MyBatis快速入门(简明浅析易懂)
发布时间：2020-12-14 14:44:52 所属栏目：Java 来源：网络整理
导读：一、MyBatis简介 MyBatis是支持普通SQL查询，存储过程和高级映射的优秀持久层框架。 MyBatis消除了几乎所有的JDBC代码和参数的手工设置以及对结果集的检索封装。 MyBatis可以使用简单的XML或注解用于配置和原始映射，将接口和Java的POJO（Plain Old Java Obj
|
一、MyBatis简介
MyBatis是支持普通SQL查询，存储过程和高级映射的优秀持久层框架。 MyBatis消除了几乎所有的JDBC代码和参数的手工设置以及对结果集的检索封装。 MyBatis可以使用简单的XML或注解用于配置和原始映射，将接口和Java的POJO（Plain Old Java Objects，普通的Java对象）映射成数据库中的记录. JDBC -> dbutils(自动封装) -> MyBatis -> Hibernate mybatis是将sql写在xml中，然后去访问数据库。 二、MyBatis快速入门 2.1.新建java项目 添加mybatis和mysql的驱动jar：mybatis-3.1.1.jar,mysql-connector-java-5.1.7-bin.jar 2.2.新建表
create database mybatis;
use mybatis;
create table users(id int primary key auto_increment,name varchar(20),age int);
insert into users (name,age) values('Tom',12);
insert into users (name,age) values('Jack',11);
2.3.添加mybatis的配置文件conf.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> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/mybatis" /> <property name="username" value="root" /> <property name="password" value="root" /> </dataSource> </environment> </environments> </configuration> 2.4.定义表对应的实体类
public class User {
private int id;
private String name;
private int age;
//get,set方法
}
2.5.定义操作users表的sql映射文件userMapper.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.atguigu.mybatis_test.test1.userMapper">
<select id="getUser" parameterType="int"
resultType="com.atguigu.mybatis_test.test1.User">
select * from users where id=#{id}
</select>
</mapper>
2.6.在conf.xml文件中注册userMapper.xml文件 <mappers> <mapper resource="com/atguigu/mybatis_test/test1/userMapper.xml"/> </mappers> 2.7.编写测试代码：执行定义的select语句
public class Test {
public static void main(String[] args) throws IOException {
String resource = "conf.xml";
//加载mybatis的配置文件（它也加载关联的映射文件）
Reader reader = Resources.getResourceAsReader(resource);
//构建sqlSession的工厂
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
//创建能执行映射文件中sql的sqlSession
SqlSession session = sessionFactory.openSession();
//映射sql的标识字符串
String statement = "com.atguigu.mybatis.bean.userMapper"+".selectUser";
//执行查询返回一个唯一user对象的sql
User user = session.selectOne(statement,1);
System.out.println(user);
}
}
三、操作users表的CRUD 3.1.xml的实现 3.1.1.定义sql映射xml文件：
<insert id="insertUser" parameterType="com.atguigu.ibatis.bean.User">
insert into users(name,age) values(#{name},#{age});
</insert>
<delete id="deleteUser" parameterType="int">
delete from users where id=#{id}
</delete>
<update id="updateUser" parameterType="com.atguigu.ibatis.bean.User">
update users set name=#{name},age=#{age} where id=#{id}
</update>
<select id="selectUser" parameterType="int" resultType="com.atguigu.ibatis.bean.User">
select * from users where id=#{id}
</select>
<select id="selectAllUsers" resultType="com.atguigu.ibatis.bean.User">
select * from users
</select>
3.1.2.在config.xml中注册这个映射文件 <mapper resource=" com/atguigu/ibatis/bean/userMapper.xml"/> 3.1.3.在dao中调用
public User getUserById(int id) {
SqlSession session = sessionFactory.openSession();
User user = session.selectOne(URI+".selectUser",id);
return user;
}
3.2.注解的实现 3.2.1.定义sql映射的接口
public interface UserMapper {
@Insert("insert into users(name,#{age})")
public int insertUser(User user);
@Delete("delete from users where id=#{id}")
