优点：开源免费的框架（容器）。轻量级，非入侵式框架。控制反转（ioc），面向切面编程（aop）。支持事务处理，对框架整合的支持
控制反转IoC(Inversion of Control)，是一种设计思想，DI(依赖注入)是实现IoC的一种方法，
导包
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
创建beans.xml
创建接口以及实现类
创建服务层接口以及实现类
public class UserServiceImpl implements UserService {
private UserDao userDao;
?
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
?
@Override
public void getUser() {
userDao.getUser1();
}
}
在beans.xml中编写配置，注册成功类旁边会有小叶子??
<bean id="oracl" class="com.lt.pojo.oracl"/>
<bean id="sql" class="com.lt.pojo.sql"/>
<bean id="UserServiceImpl" class="com.lt.sevice.UserServiceImpl">
<property name="UserDao" ref="oracl"/>
</bean>
创建测试类测试
使用无参构造创建对象，默认。
有参创建对象三种方法
下标赋值
<bean id="user" class="com.lt.pojo.User">
<constructor-arg index="0" value=""/>
</bean>
类型赋值
<bean class="com.lt.pojo.User" id="user">
<constructor-arg type="java.lang.String" value=""/>
</bean>
参数名赋值
<bean class="com.lt.pojo.User" id="user">
<constructor-arg name="name" value=""/>
</bean>
构造器注入
通过set注入
依赖：bean创建的对象依赖于容器
注入：bean对象中的所有属性，由容器来注入
<?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:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/util https://www.springframework.org/schema/util/spring-util.xsd">
<bean class="com.lt.dao.Address" name="address"/>
<bean class="com.lt.dao.Student" name="student">
<property name="name" value="lllt"/>
<property name="address" ref="address"/>
<property name="book">
?
<array>
<value>1</value>
<value>2</value>
<value>3</value>
<value>4</value>
</array>
</property>
<property name="hobbies">
<list>
<value>11</value>
<value>22</value>
<value>33</value>
<value>44</value>
</list>
</property>
<property name="card">
<map>
<entry key="1" value="1"/>
</map>
</property>
<property name="games">
<set>
<value>4</value>
<value>5</value>
<value>6</value>
<value>7</value>
</set>
</property>
<property name="wife" >
<null/>
</property>
<property name="info">
<props>
<prop key="1">4</prop>
<prop key="2">3</prop>
<prop key="3">2</prop>
<prop key="4">1</prop>
</props>
</property>
</bean>
</beans>
拓展方式注入
p命名空间 set注入属性 xmlns:p="http://www.springframework.org/schema/p"
c命名空间 构造器 mlns:c="http://www.springframework.org/schema/c"
byname
<bean class="com.lt.dao.Student" name="student" autowire="byName"/> id唯一
bytype
<bean class="com.lt.dao.Student" name="student" autowire="byType"/> //保证全局class唯一
要使用需配置
会在容器上下文寻找和自己对象set后面的值对应的bean id
如：set Dog dog（）{} 则引入狗的id必须为dog而不能是其他
会在容器上下文寻找和自己对象属性类型相同的bean
如，set Dog dog（）{} 有Dog这个类就行 id可以不对应
作用在被引用对象的私有方法上，xml只需要引入类即可。如
@Autowired
private Dog dog;
@Autowired
private Cat cat;
<bean class="com.lt.pojo.Cat" id="cat123"/>
<bean class="com.lt.pojo.Dog" id="dog"/>
<bean class="com.lt.pojo.People" id="people" >
拓展
@Autowired(required = false)
//如果显示定义是false 表明该类属性可以为空
如果自动装配环境比较复杂，无法通过一个@Autowired去实现，我们可以使用@Qualifier（value=“xxx”）去配置使用，指定唯一对象注入
最高级，会先通过byName去查找，再通过byType查找，后边可以跟name= 去查找具体的
相当于注册，如
<bean class="com.lt.pojo.People" id="people" >
必须配合使用
<context:component-scan base-package="com.lt"/>
衍生注解：
dao：@Repository
service：@Service
controller @Controller
可以在属性字段赋值
@Component
@Data
public class User {
@Value("lt")
private String name;
}
?
?
?
@Configuration
public class UserConf {
@Bean
public User getUser(){
return new User();
}
}
?
?
public static void main(String[] args) {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(UserConf.class);
User getUser = context.getBean("getUser", User.class);
System.out.println(getUser.getName());
}
方式一：使用spring的api接口
public class AfterLog implements AfterReturningAdvice {
public void afterReturning(Object o, Method method, Object[] objects, Object o1) throws Throwable {
System.out.println(o1.getClass().getName()+" "+method.getName());
}
}
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---
public class Log implements MethodBeforeAdvice {
public void before(Method method, Object[] objects, Object o) throws Throwable {
System.out.println(o.getClass().getName()+" "+method.getName());
}
}
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---
<bean class="com.lt.mapper.UserServiceImpl" name="userService"/>
<bean class="com.lt.log.AfterLog" name="afterLog"/>
<bean class="com.lt.log.Log" name="log"/>
<aop:config>
<aop:pointcut id="pointcut" expression="execution(* com.lt.mapper.UserServiceImpl.*(..))"/>
<aop:advisor advice-ref="log" pointcut-ref="pointcut"/>
<aop:advisor advice-ref="afterLog" pointcut-ref="pointcut"/>
</aop:config>
方式二：自定义来实现aop
public class Diy {
public void befor(){
System.out.println("-------------------------------------------");
} public void after(){
System.out.println("-------------------------------------------");
}
}
--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---
<bean class="com.lt.mapper.UserServiceImpl" name="userService"/>
<bean class="com.lt.Diy.Diy" name="diy"/>
<aop:config>
<aop:aspect ref="diy">
<aop:pointcut id="point" expression="execution(* com.lt.mapper.UserServiceImpl.*(..))"/>
<aop:before method="befor" pointcut-ref="point"/>
<aop:after method="after" pointcut-ref="point"/>
</aop:aspect>
</aop:config>
方式三：使用注解来实现
@Aspect
public class Diy {
@Before("execution(* com.lt.mapper.UserServiceImpl.*(..))")
public void befor(){
System.out.println("-------------------------------------------");
}
@After("execution(* com.lt.mapper.UserServiceImpl.*(..))")
public void after(){
System.out.println("-------------------------------------------");
}
}
?
?
<bean class="com.lt.Diy.Diy" name="diy"/>
<aop:aspectj-autoproxy/> //不要忘记开自动
<!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.9.5</version>
</dependency>
?
原文：https://www.cnblogs.com/ltdh/p/12530359.html