Mybatis注解开发相关

一、项目构建

1、Java项目目录结构

2、在domain包下创建User实体类

package sun.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * @Classname User
 * @Description TODO
 * @Date 2020/9/13 14:07
 * @Created by Administrator
 */
public class User implements Serializable {
    private Integer id;
    private String username;
    private String address;
    private String sex;
    private Date birthday;

    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 String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", address='" + address + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                '}';
    }
}

User实体类

3、在dao包下创建UserDao接口

package sun.dao;

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 sun.domain.User;

import javax.jws.soap.SOAPBinding;
import java.util.List;

/**
 * @Classname UserDao
 * @Description TODO
 * @Date 2020/9/13 14:09
 * @Created by Administrator
 */
public interface UserDao {
    /**
     * 查询所有用户
     */
    @Select("select * from user")
    List<User> findAll();

    /**
     * 根据id查user
     */
    @Select("select * from user where id=#{id}")
    User findUserById(Integer id);

    /**
     * 模糊查询
     */
    @Select("select * from user where username like #{name}")
    List<User> findLike(String name);

    /**
     * 查询记录总数
     */
    @Select("select count(1) from user")
    int findTotal();

    /**
     * 添加新用户
     */
    @Insert("insert into user(username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})")
    void saveUser(User user);

    /**
     * 更新用户信息
     */
    @Update("update user set username=#{username},address=#{address},birthday=#{birthday},sex=#{sex} where id=#{id}")
    void updateUser(User user);

    /**
     * 删除用户
     */
    @Delete("delete from user where id=#{id}")
    void deleteUser(Integer id);
}

UserDao接口

4、在resource目录下创建SqlMapConfig.xml主配置文件

<?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>
    <properties resource="jdbcConfig.properties"></properties>

    <typeAliases>
        <package name="sun.domain"></package>
    </typeAliases>
    <!--配置环境-->
    <environments default="mysql">
        <!--配置mysql环境-->
        <environment id="mysql">
            <!--配置事务类型-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置数据库连接池-->
            <dataSource type="POOLED">
                <!--配置连接数据库基本信息-->
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <package name="sun.dao"></package>
    </mappers>
</configuration>

SqlMapConfig.xml

5、创建测试类

package sun.test;

import org.apache.ibatis.annotations.Select;
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.After;
import org.junit.Before;
import org.junit.Test;
import sun.dao.UserDao;
import sun.domain.User;

import java.io.InputStream;
import java.util.List;

/**
 * @Classname MybatisTest
 * @Description TODO
 * @Date 2020/9/13 14:57
 * @Created by Administrator
 */
public class MybatisTest {
    InputStream in;
    SqlSessionFactoryBuilder builder;
    SqlSessionFactory sessionFactory;
    SqlSession sqlSession;
    UserDao userDao;

    @Before
    public void init() throws Exception{
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        builder = new SqlSessionFactoryBuilder();
        sessionFactory = builder.build(in);
        sqlSession = sessionFactory.openSession();
        userDao = sqlSession.getMapper(UserDao.class);
    }
    @After
    public void destory() throws Exception{
        sqlSession.commit();
        sqlSession.close();
        in.close();
    }

    @Test
    public void findAllTest() throws Exception{
        List<User> users = userDao.findAll();
        for (User user : users) {
            System.out.println(user);
        }
    }

    @Test
    public void findOneTest() throws Exception{
        User user = userDao.findUserById(48);
        System.out.println(user);
    }

    @Test
    public void findLikeTest() throws Exception{
        List<User> users = userDao.findLike("%王%");
        for (User user : users) {
            System.out.println(user);
        }
    }

    @Test
    public void findTotalTest() throws Exception{
        int total = userDao.findTotal();
        System.out.println(total);
    }

    @Test
    public void saveUserTest() throws Exception{
        User user = new User();
        user.setUsername("kelvin");
        user.setAddress("安徽省宿州市");
        userDao.saveUser(user);
    }

    @Test
    public void updateTest() throws Exception{
        User user = new User();
        user.setId(49);
        user.setUsername("kelvin");
        user.setAddress("安徽省宿州市");
        user.setSex("男");
        userDao.updateUser(user);
    }