public int deleteUserById(int id);
@Update("update users set name=#{name},age=#{age} where id=#{id}")
public int updateUser(User user);
@Select("select * from users where id=#{id}")
public User getUserById(int id);
@Select("select * from users")
public List<User> getAllUser();
}
3.2.2.在config中注册这个映射接口 <mapper class="com.atguigu.ibatis.crud.ano.UserMapper"/> 3.2.3.在dao中调用
public User getUserById(int id) {
SqlSession session = sessionFactory.openSession();
UserMapper mapper = session.getMapper(UserMapper.class);
User user = mapper.getUserById(id);
return user;
}
四、几个可以优化的地方 4.1.连接数据库的配置可以单独放在一个properties文件中。
## db.properties<br>
<properties resource="db.properties"/>
<property name="driver" value="${driver}" />
<property name="url" value="${url}" />
<property name="username" value="${username}" />
<property name="password" value="${password}" />
4.2.为实体类定义别名,简化sql映射xml文件中的引用 <typeAliases> <typeAlias type="com.atguigu.ibatis.bean.User" alias="_User"/> </typeAliases> 4.3.可以在src下加入log4j的配置文件,打印日志信息 1. 添加jar: log4j-1.2.16.jar 2.1. log4j.properties(方式一) log4j.properties， log4j.rootLogger=DEBUG,Console #Console log4j.appender.Console=org.apache.log4j.ConsoleAppender log4j.appender.Console.layout=org.apache.log4j.PatternLayout log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n log4j.logger.java.sql.ResultSet=INFO log4j.logger.org.apache=INFO log4j.logger.java.sql.Connection=DEBUG log4j.logger.java.sql.Statement=DEBUG log4j.logger.java.sql.PreparedStatement=DEBUG 2.2. log4j.xml(方式二)
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern"
value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) n" />
</layout>
</appender>
<logger name="java.sql">
<level value="debug" />
</logger>
<logger name="org.apache.ibatis">
<level value="debug" />
</logger>
<root>
<level value="debug" />
<appender-ref ref="STDOUT" />
</root>
</log4j:configuration>
五、解决字段名与实体类属性名不相同的冲突 5.1.准备表和字段
CREATE TABLE orders(
order_id INT PRIMARY KEY AUTO_INCREMENT,order_no VARCHAR(20),order_price FLOAT
);
INSERT INTO orders(order_no,order_price) VALUES('aaaa',23);
INSERT INTO orders(order_no,order_price) VALUES('bbbb',33);
INSERT INTO orders(order_no,order_price) VALUES('cccc',22);
5.2.定义实体类
public class Order {
private int id;
private String orderNo;
private float price;
}
5.3.实现getOrderById(id)的查询： 方式一: 通过在sql语句中定义别名
<select id="selectOrder" parameterType="int" resultType="_Order">
select order_id id,order_no orderNo,order_price price from orders where order_id=#{id}
</select>
方式二: 通过<resultMap>
<select id="selectOrderResultMap" parameterType="int" resultMap="orderResultMap">
select * from orders where order_id=#{id}
</select>
<resultMap type="_Order" id="orderResultMap">
<id property="id" column="order_id"/>
<result property="orderNo" column="order_no"/>
<result property="price" column="order_price"/>
</resultMap>
六、实现关联表查询 6.1.一对一关联 6.1.1.提出需求 根据班级id查询班级信息(带老师的信息) 6.1.2.创建表和数据
CREATE TABLE teacher(
t_id INT PRIMARY KEY AUTO_INCREMENT,t_name VARCHAR(20)
);
CREATE TABLE class(
c_id INT PRIMARY KEY AUTO_INCREMENT,c_name VARCHAR(20),teacher_id INT
);
ALTER TABLE class ADD CONSTRAINT fk_teacher_id FOREIGN KEY (teacher_id) REFERENCES teacher(t_id);
