MyBatis-xml版本

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添加依赖

<dependencies><!--mysql驱动--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><!--mybatis--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.2</version></dependency><!--测试工具--><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>
<!--扫描包，读取配置文件-->
<build><resources><resource><directory>src/main/java</directory><includes><include>**/*.properties</include><include>**/*.xml</include></includes><filtering>true</filtering></resource><resource><directory>src/main/resources</directory><includes><include>**/*.properties</include><include>**/*.xml</include></includes><filtering>true</filtering></resource></resources>
</build>

resources目录下编写配置文件

• db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test?useSSL&useUnicode=true&charsetEncoding=UTF-8
username=root
password=123

• log4j.properties

# 输出DEBUG级别的日志到console和file
log4j.rootLogger=DEBUG,console,file
#输出到控制台的相关设置
log4j.appender.console = org.apache.log4j.ConsoleAppender
log4j.appender.console.Target = System.out
log4j.appender.console.Threshold = DEBUG
log4j.appender.console.layout = org.apache.log4j.PatternLayout
# log4j.appender.console.layout.ConversionPattern = [%c]-%m%n
log4j.appender.console.layout.ConversionPattern=%5p [%t] - %m%n
#输出到文件的相关设置
log4j.appender.file = org.apache.log4j.RollingFileAppender
# 不追加写入：log4j.appender.file.Append = false
# 输出位置
log4j.appender.file.File = ./log/log.log
# 文件最大容量，满了会生成新的文件
log4j.appender.file.MaxFileSize = 10mb
log4j.appender.file.Threshold = DEBUG
log4j.appender.file.layout = org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern = [%p][%d{yyyy-MM-dd HH:mm:ss}][%c]%m%n
#日志输出级别
log4j.logger.org.mybatis = DEBUG
log4j.logger.java.sql = DEBUG
log4j.logger.java.sql.Statement = DEBUG
log4j.logger.java.sql.ResultSet = DEBUG
log4j.logger.java.sql.PreparedStatement = DEBUG

• mybatis-config.xml

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd" >
<configuration><!--引入外部配置文件--><properties resource="db.properties"><!--可以添加属性，遇到相同属性，外部资源优先级高于这里--><property name="addr" value="bj"/></properties><settings><!--设置日志实现：STDOUT_LOGGING标准日志工厂-->
<!--        <setting name="logImpl" value="STDOUT_LOGGING"/>--><setting name="logImpl" value="LOG4J"/><!--开启全局缓存（二级），默认是true--><setting name="cacheEnabled" value="true"/></settings><!--别名设置--><typeAliases><!--自定义类的别名--><typeAlias type="org.example.pojo.User" alias="User"/><!--定义包下类的别名：默认是类名（建议首字母小写），要自定义别名可以在类名上加注解：@Alias("别名")--><package name="org.example.pojo"/></typeAliases><!--配置环境：default设置使用哪套环境--><environments default="prd"><environment id="dev"><!--设置事务类型--><transactionManager type="JDBC"></transactionManager><!--设置连接池--><dataSource type="POOLED"><property name="driver" value="com.mysql.jdbc.Driver"/><property name="username" value="root"/><property name="password" value="123"/><property name="url" value="jdbc:mysql://localhost:3306/test?useSSL&amp;useUnicode=true&amp;charsetEncoding=UTF-8"/></dataSource></environment><environment id="prd"><transactionManager type="JDBC"></transactionManager><dataSource type="POOLED"><property name="driver" value="${driver}"/><property name="username" value="${username}"/><property name="password" value="${password}"/><property name="url" value="${url}"/></dataSource></environment></environments><!--注册mapper.xml--><mappers><mapper resource="org/example/dao/UserMapper.xml"/></mappers>
</configuration>

实体类

//@Alias("user")
public class User implements Serializable {private Integer id;private String username;private String password;// getter、setter、tostring、有参构造、无参构造
}

mapper接口

public interface UserMapper {// xml实现List<User> getUsers();// 多参数情况下用注解@Param("占位名")声明User getUser(@Param("user_name") String username,@Param("pass_word") String password);User getUserById(Integer id);int insertUser(User user);int insertUserBatch(@Param("userList") List<User> userList);// 常用map做参数int insertUserAsMap(Map<String,Object> map);int updateUserById(User user);int deleteUserById(Integer id);int deleteUserByIds(Integer[] id);// 注解实现@Select("select * from user")List<User> getUsers2();
}

