八、調用存儲過程
8.1. 提出需求:
查詢得到男性或女性的數量, 如果傳入的是0就女性否則是男性
8.2. 準備數據庫表和存儲過程:
create table p_user(
id int primary key auto_increment,
name varchar(10),
sex char(2)
);
insert into p_user(name,sex) values('趙英龍',"男");
insert into p_user(name,sex) values('楊帆',"男");
insert into p_user(name,sex) values('王爽',"女");
#創建存儲過程(查詢得到男性或女性的數量, 如果傳入的是0就女性否則是男性)
DELIMITER $
CREATE PROCEDURE mybatis.get_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
$
#調用存儲過程
DELIMITER ;
SET @user_count = 0;
CALL mybatis.get_user_count(1, @user_count);
SELECT @user_count;
8.3. 創建表的實體類
public class User {
private String id;
private String name;
private String sex;
}
8.4 創建保存輸入參數和輸出參數的實體類
package com.vo;
public class ProcedurePOJO {
private int sex;
private int userCount;
public int getUserCount() {
return userCount;
}
public void setUserCount(int userCount) {
this.userCount = userCount;
}
public int getSex() {
return sex;
}
public void setSex(int sex) {
this.sex = sex;
}
}
8.5. userMapper.xml
<mapper namespace="com.po.userMapper">
<!--調用完畢後返回值回自動回填到pojo中的userCount屬性裏-->
<select id="getCount" statementType="CALLABLE" parameterType="com.vo.ProcedurePOJO">
{call get_user_count(
#{sex,mode=IN,jdbcType=INTEGER},
#{userCount,mode=OUT,jdbcType=INTEGER}
)}
</select>
</mapper>
statementType取值可以是STATEMENT,PREPARED 或 CALLABLE 的一種。這會讓 MyBatis 使用選擇使用 Statement,PreparedStatement 或 CallableStatement。默認值:PREPARED。
8.5. 測試調用:
public void executeProcedure() {
try {
String statement = "com.po.userMapper.getCount";
ProcedurePOJO procedurePOJO = new ProcedurePOJO();
procedurePOJO.setSex(0);
sqlSession.selectOne(statement, procedurePOJO);
System.out.println(procedurePOJO.getUserCount());
} finally {
SessionFactoryUtil.closeSqlSession(sqlSession);
}
}
九、Mybatis緩存
9.1. 理解MyBatis緩存
正如大多數持久層框架一樣,MyBatis 同樣提供了一級緩存和二級緩存的支持
1.一級緩存: 基於PerpetualCache 的 HashMap本地緩存,其存儲作用域爲Session,當Session flush 或 close之後,該Session中的所有 Cache 就將清空。
2. 二級緩存與一級緩存其機制相同,默認也是採用 PerpetualCache,HashMap存儲,不同在於其存儲作用域爲Mapper(Namespace),並且可自定義存儲源,如 Ehcache。
3. 對於緩存數據更新機制,當某一個作用域(一級緩存Session/二級緩存Namespaces)的進行了 C/U/D 操作後,默認該作用域下所有 select 中的緩存將被clear。
9.2. Mybatis一級緩存
1) 提出需求:
根據id查詢對應的用戶記錄對象
2). 準備數據庫表和數據
CREATE TABLE c_user(
id INT PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(20),
age INT
);
insert into c_user(name, age) values('趙英龍', 22);
insert into c_user(name, age) values('楊帆', 23);
3). 創建表的實體類
public class User implements Serializable{
private int id;
private String name;
private int age;
}
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">
<!-- namespace 是該mapper文件的一個唯一表示 -->
<mapper namespace="com.po.userMapper">
<select id="getUser" parameterType="int" resultType="User">
select * from c_user where id=#{id}
</select>
<update id="updateUser" parameterType="User">
update c_user set
name=#{name}, age=#{age} where id=#{id}
</update>
</mapper>
5). 測試:
public User testCache() {
User user = null;
String statement = "com.po.userMapper.getUser";
try {
user = sqlSession.selectOne(statement, 1);
System.out.println(user);
System.out.println("****************************");
user = sqlSession.selectOne(statement, 1);
System.out.println(user);
} finally {
SessionFactoryUtil.closeSqlSession(sqlSession);
}
return user;
}
public void testCache1() {
User user = null;
User user2 = null;
String statement = "com.po.userMapper.getUser";
String statement2 = "com.po.userMapper.updateUser";
try {
user = sqlSession.selectOne(statement, 1);
user2 = sqlSession.selectOne(statement, 2);
System.out.println(user);
User updatedUser = new User();
updatedUser.setId(1);