    @Test
    public void deleteTest(){
        userDao.deleteUser(50);
    }
}

测试类

二、构建实体类属性和数据库表字段对应关系

在接口方法中使用@Result来构建实体类属性和数据库表字段之间的关系，后面方法如果想要使用该关系可以使用@ResultMap进行使用。

package sun.dao;

import org.apache.ibatis.annotations.*;
import sun.domain.User;

import javax.jws.soap.SOAPBinding;
import java.util.List;

/**
 * @Classname UserDao
 * @Description TODO
 * @Date 2020/9/13 14:09
 * @Created by Administrator
 */
public interface UserDao {
    /**
     * 查询所有用户
     */
    @Select("select * from user")
    @Results(id="userMap",value={
            @Result(id=true,property = "user_id",column = "id"),
            @Result(property = "user_name",column = "username"),
            @Result(property = "user_sex",column = "sex"),
            @Result(property = "user_address",column = "address"),
            @Result(property = "user_birthday",column = "birthday"),
    })
    List<User> findAll();

    /**
     * 根据id查user
     */
    @Select("select * from user where id=#{id}")
//    @ResultMap(value = {"userMap"}) // 正规写法
    @ResultMap("userMap")  // 只有一个参数 简写
    User findUserById(Integer id);

    /**
     * 模糊查询
     */
    @Select("select * from user where username like #{name}")
    @ResultMap(value = {"userMap"})
    List<User> findLike(String name);

}

UserDao接口

三、一对一&一对多查询

创建一对一，一对多查询主要使用了@Result中的one属性和many属性。配置one或many中的select和fetchType即可。

Java项目目录结构

1、一对一

1）在domain下创建User和Account实体类

User类：

package sun.domain;

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

/**
 * @Classname User
 * @Description TODO
 * @Date 2020/9/13 14:07
 * @Created by Administrator
 */
public class User implements Serializable {
    private Integer user_id;
    private String user_name;
    private String user_address;
    private String user_sex;
    private Date user_birthday;
    private List<Account> accountList;

    public List<Account> getAccountList() {
        return accountList;
    }

    public void setAccountList(List<Account> accountList) {
        this.accountList = accountList;
    }

    public Integer getUser_id() {
        return user_id;
    }

    public void setUser_id(Integer user_id) {
        this.user_id = user_id;
    }

    public String getUser_name() {
        return user_name;
    }

    public void setUser_name(String user_name) {
        this.user_name = user_name;
    }

    public String getUser_address() {
        return user_address;
    }

    public void setUser_address(String user_address) {
        this.user_address = user_address;
    }

    public String getUser_sex() {
        return user_sex;
    }

    public void setUser_sex(String user_sex) {
        this.user_sex = user_sex;
    }

    public Date getUser_birthday() {
        return user_birthday;
    }

    public void setUser_birthday(Date user_birthday) {
        this.user_birthday = user_birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "user_id=" + user_id +
                ", user_name='" + user_name + '\'' +
                ", user_address='" + user_address + '\'' +
                ", user_sex='" + user_sex + '\'' +
                ", user_birthday=" + user_birthday +
                '}';
    }
}

User

Account类：

package sun.domain;

import java.io.Serializable;

/**
 * @Classname Account
 * @Description TODO
 * @Date 2020/9/14 8:50
 * @Created by Administrator
 */
public class Account implements Serializable {
    private Integer id;
    private Integer uid;
    private Double money;
    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Integer getId() {
        return id;
    }

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

    public Integer getUid() {
        return uid;
    }

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

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", uid=" + uid +
                ", money=" + money +
                '}';
    }
}

Account

2）在dao包下创建UserDao接口和AccountDao接口

UserDao接口：

package sun.dao;

import org.apache.ibatis.annotations.*;
import org.apache.ibatis.mapping.FetchType;
import sun.domain.User;

import javax.jws.soap.SOAPBinding;
import java.util.List;

