Mybatis使用实现类
项目结构
配置文件
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pom.xml
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.xiaoge</groupId> <artifactId>mybatisDAO</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <dependencies> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.5</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.13</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency> </dependencies> </project>
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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> <!--配置环境--> <environments default="mysql"> <!--配置mysql环境--> <environment id="mysql"> <!--配置事务--> <transactionManager type="JDBC"></transactionManager> <!--配置连接池--> <dataSource type="POOLED"> <property name="driver" value="com.mysql.cj.jdbc.Driver" /> <property name="url" value="jdbc:mysql://127.0.0.1:3306/eesy_mybatis" /> <property name="username" value="root" /> <property name="password" value="123456" /> </dataSource> </environment> </environments> <!--配置映射文件的位置--> <mappers> <mapper resource="com/xiaoge/dao/userDao.xml"></mapper> </mappers> </configuration>
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userDao.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="com.xiaoge.dao.UserDao"> <!--查询所有--> <select id="findAll" resultType="com.xiaoge.domain.User"> select * from user </select> <!--保存用户--> <insert id="saveUser" parameterType="com.xiaoge.domain.User"> <!-- 配置插入操作后, 获取插入数据的id --> <!-- keyColumn: 对应的数据库字段id --> <!-- keyProperty: 对应的实体类属性值id --> <!-- order: after是后做这件事 before是先做这件事 --> <selectKey keyProperty="id" keyColumn="id" resultType="java.lang.Integer" order="AFTER"> select last_insert_id(); </selectKey> insert into user(username, address, sex, birthday) value(#{username}, #{address}, #{sex}, #{birthday}) </insert> <!--更新用户--> <update id="updateUser" parameterType="com.xiaoge.domain.User"> update user set username = #{username}, address = #{address}, sex = #{sex}, birthday = #{birthday} where id = #{id} </update> <!--删除用户 这个参数是(基本类型, 或基本类型的包装类时), 而且只有一个参数, 这里#{占位符} 占位符可以随便写 --> <delete id="deleteUser" parameterType="java.lang.Integer"> delete from user where id = #{id} </delete> <!--查询条记录信息--> <select id="findById" parameterType="java.lang.Integer" resultType="com.xiaoge.domain.User"> select * from user where id = #{id} </select> <!--根据用户名模糊查询--> <select id="findByUsername" parameterType="java.lang.String" resultType="com.xiaoge.domain.User"> select * from user where username like #{username} </select> <!--查询总用户数量--> <select id="findTotal" resultType="java.lang.Integer"> select count(*) from user </select> </mapper>
实体类
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User
package com.xiaoge.domain; import java.util.Date; /** * @Author: 潇哥 * @DateTime: 2020/3/4 下午4:03 * @Description: TODO */ public class User { 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 + '}'; } }
持久层接口
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UserDao
package com.xiaoge.dao; import com.xiaoge.domain.User; import java.util.List; /** * @Author: 潇哥 * @DateTime: 2020/3/4 下午4:19 * @Description: 用户的持久层接口 */ public interface UserDao { /** * 查询所有用户 * @return */ public List<User> findAll(); /** * 保存用户 * @param user */ public void saveUser(User user); /** * 修改用户信息 * @param user */ public void updateUser(User user); /** * 删除用户 * @param userId */ public void deleteUser(Integer userId); /** * 查询该用户信息 * @param userId * @return */ public User findById(Integer userId); /** * 根据用户名模糊查询用户信息 * @param username * @return */ public List<User> findByUsername(String username); /** * 查询总用户数量 * @return */ public Integer findTotal(); }
持久层实现类
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UserDaoImpl
package com.xiaoge.dao.impl; import com.xiaoge.dao.UserDao; import com.xiaoge.domain.User; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import java.util.List; /** * @Author: 潇哥 * @DateTime: 2020/3/8 下午4:42 * @Description: 持久层实现类 */ public class UserDaoImpl implements UserDao { private SqlSessionFactory factory; public UserDaoImpl(SqlSessionFactory factory) { this.factory = factory; } @Override public List<User> findAll() { // 1. 根据factory获取SqlSession对象 SqlSession session = factory.openSession(); // 2. 调用SqlSession中的方法实现查询列表 List<User> users = session.selectList("com.xiaoge.dao.UserDao.findAll");// 参数是能获取的配置信息的key // 3. 释放资源 session.close(); return users; } @Override public void saveUser(User user) { // 1. 根据factory获取SqlSesssion对象 SqlSession session = factory.openSession(); // 2. 调用SqlSession中的方法实现保存 session.insert("com.xiaoge.dao.UserDao.saveUser", user); // 3. 提交事务 session.commit(); // 4. 释放资源 session.close(); } @Override public void updateUser(User user) { // 1. 根据factory获取SqlSesssion对象 SqlSession session = factory.openSession(); // 2. 调用SqlSession中的方法实现保存 session.update("com.xiaoge.dao.UserDao.updateUser", user); // 3. 提交事务 session.commit(); // 4. 释放资源 session.close(); } @Override public void deleteUser(Integer userId) { // 1. 根据factory获取SqlSesssion对象 SqlSession session = factory.openSession(); // 2. 