Spring的学习

标签：http Spring void springframework 学习 org import public

1.Spring

简介：

Spring框架是由于软件开发的复杂性而创建的。Spring使用的是基本的JavaBean来完成以前只可能由EJB完成的事情。然而，Spring的用途不仅仅限于服务器端的开发。从简单性、可测试性和松耦合性角度而言，绝大部分Java应用都可以从Spring中受益。

优点：

组成：

1.1 spring官方中文文档

https://www.docs4dev.com/docs/zh/spring-framework/5.1.3.RELEASE/reference/data-access.html

2.IOC理论推导

userDao --> userDaoImpl

userService-->userServiceImpl

我们之前的业务中，用户的需求可能会影响我们原来的代码，我们需要根据用户的需求去修改原来的代码！如果程序的代码量十分的大，修改一次的成本代价十分昂贵

我们使用一个set接口实现

private userDao userDao ;
//利用set进行动态实现值的注入
public void setUserDao(userDao userDao) {
    this.userDao = userDao;
}

3.IOC的本质

控制反转是一种通过描述（xml或注解）并通过第三方去生产或者获取特定对象的方式。在spring中实现控制反转的是ioc容器，其中实现方法是依赖注入。

4.Hello---Spring

编写一个类

package com.pojo;

public class Hello {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void show(){
        System.out.println("Hello"+name);
    }

    @Override
    public String toString() {
        return "Hello{" +
                "name='" + name + '\'' +
                '}';
    }
}

配置xml文件

<?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.xsd">

    <!-- 使用spring 创建-->
    <bean id="hello" class="com.pojo.Hello">
        <property name="name" value="gukeyang"/>
    </bean>

</beans>

测试的进行

import com.pojo.Hello;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class beanstest {
    public static void main(String[] args) {
        //获取spring的上下文对象
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        //我们的对象都在spring中管理，我们要使用，直接从外面取出来就可以了
        Hello hello = (Hello) context.getBean("hello");

        System.out.println(hello.toString());
    }
}

5.IOC创建对象方式

总结：在配置文件加载的时候，容器中管理的对象就已经初始化了。

6.spring配置说明

别名

<alias name="user" alias="sadas"/>

bean的配置

<!--
id:bean的唯一标识符，也就是相当于我们学的类型名
class:bean 对象所对应的全限定名：包名+类型
name也是别名，而且可以取多个别名
-->
<bean id="userT" class="com.kuang.pojo.UserT" name="user2">
    <property name ="name" value ="西部开源"/>
</bean>

import的说明

7.DI依赖注入环境

package com.pojo;

import java.util.*;

public class Student {
    private String name;
    private Address address;
    private String[] books;
    private List<String> hobby;

    private Map<String,String> card;
    private Set<String> games;
    private Properties info;
    private String wife;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public String[] getBooks() {
        return books;
    }

    public void setBooks(String[] books) {
        this.books = books;
    }

    public List<String> getHobby() {
        return hobby;
    }

    public void setHobby(List<String> hobby) {
        this.hobby = hobby;
    }

    public Map<String, String> getCard() {
        return card;
    }

    public void setCard(Map<String, String> card) {
        this.card = card;
    }

    public Set<String> getGames() {
        return games;
    }

    public void setGames(Set<String> games) {
        this.games = games;
    }

    public Properties getInfo() {
        return info;
    }

    public void setInfo(Properties info) {
        this.info = info;
    }

    public String getWife() {
        return wife;
    }

    public void setWife(String wife) {
        this.wife = wife;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", address=" + address +
                ", books=" + Arrays.toString(books) +
                ", hobby=" + hobby +
                ", card=" + card +
                ", games=" + games +
                ", info=" + info +
                ", wife='" + wife + '\'' +
                '}';
    }
}

package com.pojo;

public class Address {
    private String address;

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

<bean id="address" class="com.pojo.Address"/>
    <bean id="student" class="com.pojo.Student">
<!--        普通注入-->
        <property name="name" value="谷科阳"/>
<!--       bean注入-->
        <property name="address" ref="address"/>
<!--        数组注入-->
        <property name="books">
            <array>
                <value>红楼梦</value>
                <value>西游记</value>
                <value>水浒传</value>
                <value>三国演义</value>
            </array>
        </property>
<!--list-->
        <property name="hobby">
            <list>
                <value>唱</value>
                <value>跳</value>
                <value>rap</value>
            </list>
        </property>
<!--map-->
        <property name="card">
            <map>
                <entry key="1" value="a"/>
                <entry key="2" value="b"/>
                <entry key="3" value="c"/>
                <entry key="4" value="d"/>
            </map>
        </property>