/**
 * @Classname UserDao
 * @Description TODO
 * @Date 2020/9/13 14:09
 * @Created by Administrator
 */
public interface UserDao {
    /**
     * 查询所有用户
     */
    @Select("select * from user")
    @Results(id="userMap",value={
            @Result(id=true,property = "user_id",column = "id"),
            @Result(property = "user_name",column = "username"),
            @Result(property = "user_sex",column = "sex"),
            @Result(property = "user_address",column = "address"),
            @Result(property = "user_birthday",column = "birthday"),
            @Result(property = "accountList",column = "id",
                    many = @Many(select = "sun.dao.AccountDao.findAccountById",
                            fetchType = FetchType.LAZY))
    })
    List<User> findAll();

    /**
     * 根据id查user
     */
    @Select("select * from user where id=#{id}")
//    @ResultMap(value = {"userMap"}) // 正规写法
    @ResultMap("userMap")  // 只有一个参数 简写
    User findUserById(Integer id);

}

UserDao接口

Account接口：

package sun.dao;

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 org.apache.ibatis.mapping.FetchType;
import sun.domain.Account;

import java.util.List;

/**
 * @Classname AccountDao
 * @Description TODO
 * @Date 2020/9/14 8:52
 * @Created by Administrator
 */
public interface AccountDao {
    /**
     * 查询所有数据
     */
    @Select("select * from account")
    //配置多对一（一对一）查询
    @Results(id = "accountMap",value = {
            @Result(id = true,property = "id",column = "id"),
            @Result(property = "uid",column = "uid"),
            @Result(property = "money",column = "money"),
            @Result(property = "user",column = "uid",one = @One(select = "sun.dao.UserDao.findUserById",fetchType= FetchType.EAGER))
    })
    List<Account> findAll();

    /**
     * 根据id查user
     */
    @Select("select * from account where uid=#{id}")
    Account findAccountById(Integer id);

}

AccountDao接口

3）创建主配置文件

4）测试

package sun.test;

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.After;
import org.junit.Before;
import org.junit.Test;
import sun.dao.AccountDao;
import sun.domain.Account;
import sun.domain.User;

import java.io.InputStream;
import java.util.List;

/**
 * @Classname MybatisTest
 * @Description TODO
 * @Date 2020/9/13 14:57
 * @Created by Administrator
 */
public class MybatisTest2 {
    InputStream in;
    SqlSessionFactoryBuilder builder;
    SqlSessionFactory sessionFactory;
    SqlSession sqlSession;
    AccountDao accountDao;

    @Before
    public void init() throws Exception{
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        builder = new SqlSessionFactoryBuilder();
        sessionFactory = builder.build(in);
        sqlSession = sessionFactory.openSession();
        accountDao = sqlSession.getMapper(AccountDao.class);
    }
    @After
    public void destory() throws Exception{
        sqlSession.commit();
        sqlSession.close();
        in.close();
    }
    @Test
    public void findAll(){
        List<Account> all = accountDao.findAll();
        for (Account account : all) {
            System.out.println(account);
            System.out.println(account.getUser());
        }
    }
}

2、一对多

1）同上

2）同上

3）同上

4）测试类

package sun.test;

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.After;
import org.junit.Before;
import org.junit.Test;
import sun.dao.UserDao;
import sun.domain.User;

import java.io.InputStream;
import java.util.List;

/**
 * @Classname MybatisTest
 * @Description TODO
 * @Date 2020/9/13 14:57
 * @Created by Administrator
 */
public class MybatisTest {
    InputStream in;
    SqlSessionFactoryBuilder builder;
    SqlSessionFactory sessionFactory;
    SqlSession sqlSession;
    UserDao userDao;

    @Before
    public void init() throws Exception {
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        builder = new SqlSessionFactoryBuilder();
        sessionFactory = builder.build(in);
        sqlSession = sessionFactory.openSession();
        userDao = sqlSession.getMapper(UserDao.class);
    }

    @After
    public void destory() throws Exception {
        sqlSession.commit();
        sqlSession.close();
        in.close();
    }

    @Test
    public void findAllTest() throws Exception {
        List<User> users = userDao.findAll();
        for (User user : users) {
            System.out.println(user);
            System.out.println(user.getAccountList());
        }
    }

}

实体类属性和表字段对应关系、一对一、一对多查询及延迟加载均在@Result注解中配置。