList +
                ", roleList=" + roleList +
                '}';
    }
 
    public List<Role> getRoleList() {
        return roleList;
    }
 
    public void setRoleList(List<Role> roleList) {
        this.roleList = roleList;
    }
 
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public String getUsername() {
        return username;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    public Date getBirthday() {
        return birthday;
    }
 
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
 
    public String getSex() {
        return sex;
    }
 
    public void setSex(String sex) {
        this.sex = sex;
    }
 
    public String getAddress() {
        return address;
    }
 
    public void setAddress(String address) {
        this.address = address;
    }
 
    public List<Order> getOrderList() {
        return orderList;
    }
 
    public void setOrderList(List<Order> orderList) {
        this.orderList = orderList;
    }
}

Role.java

package com.qiku.popo;
 
public class Role {
    private Integer id;
    private String roleNmae;
    private String roleDesc;
 
 
    public Role() {
    }
 
    @Override
    public String toString() {
        return "Role{" +
                "id=" + id +
                ", roleNmae='" + roleNmae + '\'' +
                ", roleDesc='" + roleDesc + '\'' +
                '}';
    }
 
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public String getRoleNmae() {
        return roleNmae;
    }
 
    public void setRoleNmae(String roleNmae) {
        this.roleNmae = roleNmae;
    }
 
    public String getRoleDesc() {
        return roleDesc;
    }
 
    public void setRoleDesc(String roleDesc) {
        this.roleDesc = roleDesc;
    }
}

Order.java

package com.qiku.popo;
 
import java.io.Serializable;
import java.util.Date;
 
public class Order implements Serializable {
    private Integer id;
    private Date orderTime;
    private double money;
 
    // 表示当前订单属于哪个用户
    private User user;
 
 
    public Order() {
    }
 
    public Order(Integer id, Date orderTime, double money, User user) {
        this.id = id;
        this.orderTime = orderTime;
        this.money = money;
        this.user = user;
    }
 
 
    @Override
    public String toString() {
        return "Order{" +
                "id=" + id +
                ", orderTime=" + orderTime +
                ", money=" + money +
                ", user=" + user +
                '}';
    }
 
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public Date getOrderTime() {
        return orderTime;
    }
 
    public void setOrderTime(Date orderTime) {
        this.orderTime = orderTime;
    }
 
    public double getMoney() {
        return money;
    }
 
    public void setMoney(double money) {
        this.money = money;
    }
 
    public User getUser() {
        return user;
    }
 
    public void setUser(User user) {
        this.user = user;
    }
}

UserMapper.java

package com.qiku.mapper;
 
 
import com.qiku.popo.Order;
import com.qiku.popo.User;
import org.apache.ibatis.annotations.*;
 
import java.util.List;
 
@CacheNamespace
public interface UserMapper {
 
    @Insert("insert into user (username , birthday , sex , address)" + " values (#{username} , #{birthday} , #{sex} , #{address})")
    public void addUser(User user);
 
    @Delete("delete from user where id = #{id}")
    public void deleteUser(Integer id);
 
    @Update("update user set address = #{address} where id = #{id}")
    public void updateUser(User user);
 
    @Select("select * from user")
    public List<User> findAllUser();
 
    @Select("select * from user where id = #{id}")
    public User findUserById(Integer id);
 
    @Select("select * from user")
    @Results({
            @Result(id = true , column = "id" ,property = "id"),
            @Result(column = "username" , property = "username"),
            @Result(column = "birthday" , property = "birthday"),
            @Result(column = "sex" , property = "sex"),
            @Result(column = "address" , property = "address"),
            @Result(property = "orderList" , javaType = List.class , column = "id" , many = @Many(select = "com.qiku.mapper.OrderMapper.findOrderByUid"))
    })
    public List<User> findAllUserWithOrder();
 
 
 
//    查询所有用户 及其 角色信息
    @Select("select * from user")
    @Results({
            @Result(id = true , column = "id" ,property = "id"),
            @Result(column = "username" , property = "username"),
            @Result(column = "birthday" , property = "birthday"),
            @Result(column = "sex" , property = "sex"),
            @Result(column = "address" , property = "address"),
            @Result(property = "roleList" , javaType = List.class , column = "id" , many = @Many(select = "com.qiku.mapper.RoleMapper.findRoleByUid"))
    })
    public List<User> findAllUserWithRole();
 
 
}

RoleMapper.java

public interface RoleMapper {
 
    @Select("select * from sys_role r LEFT JOIN sys_user_role ur on r.id = ur.roleid WHERE ur.userid = #{userId}")
    public List<Role> findRoleByUid(Integer userId);
}