        <property name="games">
            <set>
                <value>lol</value>
                <value>coc</value>
            </set>
        </property>

        <property name="wife">
            <null/>
        </property>

        <property name="info">
            <props>
                <prop key="学号">20211544113</prop>
                <prop key="性别">男</prop>
                <prop key="姓名">谷科阳</prop>
            </props>
        </property>

    </bean>

测试test

一：得到name
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");

Student student = (Student) context.getBean("student");

System.out.println(student.getName());
二：得到student对象的值
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");

Student student = (Student) context.getBean("student");

System.out.println(student.toString());

8.c命名和p命名注入

xmlns:p="http://www.springframework.org/schema/p"

<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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean name="classic" class="com.example.ExampleBean">
        <property name="email" value="[emailprotected]"/>
    </bean>

    <bean name="p-namespace" class="com.example.ExampleBean"
        p:email="[emailprotected]"/>
</beans>

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:c="http://www.springframework.org/schema/c"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="thingOne" class="x.y.ThingTwo"/>
<bean id="thingTwo" class="x.y.ThingThree"/>

<!-- traditional declaration -->
<bean id="thingOne" class="x.y.ThingOne">
    <constructor-arg ref="thingTwo"/>
    <constructor-arg ref="thingThree"/>
    <constructor-arg value="[emailprotected]"/>
</bean>

<!-- c-namespace declaration -->
<bean id="thingOne" class="x.y.ThingOne" c:thingTwo-ref="thingTwo" c:thingThree-ref="thingThree" c:email="[emailprotected]"/>
</beans>

9.bean的作用域

单例

原型

10.自动装配bean

自动配置是spring满足bean依赖的一种方式
Spring会在上下文中自动寻找，并自动会给bean装配属性

在spring的三种装配方式

1.在xml中显示的配置

2.在java中显示的配置

3.隐式的装配bean

小结：

byname的时候，需要保证所有的bean的id唯一，并且这个bean需要和自动注入的属性的set方法的值一致；

bytype的时候，需要保证所有的bean的class唯一，并且这个bean需要和自动注入的属性的类型一致；

11.注解实现装配

1.导入约束

2.配置注解的支持

<?xml versinotallow="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">

    <context:annotation-config/>

</beans>

package com.pojo;

public class dog {
    public void shout() {
        System.out.println("汪汪汪!");

    }
}

package com.pojo;

public class cat {
    public void shout(){
        System.out.println("喵喵喵！");
    }
}

package com.pojo;

import org.springframework.beans.factory.annotation.Autowired;

public class people {
    @Autowired
    private cat cat;
    @Autowired
    private dog dog;
    private String name;

    public com.pojo.cat getCat() {
        return cat;
    }

    public void setCat(com.pojo.cat cat) {
        this.cat = cat;
    }

    public com.pojo.dog getDog() {
        return dog;
    }

    public void setDog(com.pojo.dog dog) {
        this.dog = dog;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "people{" +
                "cat=" + cat +
                ", dog=" + dog +
                ", name='" + name + '\'' +
                '}';
    }
}

<?xml versinotallow="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">

    <context:annotation-config/>

    <bean id="cat" class="com.pojo.cat"/>
    <bean id="dog" class="com.pojo.dog"/>


    <bean id="people" class="com.pojo.people"/>
</beans>

import com.pojo.people;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Mytest {
    @Test
    public void test01(){
        ApplicationContext Context = new ClassPathXmlApplicationContext("beans.xml");
        people people = Context.getBean("people", people.class);

        people.getCat().shout();
        people.getDog().shout();
    }
}

@Resource

@Resource
private cat cat;
@Resource
private dog dog;
private String name;

12.Spring注解开发

在spring4之后，要使用注解开发，必须保证aop的包导入了

1.bean

2.属性如何注入

@Component
public class User {
    @Value("gukeyang")
    public String name ;


    @Value("value-set")
    public void setName(String name) {
        this.name = name;
    }
}

3.衍生的注解

4.自动装配置

5.作用域

6.小结

<context:component-scan base-package="com.gukeyang.pojo"/>
<context:annotation-config/>

