一、mybaties的使用
a、通過SqlSessionFactory獲得 SqlSession 的實例。
b、SqlSession 包含了面向數據庫執行 SQL 命令所需的方法。通過 SqlSession 實例來執行已映射的 SQL 語句。
思路
核心配置(mybaties-config)——》映射(mapper)——》SqlSessionFactory——》SqlSession
配置數據源
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>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="org/mybatis/example/BlogMapper.xml"/>
</mappers>
</configuration>
映射器(mappers)
BlogMapper.mapper
<?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="org.mybatis.example.BlogMapper">
<select id="selectBlog" resultType="Blog">
select * from Blog where id = #{id}
</select>
</mapper>
構建 SqlSessionFactory
test.java
String resource = "org/mybatis/example/mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession session = sqlSessionFactory.openSession();
BlogMapper mapper = session.getMapper(BlogMapper.class);
Blog blog = mapper.selectBlog(101);
//Blog blog = (Blog) session.selectOne("org.mybatis.example.BlogMapper.selectBlog", 101);
二、springJdbc的使用
思路
Dao——》配置——》applicationContext容器
數據模型
Student.java ——
public class Student {
private Integer age;
private String name;
private Integer id;
public void setAge(Integer age) {
this.age = age;
}
public Integer getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getId() {
return id;
}
}
Dao
StudentDAO.java——
public interface StudentDAO {
public void setDataSource(DataSource ds);
public void create(String name, Integer age);
public Student getStudent(Integer id);
public List<Student> listStudents();
public void delete(Integer id);
public void update(Integer id, Integer age);
}
StudentJDBCTemplate.java——
public class StudentJDBCTemplate implements StudentDAO {
private DataSource dataSource;
private JdbcTemplate jdbcTemplateObject;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
this.jdbcTemplateObject = new JdbcTemplate(dataSource);
}
public void create(String name, Integer age) {
String SQL = "insert into Student (name, age) values (?, ?)";
jdbcTemplateObject.update( SQL, name, age);
return;
}
public Student getStudent(Integer id) {
String SQL = "select * from Student where id = ?";
Student student = jdbcTemplateObject.queryForObject(SQL, new Object[]{id}, new StudentMapper());
return student;
}
public List<Student> listStudents() {
String SQL = "select * from Student";
List <Student> students = jdbcTemplateObject.query(SQL, new StudentMapper());
return students;
}
public void delete(Integer id){
String SQL = "delete from Student where id = ?";
jdbcTemplateObject.update(SQL, id);
return;
}
public void update(Integer id, Integer age){
String SQL = "update Student set age = ? where id = ?";
jdbcTemplateObject.update(SQL, age, id);
return;
}
}
配置數據源
Beans.xml ——bean
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd ">
<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/TEST"/>
<property name="username" value="root"/>
<property name="password" value="password"/>
</bean>
<bean id="studentJDBCTemplate" class="com.tutorialspoint.StudentJDBCTemplate">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>
ApplicationContext 容器
MainApp.java——
public class MainApp {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
StudentJDBCTemplate studentJDBCTemplate = (StudentJDBCTemplate)context.getBean("studentJDBCTemplate");
List<Student> students = studentJDBCTemplate.listStudents();
studentJDBCTemplate.update(2, 20);
Student student = studentJDBCTemplate.getStudent(2);
}
}
整合demo1
搭建項目
【src】中創建 4 個空包:
- cn.wmyskxz.dao
(放置 DAO 數據交互層處理類)
- cn.wmyskxz.mapper
(放置 Mapper 代理接口)
- cn.wmyskxz.pojo
(放置 Java 實體類)
- cn.wmyskxz.test
(放置測試類)
【config】用於放置各種資源配置文件:
- 【config / mybatis】
“SqlMapConfig.xml” : MyBatis 全局配置文件
- 【config / spring】
“applicationContext.xml” : Spring 資源配置文件
- 【config / sqlmap】
“UserMapper.xml” : Mapper 映射文件。
- 【config】
“db.properties” :用於數據庫連接
“log4j.properties”:日誌系統參數設置
引入依賴 jar 包
在【WEB-INF】文件夾下的【lib】文件夾中放置上面列舉的 jar 包,然後添加依賴
a、MyBatis 的包(MyBatis 3.4.6)
b、Spring 的 jar 包(Spring 4.3.15)
c、MyBatis 與 Spring 的整合 jar 包(mybatis-spring 1.3.2)
d、mysql-connector-java-5.1.21.jar
e、junit-4.12.jar
編寫 Spring 配置文件
a、頭部的信息就是聲明 xml 文檔配置標籤的規則的限制與規範。
b、“context:property-placeholder” 配置是用於讀取工程中的靜態屬性文件
c、配置了一個名爲 “dataSrouce” 的 bean 的信息,實際上是連接數據庫的數據源。
d、設置 sqlSessionFactory 的 bean 實現類爲 MyBatis 與 Spring 整合 jar 包中的 SqlSessionFactoryBean 類
<?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:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 加載配置文件 -->
<context:property-placeholder location="classpath:db.properties"/>
<!-- 配置數據源 -->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