INSERT INTO teacher(t_name) VALUES('LS1');
INSERT INTO teacher(t_name) VALUES('LS2');
INSERT INTO class(c_name,teacher_id) VALUES('bj_a',1);
INSERT INTO class(c_name,teacher_id) VALUES('bj_b',2);
6.1.3.定义实体类：
public class Teacher {
private int id;
private String name;
}
public class Classes {
private int id;
private String name;
private Teacher teacher;
}
6.1.4.定义sql映射文件ClassMapper.xml
<!--
方式一: 嵌套结果: 使用嵌套结果映射来处理重复的联合结果的子集
SELECT * FROM class c,teacher t,student s WHERE c.teacher_id=t.t_id AND c.C_id=s.class_id AND c.c_id=1
-->
<select id="getClass3" parameterType="int" resultMap="ClassResultMap3">
select * from class c,student s where c.teacher_id=t.t_id and c.C_id=s.class_id and c.c_id=#{id}
</select>
<resultMap type="_Classes" id="ClassResultMap3">
<id property="id" column="c_id"/>
<result property="name" column="c_name"/>
<association property="teacher" column="teacher_id" javaType="_Teacher">
<id property="id" column="t_id"/>
<result property="name" column="t_name"/>
</association>
<!-- ofType指定students集合中的对象类型 -->
<collection property="students" ofType="_Student">
<id property="id" column="s_id"/>
<result property="name" column="s_name"/>
</collection>
</resultMap>
<!--
方式二：嵌套查询：通过执行另外一个SQL映射语句来返回预期的复杂类型
SELECT * FROM class WHERE c_id=1;
SELECT * FROM teacher WHERE t_id=1 //1 是上一个查询得到的teacher_id的值
SELECT * FROM student WHERE class_id=1 //1是第一个查询得到的c_id字段的值
-->
<select id="getClass4" parameterType="int" resultMap="ClassResultMap4">
select * from class where c_id=#{id}
</select>
<resultMap type="_Classes" id="ClassResultMap4">
<id property="id" column="c_id"/>
<result property="name" column="c_name"/>
<association property="teacher" column="teacher_id" javaType="_Teacher" select="getTeacher2"></association>
<collection property="students" ofType="_Student" column="c_id" select="getStudent"></collection>
</resultMap>
<select id="getTeacher2" parameterType="int" resultType="_Teacher">
SELECT t_id id,t_name name FROM teacher WHERE t_id=#{id}
</select>
<select id="getStudent" parameterType="int" resultType="_Student">
SELECT s_id id,s_name name FROM student WHERE class_id=#{id}
</select>
6.1.5.测试
@Test
public void testOO() {
SqlSession sqlSession = factory.openSession();
Classes c = sqlSession.selectOne("com.atguigu.day03_mybatis.test5.OOMapper.getClass",1);
System.out.println(c);
}
@Test
public void testOO2() {
SqlSession sqlSession = factory.openSession();
Classes c = sqlSession.selectOne("com.atguigu.day03_mybatis.test5.OOMapper.getClass2",1);
System.out.println(c);
}
6.2.一对多关联 6.2.1.提出需求 根据classId查询对应的班级信息,包括学生,老师 6.2.2.创建表和数据：
CREATE TABLE student(
s_id INT PRIMARY KEY AUTO_INCREMENT,s_name VARCHAR(20),class_id INT
);
INSERT INTO student(s_name,class_id) VALUES('xs_A',1);
INSERT INTO student(s_name,class_id) VALUES('xs_B',class_id) VALUES('xs_C',class_id) VALUES('xs_D',2);
INSERT INTO student(s_name,class_id) VALUES('xs_E',class_id) VALUES('xs_F',2);
6.2.3.定义实体类
public class Student {
private int id;
private String name;
}
public class Classes {
private int id;
private String name;
private Teacher teacher;
private List<Student> students;
}
6.2.4.定义sql映射文件ClassMapper.xml
<!--
方式一: 嵌套结果: 使用嵌套结果映射来处理重复的联合结果的子集