13.使用JavaConfig实现配置

实体类

@Component

public class User{

配置文件

测试类

14.代理模式

为什么要学习代理模式？因为这是SpringAop的底层

代理模式的分类：静态代理和动态代理

静态代理

动态代理

Proxy代理，InvocationHandler

动态代理的好处：

可以使真实角色的操作更加纯粹！不用去关注一些公共的业务。

公共也就交给代理角色，实现业务的分工！

公共业务发生扩展的时候，方便集中管理

一个动态代理类代理的是一个接口，一般就是对应的一类业务

一个动态代理类可以代理多个类，只要实现同一个接口即可

15.AOP的实现方式

使用Spring实现AOP

<dependencies>
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.9.4</version>
    </dependency>
</dependencies>

<!-- 方式一：使用原生Spring API接口-->
<!--配置aop：需要导入aop的约束-->
<aop:config>
    <!--切入点-->
    <aop:pointcut id="pointcut" expression="execution(* com.kuang.service.UserServiceImpl.*(..))"/>

    <!--执行环绕增加-->
    <aop:advisor advice-ref="log " pointcut-ref="pointcut"/>
    <aop:advisor advice-ref="afterLog" pointcut-ref="pointcut"/>
</aop:config>

public interface UserService {
    public void add();
    public void delete();
    public void update();
    public void select();

}

public class UserServiceImpl implements UserService{

    @Override
    public void add() {
        System.out.println("增加了一个用户");
    }

    @Override
    public void delete() {
        System.out.println("删除了一个用户");
    }

    @Override
    public void update() {
        System.out.println("修改了一个用户");
    }

    @Override
    public void select() {
        System.out.println("查询了一个用户");
    }
}

import org.springframework.aop.MethodBeforeAdvice;

import java.lang.reflect.Method;

public class log implements MethodBeforeAdvice {

    //method：要执行的目标对象的方法
    //args：参数
    //target：目标对象
    @Override
    public void before(Method method, Object[] args, Object target) throws Throwable {

        System.out.println(target.getClass().getName()+"的"+method.getName()+"被执行了" );
    }
}

package com.kuang.log;

import org.springframework.aop.AfterReturningAdvice;

import java.lang.reflect.Method;

public class AfterLog implements AfterReturningAdvice {

    //returnValue返回值
    @Override
    public void afterReturning(Object returnValue, Method method, Object[] args, Object target) throws Throwable {
        System.out.println("执行了"+method.getName()+"返回结果为："+returnValue);
    }
}

import com.kuang.service.UserService;
import com.kuang.service.UserServiceImpl;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        //动态代理是接口
        UserService UserService = (UserService) context.getBean("UserService");

        UserService.select();
    }
}

自定义来实现AOP（主要是切面定义）

package com.kuang.diy;

public class DiyPointCut {
    public void before(){
        System.out.println("=======方法执行前========" );
    }

    public void after(){
        System.out.println("=======方法执行后========" );
    }
}

<!--方式二：自定义类-->
<bean id="diy" class="com.kuang.diy.DiyPointCut"/>
<aop:config>
    <aop:aspect ref="diy">
        <aop:pointcut id="point" expression="execution(* com.kuang.service.UserServiceImpl.*(..))"/>
        <aop:before method="before" pointcut-ref="point"/>
        <aop:after method="after" pointcut-ref="point"/>
    </aop:aspect>
</aop:config>

import com.kuang.service.UserService;
import com.kuang.service.UserServiceImpl;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        //动态代理是接口
        UserService UserService = (UserService) context.getBean("UserService");

        UserService.select();
    }
}

使用注解实现AOP

16.整合Mybatis

步骤：

1.导入相关的jar包

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.20</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.0.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.4</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>
    </dependencies>

2.编写配置文件

3.测试

16.1整合mybatis方式一

什么是mybatis-spring

http://mybatis.org/spring/zh/sqlsession.html

SqlSessionTemplate

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd">



    <!--DataSource 使用spring的数据源替换mybatis的配置 c3p0 dbcp druid-->
    <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?useSSL=false&serverTimeznotallow=UTC"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </bean>
    <!--sqlSessionFactory-->

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--绑定配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>
    
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">

        <!--只能使用构造器注入，没有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>

    </bean>

    <bean id="userMapper" class="com.gu.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>