调用SqlSession中的方法实现保存 session.delete("com.xiaoge.dao.UserDao.deleteUser", userId); // 3. 提交事务 session.commit(); // 4. 释放资源 session.close(); } @Override public User findById(Integer userId) { // 1. 根据factory获取SqlSesssion对象 SqlSession session = factory.openSession(); // 2. 调用SqlSession中的方法实现保存 User user = session.selectOne("com.xiaoge.dao.UserDao.findById", userId); // 3. 释放资源 session.close(); return user; } @Override public List<User> findByUsername(String username) { // 1. 根据factory获取SqlSesssion对象 SqlSession session = factory.openSession(); // 2. 调用SqlSession中的方法实现保存 List<User> users = session.selectList("com.xiaoge.dao.UserDao.findByUsername", username); // 3. 释放资源 session.close(); return users; } @Override public Integer findTotal() { // 1. 根据factory获取SqlSesssion对象 SqlSession session = factory.openSession(); // 2. 调用SqlSession中的方法实现保存 Integer count = session.selectOne("com.xiaoge.dao.UserDao.findTotal"); // 3. 释放资源 session.close(); return count; } }
测试持久层接口方法
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MybatisTest
package com.xiaoge.test; import com.xiaoge.dao.UserDao; import com.xiaoge.dao.impl.UserDaoImpl; import com.xiaoge.domain.User; import org.apache.ibatis.io.Resources; 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 java.io.IOException; import java.io.InputStream; import java.util.Date; import java.util.List; /** * @Author: 潇哥 * @DateTime: 2020/3/4 下午4:22 * @Description: 测试mybatis的crud操作 */ public class MybatisTest { private InputStream is; private UserDao userDao; /** * 初始化 获取代理对象 */ @Before // 用于在测试方法之前执行 public void init() throws IOException { // 1. 加载配置文件 is = Resources.getResourceAsStream("SqlMapConfig.xml"); // 2. 获取SqlSessionFactory SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); SqlSessionFactory factory = builder.build(is); // 3. 使用工厂对象, 创建dao对象 userDao = new UserDaoImpl(factory); } @After // 用与在测试方法之后执行 public void destroy() throws IOException { if (is != null) { is.close(); } } /** * 测试查询所有用户信息 * @throws IOException */ @Test public void findAllTest() throws IOException { // 1. 遍历获取所有的用户 List<User> users = userDao.findAll(); for (User user : users) { System.out.println(user); } // 运行结果 User{id=41, username='老王', address='北京', sex='男', birthday=Wed Feb 28 07:47:08 CST 2018} User{id=42, username='小二王', address='北京金燕龙', sex='女', birthday=Sat Mar 03 05:09:37 CST 2018} User{id=43, username='小二王', address='北京金燕龙', sex='女', birthday=Mon Mar 05 01:34:34 CST 2018} User{id=46, username='老王', address='北京', sex='男', birthday=Thu Mar 08 07:37:26 CST 2018} User{id=48, username='小马宝莉', address='北京修正', sex='女', birthday=Fri Mar 09 01:44:00 CST 2018} User{id=53, username='啸哥', address='北京四合院', sex='男', birthday=Fri Mar 06 13:10:42 CST 2020} User{id=54, username='李四 last insertid', address='北京', sex='男', birthday=Fri Mar 06 14:26:40 CST 2020} User{id=55, username='王五 last insertid', address='北京', sex='男', birthday=Fri Mar 06 15:17:43 CST 2020} User{id=56, username='李六 last insertid', address='北京', sex='男', birthday=Fri Mar 06 18:47:48 CST 2020} User{id=57, username='李六 last insertid', address='北京', sex='男', birthday=Fri Mar 06 19:11:40 CST 2020} } /** * 测试保存用户 */ @Test public void saveTest() throws IOException { // 1. 创建User User user = new User(); // 2. 封装User user.setUsername("李七 last insertid"); user.setAddress("北京"); user.setBirthday(new Date()); user.setSex("男"); System.out.println("保存操作之前: " + user); // 3. 执行添加方法 userDao.saveUser(user); System.out.println("保存操作之后: " + user); // 运行结果 保存操作之前: User{id=null, username='李白 last insertid', address='北京', sex='男', birthday=Wed Mar 11 18:17:19 CST 2020} 保存操作之后: User{id=59, username='李白 last insertid', address='北京', sex='男', birthday=Wed Mar 11 18:17:19 CST 2020} } /** * 测试修改用户信息 */ @Test public void updateTest() { // 1. 创建User User user = new User(); // 2. 封装User user.setId(58); user.setUsername("啸哥"); user.setAddress("北京四合院"); user.setBirthday(new Date()); user.setSex("男"); // 3. 执行方法 userDao.updateUser(user); } /** * 测试删除用户信息 */ @Test public void deleteTest() { // 1. 执行删除方法 userDao.deleteUser(58); } /** * 测试查询用户信息 */ @Test public void findOneTest() { // 1. 执行删除方法 User user = userDao.findById(53); System.out.println(user); // 运行结果 User{id=53, username='啸哥', address='北京四合院', sex='男', birthday=Fri Mar 06 13:10:42 CST 2020} } /** * 测试模糊查询操作 ---> 由于mybatis不能用%号 只能在调用的时候给%号 */ @Test public void findByUsernameTest() { // 1. 执行模糊查询方法 List<User> users = userDao.findByUsername("%王%"); for (User user : users) { System.out.println(user); } // 运行结果 User{id=41, username='老王', address='北京', sex='男', birthday=Wed Feb 28 07:47:08 CST 2018} User{id=42, username='小二王', address='北京金燕龙', sex='女', birthday=Sat Mar 03 05:09:37 CST 2018} User{id=43, username='小二王', address='北京金燕龙', sex='女', birthday=Mon Mar 05 01:34:34 CST 2018} User{id=46, username='老王', address='北京', sex='男', birthday=Thu Mar 08 07:37:26 CST 2018} User{id=55, username='王五 last insertid', address='北京', sex='男', birthday=Fri Mar 06 15:17:43 CST 2020} } /** * 测试查询用户总数量 */ @Test public void findTotalTest() { // 1. 执行查询用户总数量方法 Integer total = userDao.findTotal(); System.out.println(total); // 运行结果 11 } }