SELECT * FROM class c,s_name name FROM student WHERE class_id=#{id}
</select>
6.2.5.测试
@Test
public void testOM() {
SqlSession sqlSession = factory.openSession();
Classes c = sqlSession.selectOne("com.atguigu.day03_mybatis.test5.OOMapper.getClass3",1);
System.out.println(c);
}
@Test
public void testOM2() {
SqlSession sqlSession = factory.openSession();
Classes c = sqlSession.selectOne("com.atguigu.day03_mybatis.test5.OOMapper.getClass4",1);
System.out.println(c);
}
七、动态sql与模糊查询 7.1.需求 实现多条件查询用户(姓名模糊匹配,年龄在指定的最小值到最大值之间)。 7.2.准备数据库和表
create table d_user(
id int primary key auto_increment,name varchar(10),age int(3)
);
insert into d_user(name,12);
insert into d_user(name,age) values('Bob',13);
insert into d_user(name,18);
7.3.ConditionUser(查询条件实体类)
private String name;
private int minAge;
private int maxAge;
7.4.User表实体类 private int id; private String name; private int age; 7.5.userMapper.xml(映射文件)
<?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.atguigu.day03_mybatis.test6.userMapper">
<select id="getUser" parameterType="com.atguigu.day03_mybatis.test6.ConditionUser" resultType="com.atguigu.day03_mybatis.test6.User">
select * from d_user where age>=#{minAge} and age<=#{maxAge}
<if test='name!="%null%"'>and name like #{name}</if>
</select>
</mapper>
7.6.UserTest(测试)
public class UserTest {
public static void main(String[] args) throws IOException {
Reader reader = Resources.getResourceAsReader("conf.xml");
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
SqlSession sqlSession = sessionFactory.openSession();
String statement = "com.atguigu.day03_mybatis.test6.userMapper.getUser";
List<User> list = sqlSession.selectList(statement,new ConditionUser("%a%",1,12));
System.out.println(list);
}
}
MyBatis中可用的动态SQL标签 八、调用存储过程 8.1.提出需求 查询得到男性或女性的数量,如果传入的是0就女性否则是男性 8.2.准备数据库表和存储过程:
create table p_user(
id int primary key auto_increment,sex char(2)
);
insert into p_user(name,sex) values('A',"男");
insert into p_user(name,sex) values('B',"女");
insert into p_user(name,sex) values('C',"男");
#创建存储过程(查询得到男性或女性的数量,如果传入的是0就女性否则是男性)
DELIMITER $
CREATE PROCEDURE mybatis.ges_user_count(IN sex_id INT,OUT user_count INT)
BEGIN
IF sex_id=0 THEN
SELECT COUNT(*) FROM mybatis.p_user WHERE p_user.sex='女' INTO user_count;
ELSE
SELECT COUNT(*) FROM mybatis.p_user WHERE p_user.sex='男' INTO user_count;
END IF;
END
$
#调用存储过程
DELIMITER ;
SET @user_count = 0;
CALL mybatis.ges_user_count(1,@user_count);
SELECT @user_count;
8.3.创建表的实体类
public class User {
private String id;
private String name;
private String sex;
}
8.4.userMapper.xml <mapper namespace="com.atguigu.mybatis.test7.userMapper"> <!-- 查询得到男性或女性的数量,如果传入的是0就女性否则是男性 CALL mybatis.get_user_count(1,@user_count); --> <select id="getCount" statementType="CALLABLE" parameterMap="getCountMap"> call mybatis.get_user_count(?,?) </select> <parameterMap type="java.util.Map" id="getCountMap"> <parameter property="sex_id" mode="IN" jdbcType="INTEGER"/> <parameter property="user_count" mode="OUT" jdbcType="INTEGER"/> </parameterMap> </mapper> 8.5.测试
Map<String,Integer> paramMap = new HashMap<>();
paramMap.put("sex_id",0);
session.selectOne(statement,paramMap);
Integer userCount = paramMap.get("user_count");
System.out.println(userCount);