updatedUser.setName("趙小龍");
updatedUser.setAge(30);
sqlSession.update(statement2,updatedUser);
System.out.println("*****************************");
user2 = sqlSession.selectOne(statement, 2);
System.out.println(user2);
} finally {
sqlSession.close();
}
}
9.3. Mybatis二級緩存
Mapper(namespace)級別的緩存
1). 添加一個<cache>在userMapper.xml中
<mapper namespace="com.vo.userMapper">
<cache/>
2). 測試
@Override
public User getUserById(Integer userid) {
User user = null;
String statement = "com.po.userMapper.getUser";
try {
user = sqlSession.selectOne(statement, userid);
} finally {
SessionFactoryUtil.closeSqlSession(sqlSession);
}
return user;
}
public static void main(String[] args) {
UserDaoImpl dao = new UserDaoImpl();
User user = dao.getUserById(1);
System.out.println(user);
System.out.println("**********************");
UserDaoImpl dao2 = new UserDaoImpl();
User user2 = dao2.getUserById(1);
System.out.println(user2);
}
注意:
1.必須關閉session二級緩存才生效,關閉的時候把session中的數據保存到二級緩存中
2.User類必須實現Serializable接口
3). 補充說明
1. 映射語句文件中的所有select語句將會被緩存。
2. 映射語句文件中的所有insert,update和delete語句會刷新緩存。
3. 緩存會使用Least Recently Used(LRU,最近最少使用的)算法來收回。
4. 緩存會根據指定的時間間隔來刷新。
5. 緩存會存儲1024個對象
<cache
eviction="FIFO"
flushInterval="60000"
size="512"
readOnly="true"/>
十、spring集成mybatis
10.1. 添加Jar包
【mybatis】
mybatis-3.2.0.jar
mybatis-spring-1.1.1.jar
log4j-1.2.17.jar
【spring】
spring-aop-3.2.0.RELEASE.jar
spring-beans-3.2.0.RELEASE.jar
spring-context-3.2.0.RELEASE.jar
spring-core-3.2.0.RELEASE.jar
spring-expression-3.2.0.RELEASE.jar
spring-jdbc-3.2.0.RELEASE.jar
spring-test-3.2.4.RELEASE.jar
spring-tx-3.2.0.RELEASE.jar
aopalliance-1.0.jar
cglib-nodep-2.2.3.jar
commons-logging-1.1.1.jar
【MYSQL驅動包】
mysql-connector-java-5.0.4-bin.jar
10.2. 數據庫表
CREATE TABLE s_user(
user_id INT AUTO_INCREMENT PRIMARY KEY,
user_name VARCHAR(30),
user_birthday DATE,
user_salary DOUBLE
)
10.3. 實體類: 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 {
public void save(User user);
public void update(User user);
public void delete(int id);
public User findById(int id);
public List<User> findAll();
}
10.5. SQL映射文件: userMapper.xml(與接口忽略大小寫同名)
<?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">
<!—namespace 一定要和接口的類全名一致-->
<mapper namespace="com.lanqiao.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>
<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">
<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>
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="typeAliasesPackage" value="com.atuigu.spring_mybatis2.domain"/>
</bean>
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.atuigu.spring_mybatis2.mapper"/>
<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>
<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>
<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>
</configuration>
10.8. 測試
@RunWith(SpringJUnit4ClassRunner.class) //使用Springtest測試框架
@ContextConfiguration("/beans.xml") //加載配置
public class SMTest {
@Autowired //注入
private UserMapper userMapper;
@Test
publicvoid save() {
User user = new User();
user.setBirthday(new Date());
user.setName("marry");
user.setSalary(300);
userMapper.save(user);
System.out.println(user.getId());
}
@Test
publicvoid update() {
User user = userMapper.findById(2);
user.setSalary(2000);
userMapper.update(user);
}
@Test
publicvoid delete() {
userMapper.delete(3);
}
@Test
publicvoid findById() {
User user = userMapper.findById(1);
System.out.println(user);
}
@Test
publicvoid findAll() {
List<User> users = userMapper.findAll();
System.out.println(users);
}
}