</beans>

package com.gu.mapper;

import com.gu.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;

import java.util.List;

public class UserMapperImpl implements UserMapper{

    private SqlSessionTemplate sqlSession;

    public void setSqlSession(SqlSessionTemplate sqlSession) {
        this.sqlSession = sqlSession;
    }

    @Override
    public List<User> selectUser() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.selectUser();
    }
}

import com.gu.mapper.UserMapper;
import com.gu.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;


public class MyTest {
    @Test
    public void test() throws IOException {
/*        String resources = "mybatis-config.xml";
        InputStream in = Resources.getResourceAsStream(resources);

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        SqlSession sqlSession = sqlSessionFactory.openSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.selectUser();
        for (User user : userList) {

            System.out.println(user);
            
        }*/
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-dao.xml");
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        for (User user : userMapper.selectUser()) {
            System.out.println(user);
            
        }
    }
}

16.2整合mybatis方式二

SqlSessionDaoSupport

<bean id="userMapper2" class="com.gu.mapper.UserMapperImpl2">
    <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>

package com.gu.mapper;

import com.gu.pojo.User;
import org.mybatis.spring.support.SqlSessionDaoSupport;

import java.util.List;

public class UserMapperImpl2 extends SqlSessionDaoSupport implements UserMapper {

    @Override
    public List<User> selectUser() {
        return getSqlSession().getMapper(UserMapper.class).selectUser();
    }
}

17.回顾mybatis

编写实体类

package com.gu.pojo;
import lombok.Data;
@Data
public class User {
    private int id;
    private String name;
    private String pwd;
}

编写核心配置文件

<?xml versinotallow="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <package name="com.gu.pojo"/>
    </typeAliases>
    
    <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?serverTimeznotallow=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper class="com.gu.mapper.UserMapper"/>
    </mappers>
    
</configuration>

<?xml versinotallow="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">
    <parent>
        <artifactId>spring-study</artifactId>
        <groupId>com.gukeyang</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>spring-04-mybatis</artifactId>

    <properties>
        <maven.compiler.source>10</maven.compiler.source>
        <maven.compiler.target>10</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.20</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.0.5.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.4</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.10</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

    <!-- 项目打包时会将java目录中的*.xml文件也进行打包 -->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

</project>

编写接口

package com.gu.mapper;

import com.gu.pojo.User;

import java.util.List;

public interface UserMapper {
    public List<User> selectUser();
}

编写mapper.xml

<?xml versinotallow="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.gu.mapper.UserMapper">
    <select id="selectUser" resultType="User">
        select * from mybatis.user;
    </select>

</mapper>

测试

import com.gu.mapper.UserMapper;
import com.gu.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;


public class MyTest {
    @Test
    public void test() throws IOException {
        String resources = "mybatis-config.xml";
        InputStream in = Resources.getResourceAsStream(resources);

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        SqlSession sqlSession = sqlSessionFactory.openSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.selectUser();
        for (User user : userList) {

            System.out.println(user);
            
        }
    }
}

18.声明式事务

回顾事务

要么都成功，要么都失败

事务在项目开发中，涉及到数据的一致性问题，不能马虎

确保完整性和一致性

事务的ACID原则：

原子性

一致性

隔离性多个业务可能同时操作同一个资源，防止数据损坏

持久性事务一旦提交，无论系统发生什么问题，结果都不会再被影响，被持久化的写到存储器中！

spring的事务管理

声明式 AOP

编程式需要在代码中进行事务的管理

<!--配置声明式事务-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource"/>
</bean>
<!--结合AOP实现事务的织入-->
<!--配置事务的类-->
<tx:advice id="txAdvice" transaction-manager="transactionManager" >
    <!--给哪些方法配置事务-->
    <!--配置事务传播特性：new  propagation-->
    <tx:attributes>
        <tx:method name="add " propagation="REQUIRED"/>
        <tx:method name="delete " propagation="REQUIRED"/>
        <tx:method name="update " propagation="REQUIRED"/>
        <tx:method name="query " read-only="true"/>
        <tx:method name="* " propagation="REQUIRED"/>
    </tx:attributes>
</tx:advice>

<!--配置事务切入-->
<aop:config>
    <aop:pointcut id="txPointCut" expression="execution(* com.gu.mapper.*.*(..))"/>
    <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
</aop:config>

标签：http,Spring,void,springframework,学习,org,import,public
From： https://blog.51cto.com/u_15971093/6064526