九、MyBatis缓存 9.1.理解mybatis缓存 正如大多数持久层框架一样，MyBatis 同样提供了一级缓存和二级缓存的支持 1.一级缓存: 基于PerpetualCache 的 HashMap本地缓存，其存储作用域为 Session，当 Session flush 或 close 之后，该Session中的所有 Cache 就将清空。 2. 二级缓存与一级缓存其机制相同，默认也是采用 PerpetualCache，HashMap存储，不同在于其存储作用域为 Mapper(Namespace)，并且可自定义存储源，如 Ehcache。 3. 对于缓存数据更新机制，当某一个作用域(一级缓存Session/二级缓存Namespaces)的进行了 C/U/D 操作后，默认该作用域下所有 select 中的缓存将被clear。 9.2.mybatis一级缓存 9.2.1.根据任务查询 根据id查询对应的用户记录对象。 9.2.2.准备数据库表和数据
CREATE TABLE c_user(
id INT PRIMARY KEY AUTO_INCREMENT,NAME VARCHAR(20),age INT
);
INSERT INTO c_user(NAME,age) VALUES('Tom',12);
INSERT INTO c_user(NAME,age) VALUES('Jack',11);
9.2.3.创建表的实体类
public class User implements Serializable{
private int id;
private String name;
private int age;
9.2.4.userMapper.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.atguigu.mybatis.test8.userMapper">
<select id="getUser" parameterType="int" resultType="_CUser">
select * from c_user where id=#{id}
</select>
<update id="updateUser" parameterType="_CUser">
update c_user set
name=#{name},age=#{age} where id=#{id}
</update>
</mapper>
9.2.5.测试
/*
* 一级缓存: 也就Session级的缓存(默认开启)
*/
@Test
public void testCache1() {
SqlSession session = MybatisUtils.getSession();
String statement = "com.atguigu.mybatis.test8.userMapper.getUser";
User user = session.selectOne(statement,1);
System.out.println(user);
/*
* 一级缓存默认就会被使用
*/
/*
user = session.selectOne(statement,1);
System.out.println(user);
*/
/*
1. 必须是同一个Session,如果session对象已经close()过了就不可能用了
*/
/*
session = MybatisUtils.getSession();
user = session.selectOne(statement,1);
System.out.println(user);
*/
/*
2. 查询条件是一样的
*/
/*
user = session.selectOne(statement,2);
System.out.println(user);
*/
/*
3. 没有执行过session.clearCache()清理缓存
*/
/*
session.clearCache();
user = session.selectOne(statement,2);
System.out.println(user);
*/
/*
4. 没有执行过增删改的操作(这些操作都会清理缓存)
*/
/*
session.update("com.atguigu.mybatis.test8.userMapper.updateUser",new User(2,"user",23));
user = session.selectOne(statement,2);
System.out.println(user);
*/
}
9.3.MyBatis二级缓存 9.3.1.添加一个<cache>在userMapper.xml中 <mapper namespace="com.atguigu.mybatis.test8.userMapper"> <cache/> 9.3.2.测试
/*
* 测试二级缓存
*/
@Test
public void testCache2() {
String statement = "com.atguigu.mybatis.test8.userMapper.getUser";
SqlSession session = MybatisUtils.getSession();
User user = session.selectOne(statement,1);
session.commit();
System.out.println("user="+user);
SqlSession session2 = MybatisUtils.getSession();
user = session2.selectOne(statement,1);
session.commit();
System.out.println("user2="+user);
}
9.3.3.补充说明 1. 映射语句文件中的所有select语句将会被缓存。 2. 映射语句文件中的所有insert，update和delete语句会刷新缓存。 3. 缓存会使用Least Recently Used（LRU，最近最少使用的）算法来收回。 4. 缓存会根据指定的时间间隔来刷新。 5. 缓存会存储1024个对象 <cache eviction="FIFO" //回收策略为先进先出 flushInterval="60000" //自动刷新时间60s size="512" //最多缓存512个引用对象 readOnly="true"/> //只读 十、Spring集成MyBatis 10.1.添加jar 【mybatis】 mybatis-3.2.0.jar 【spring】 spring-aop-3.2.0.RELEASE.jar 【MYSQL驱动包】 mysql-connector-java-5.0.4-bin.jar 10.2.数据库表 CREATE TABLE s_user( user_id INT AUTO_INCREMENT PRIMARY KEY,user_name VARCHAR(30),user_birthday DATE,user_salary DOUBLE ) 10.3.实体类：User
public class User {
private int id;
private String name;
private Date birthday;
private double salary;
//set,get方法
}