OrderMapper.java

public interface OrderMapper {
 
//    查询所有订单 及 订单的用户信息
    @Select("select * from orders ")
    @Results({
            @Result(id = true , column = "id" ,property = "id"),
            @Result(column = "ordertime" , property = "orderTime"),
            @Result(column = "total" , property = "money"),
            @Result(property = "user" , javaType = User.class , column = "uid" ,
                    one = @One(select = "com.qiku.mapper.UserMapper.findUserById" ,
                            fetchType = FetchType.EAGER))
    })
    public List<Order> findAllOrderWithUser();
 
//    根据用户id（uid）查询订单信息
    @Select("select * from orders where uid = #{uid}")
    @Results({
            @Result(id = true , column = "id" , property = "id"),
            @Result(column = "ordertime" , property = "orderTime"),
            @Result(column = "total" , property = "money")
    })
    public List<Order> findOrderByUid(Integer uid);
}

核心配置文件

SqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!--    加载外部文件-->
    <properties resource="jdbc.properties"/>
<!--    控制台打印sql语句-->
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
        <!--所有方法都会延迟加载-->
<!--        <setting name="lazyLoadTriggerMethods" value="toString()"/>-->
 
<!--        因为cacheEnabled的取值默认就为true，所以这一步可以省略不配置。
		    为true代表开启二级缓存；为false代表不开启二级缓存。
-->
        <setting name="cacheEnabled" value="true"/>
    </settings>
    <!-- 配置数据库环境-->
    <environments default="mysql01">
        <environment id="mysql01">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
 
<!--    加载映射文件-->
    <mappers>
<!--        resource ; 属性加载的是 接口的xml文件-->
<!--        <mapper resource="com/qiku/mapper/UserMapper.xml"/>-->
<!--        <mapper resource="com/qiku/mapper/OrderMapper.xml"/>-->
 
 
<!--        class 属性加载的是接口的全路径名-->
<!--        <mapper class="com.qiku.mapper.UserMapper"/>-->
<!--       指定加载包的位置, 推荐-->
        <package name="com.qiku.mapper"/>
    </mappers>
 
</configuration>

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mydb03
jdbc.username=root
jdbc.password=123456

测试类

UserMapperTEst.java

package com.qiku.test;
 
import com.qiku.mapper.UserMapper;
import com.qiku.popo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
 
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
 
public class UserMapperTEst {
 
    @Test
    public void testAddUser() throws IOException {
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession = factory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 
        User user = new User("关羽" , new Date() , "男" , "蜀国" );
        mapper.addUser(user);
        sqlSession.commit();
 
    }
 
    @Test
    public void testUpdateUser() throws IOException {
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession = factory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 
        User user = new User("关羽" , new Date() , "男" , "河东" );
        user.setId(4);
        mapper.updateUser(user);
        sqlSession.commit();
 
    }
 
    @Test
    public void testFindAllUser() throws IOException {
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession = factory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.findAllUser();
        System.out.println(userList);
 
    }
 
    @Test
    public void testDeleteUser() throws IOException {
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession = factory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 
 
        mapper.deleteUser(3);
        sqlSession.commit();
 
    }
 
 
    @Test
    public void testFindAllUserWithOrder() throws IOException {
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession = factory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 
        List<User> userList = mapper.findAllUserWithOrder();
        for (User u : userList){
            System.out.println(u);
        }
 
    }
 
 
 
    @Test
    public void testFindAllUserWithRole() throws IOException {
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession = factory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 
        List<User> userList = mapper.findAllUserWithRole();
        for (User u : userList){
            System.out.println(u);
        }
 
    }
 
}

OrderMapperTest.java

public class OrderMapperTest {
 
    @Test
    public void testFindAllOrderWithUser() throws IOException {
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession = factory.openSession();
        OrderMapper mapper = sqlSession.getMapper(OrderMapper.class);
 
        List<Order> orderList = mapper.findAllOrderWithUser();
        for (Order o : orderList){
            System.out.println(o);
        }
 
    }
}

LocalCacheTest02.java

public class LocalCacheTest02 {
    @Test
    public void localCacheTest01() throws IOException {
 
        InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resource);
        SqlSession sqlSession1 = factory.openSession();
        UserMapper mapper1 = sqlSession1.getMapper(UserMapper.class);
        User userById1 = mapper1.findUserById(1);
        System.out.println("====第一次查询====:" + userById1);
 
        //将结果存入二级缓存
        sqlSession1.commit();
        SqlSession sqlSession2 = factory.openSession();
        UserMapper mapper2 = sqlSession2.getMapper(UserMapper.class);
        User userById2 = mapper2.findUserById(1);
        System.out.println("====第二次查询====:" + userById2);
    }
 
}

使用注解实现复杂映射开发

我们在映射文件中通过配置 <resultMap>、<association>、<collection> 来实现复杂关系映射。
使用注解开发后，我们可以使用 @Results、@Result，@One、@Many 注解组合完成复杂关系的配置。