UserMapper.xml

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="org.example.dao.UserMapper"><!--在当前mapper.xml文件中使用二级缓存，实体类必须序列化--><!--会话提交或关闭后，数据会存入二级缓存--><cache/><resultMap id="userMap" type="org.example.pojo.User"><!--主键用id标签--><id column="id" property="id"/><!--普通字段用result标签--><result column="username" property="username"/><result column="password" property="password"/><!--对象属性配置，引用其他mapper.xml中配置好的resultMap，实现关联查询-->
<!--        <association property="user" resultMap="userMap"/>--><!--一对多--><!--<collection property="userList" ofType="user"><id column="id" property="id"/><result column="username" property="username"/><result column="password" property="password"/></collection>--></resultMap><select id="getUsers" resultMap="userMap">select * from user<!--特殊符号处理：< > & ' "--><!--<![CDATA[select * from user where id < 10]]>--></select><select id="getUser" resultMap="userMap">select * from user<where><if test="user_name != null and user_name != ''">and username like concat('%',#{user_name},'%')</if><if test="pass_word != null and pass_word != ''">and password = #{pass_word}</if><!--choose when otherwise类似switch case default--><!--<choose><when test="user_name != null and user_name != ''">and username like concat('%',#{user_name},'%')</when><when test="pass_word != null and pass_word != ''">and password = #{pass_word}</when><otherwise>and id = -1</otherwise></choose>--></where></select><select id="getUserById" parameterType="java.lang.Integer" resultType="org.example.pojo.User">select * from user where id = #{id}</select><!--对象参数可以直接解构，useGeneratedKeys返回生成的主键，返回到keyProperty指定的属性中--><insert id="insertUser" keyProperty="id" useGeneratedKeys="true">insert into user (id,username,password) values(#{id},#{username},#{password})</insert><!--批量新增--><insert id="insertUserBatch">insert into user (id,username,password) values<foreach collection="userList" item="user" separator=",">(#{user.id},#{user.username},#{user.password})</foreach></insert><!--通过map自定义占位符的命名，万能参数类型--><insert id="insertUserAsMap" parameterType="java.util.Map">insert into user (username,password) values(#{name},#{pwd})</insert><update id="updateUserById" parameterType="org.example.pojo.User">update user<set><!--set标签可以去除多余的逗号--><if test="username != null and username != ''">username = #{username},</if><if test="password != null and password != ''">password = #{password},</if></set><where><if test="id != null">and id = #{id}</if></where></update><delete id="deleteUserById" parameterType="java.lang.Integer">delete from user where id = #{id}</delete><delete id="deleteUserByIds">delete from user where id in<!--delete from user where id in ( ? , ? )--><foreach collection="array" item="id" separator="," open="(" close=")">#{id}</foreach></delete>
</mapper>

测试类

public class Test01 {private SqlSession sqlSession;@Beforepublic void before(){SqlSessionFactory sqlSessionFactory;try {InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);} catch (IOException e) {throw new RuntimeException(e);}sqlSession =  sqlSessionFactory.openSession();System.out.println("@Before在测试方法执行前执行，可以在此处获取sqlSession");}@Afterpublic void after(){// DML语句需要提交事务sqlSession.commit();sqlSession.close();System.out.println("@After在测试方法完成后执行，可以在此处提交事务，关闭资源");}@Testpublic void test01() {UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
//        System.out.println(userMapper.getUserById(-3));
//        User user = new User(null,"zhaoliu", "12345");
//        System.out.println(userMapper.insertUser(user));
//        System.out.println(user.getId());
//        List<User> userList = new ArrayList<>();
//        userList.add(new User(6,"66","666"));
//        userList.add(new User(7,"77","777"));
//        System.out.println(userMapper.insertUserBatch(userList));
//        System.out.println(userMapper.updateUserById(new User(5, "zhao", "12345")));
//        System.out.println(userMapper.deleteUserById(-4));
//        System.out.println(userMapper.deleteUserByIds(new Integer[]{6,7}));
//        Map<String,Object> map = new HashMap<String, Object>();
//        map.put("name","chenqi");
//        map.put("pwd",1234);
//        System.out.println(userMapper.insertUserAsMap(map));
//        System.out.println(userMapper.getUser("lisi","12345"));
//        System.out.println(userMapper.getUsers());System.out.println(userMapper.getUsers2());}
}