10.4.DAO接口: UserMapper (XXXMapper)
public interface UserMapper {
void save(User user);
void update(User user);
void delete(int id);
User findById(int id);
List<User> findAll();
}
10.5.SQL映射文件: userMapper.xml(与接口忽略大小写同名)
<?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.atguigu.mybatis.test9.UserMapper">
<resultMap type="User" id="userResult">
<result column="user_id" property="id"/>
<result column="user_name" property="name"/>
<result column="user_birthday" property="birthday"/>
<result column="user_salary" property="salary"/>
</resultMap>
<!-- 取得插入数据后的id -->
<insert id="save" keyColumn="user_id" keyProperty="id" useGeneratedKeys="true">
insert into s_user(user_name,user_birthday,user_salary)
values(#{name},#{birthday},#{salary})
</insert>
<update id="update">
update s_user
set user_name = #{name},user_birthday = #{birthday},user_salary = #{salary}
where user_id = #{id}
</update>
<delete id="delete">
delete from s_user
where user_id = #{id}
</delete>
<select id="findById" resultMap="userResult">
select *
from s_user
where user_id = #{id}
</select>
<select id="findAll" resultMap="userResult">
select *
from s_user
</select>
</mapper>
10.6.spring的配置文件: beans.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd"> <!-- 1. 数据源 : DriverManagerDataSource --> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/> <property name="username" value="root"/> <property name="password" value="root"/> </bean> <!-- 2. mybatis的SqlSession的工厂: SqlSessionFactoryBean dataSource / typeAliasesPackage --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource"/> <property name="typeAliasesPackage" value="com.atuigu.spring_mybatis2.domain"/> </bean> <!-- 3. mybatis自动扫描加载Sql映射文件 : MapperScannerConfigurer sqlSessionFactory / basePackage --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.atuigu.spring_mybatis2.mapper"/> <property name="sqlSessionFactory" ref="sqlSessionFactory"/> </bean> <!-- 4. 事务管理 : DataSourceTransactionManager --> <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"/> </bean> <!-- 5. 使用声明式事务 --> <tx:annotation-driven transaction-manager="txManager" /> </beans> 10.7.mybatis的配置文件: mybatis-config.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> <!-- Spring整合myBatis后，这个配置文件基本可以不要了--> <!-- 设置外部配置文件 --> <!-- 设置类别名 --> <!-- 设置数据库连接环境 --> <!-- 映射文件 --> </configuration> 10.8.测试
@RunWith(SpringJUnit4ClassRunner.class) //使用Springtest测试框架
@ContextConfiguration("/beans.xml") //加载配置
public class SMTest {
@Autowired //注入
private UserMapper userMapper;
@Test
public void save() {
User user = new User();
user.setBirthday(new Date());
user.setName("marry");
user.setSalary(300);
userMapper.save(user);
System.out.println(user.getId());
}
@Test
public void update() {
User user = userMapper.findById(2);
user.setSalary(2000);
userMapper.update(user);
}
@Test
public void delete() {
userMapper.delete(3);
}
@Test
public void findById() {
User user = userMapper.findById(1);
System.out.println(user);
}
@Test
public void findAll() {
List<User> users = userMapper.findAll();
System.out.println(users);
}
}
以上所述是小编给大家介绍的MyBatis快速入门(简明浅析易懂)，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对编程小技巧网站的支持！ （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