<!-- sqlSessionFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 加載 MyBatis 的配置文件 -->
<property name="configLocation" value="mybatis/SqlMapConfig.xml"/>
<!-- 數據源 -->
<property name="dataSource" ref="dataSource"/>
</bean>
</beans>
編寫 MyBatis 配置文件
a、通過 settings 配置了一些延遲加載和緩存的開關信息
b、在 typeAliases 中設置了一個 package 的別名掃描路徑,在該路徑下的 Java 實體類都可以擁有一個別名(即首字母小寫的類名)
c、在 mappers 配置中,使用 mapper 標籤配置了即將要加載的 Mapper 映射文件的資源路徑
d、有了 Spring 託管數據源,在 MyBatis 配置文件中僅僅需要關注性能化配置。
MyBatis 的全局配置文件 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>
<!-- settings -->
<settings>
<!-- 打開延遲加載的開關 -->
<setting name="lazyLoadingEnabled" value="true"/>
<!-- 將積極加載改爲消極加載(即按需加載) -->
<setting name="aggressiveLazyLoading" value="false"/>
<!-- 打開全局緩存開關(二級緩存)默認值就是 true -->
<setting name="cacheEnabled" value="true"/>
</settings>
<!-- 別名定義 -->
<typeAliases>
<package name="cn.wmyskxz.pojo"/>
</typeAliases>
<!-- 加載映射文件 -->
<mappers>
<!-- 通過 resource 方法一次加載一個映射文件 -->
<mapper resource="sqlmap/UserMapper.xml"/>
<!-- 批量加載mapper -->
<package name="cn.wmyskxz.mapper"/>
</mappers>
</configuration>
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="test">
<select id="findUserById" parameterType="_int" resultType="user">
SELECT * FROM USER WHERE id = #{id}
</select>
</mapper>
Dao
UserDAOImpl
a、SqlSessionDaoSupport 類是 MyBatis 與 Spring 整合的 jar 包中提供的
b、在該類中已經包含了 sqlSessionFactory 對象作爲其成員變量,而且對外提供 get 和 set 方法
package cn.wmyskxz.dao;
import cn.wmyskxz.pojo.User;
import org.apache.ibatis.session.SqlSession;
import org.mybatis.spring.support.SqlSessionDaoSupport;
public class UserDAOImpl extends SqlSessionDaoSupport implements UserDAO {
@Override
public User findUserById(int id) throws Exception {
// 繼承 SqlSessionDaoSupport 類,通過 this.getSqlSession() 得到 sqlSession
SqlSession sqlSession = this.getSqlSession();
User user = sqlSession.selectOne("test.findUserById", id);
return user;
}
}
測試
package cn.wmyskxz.test;
import cn.wmyskxz.dao.UserDAO;
import cn.wmyskxz.pojo.User;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class UserServiceTest {
private ApplicationContext applicationContext;
// 在執行測試方法之前首先獲取 Spring 配置文件對象
// 註解@Before在執行本類所有測試方法之前先調用這個方法
@Before
public void setup() throws Exception {
applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
}
@Test
public void testFindUserById() throws Exception {
// 通過配置資源對象獲取 userDAO 對象
UserDAO userDAO = (UserDAO) applicationContext.getBean("userDAO");
// 調用 UserDAO 的方法
User user = userDAO.findUserById(1);
// 輸出用戶信息
System.out.println(user.getId() + ":" + user.getUsername());
}
}
整合demo2
mybatis配置文件
SqlMapconfig.xml
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 定義 別名 -->
<typeAliases>
<!-- 單個別名的定義 alias:別名,type:別名映射的類型 -->
<!-- <typeAlias type="com.hust.mybatis.po.User" alias="user"/> -->
<!-- 批量別名定義 指定包路徑,別名默認爲類名(首字母小寫或大寫) -->
<package name="com.hust.springmybatis.po"/>
</typeAliases>
<mappers>
<!-- 通過resource引用mapper的映射文件 -->
<mapper resource="sqlmap/User.xml" />
<mapper resource="mapper/UserMapper.xml" />
</mappers>
</configuration>
applicationContext.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:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd">
<!-- 配置數據源 -->
<context:property-placeholder location="classpath:db.properties"/>
<!-- 如果是用額外的配置文件 -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" 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>
<property name="maxActive" value="10"></property>
<property name="maxIdle" value="5"></property>
</bean>
<!-- SqlSessionFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 數據源 -->
<property name="dataSource" ref="dataSource"></property>
<!-- mybatis配置文件 -->
<property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"></property>
</bean>
<bean id="userDao" class="com.hust.springmybatis.dao.UserDaoImpl">
<property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
</bean>
<!-- MapperFactoryBean:用於生成mapper代理對象 -->
<!-- <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
<property name="mapperInterface" value="com.hust.springmybatis.mapper.UserMapper"></property>
<property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
</bean> -->
<!-- MapperScannerConfigurer:mapper的掃描器,將包下邊的mapper接口自動創建代理對象
自動創建到spring容器中,bean的id是mapper的類名(首字母小寫)
-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 配置掃描包路徑, 如果要掃描多個包,中間使用半角逗好隔開 -->
<property name="basePackage" value="com.hust.springmybatis.mapper"></property>
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
</bean>
</beans>
開發dao
dao接口
user.xml
測試