Spring 容器创建 依赖注入 web整合 注解使用

知道为什么这样做 ，以及这样做的好处

Spring 介绍

 Spring 容器就是用来创建bean对象的容器，对象从Spring容器中获得， 有两大特性 IOC AOP

1. Spring容器的创建

1.1.1 搭建开发环境jar包导入，添加约束

    <!-- jdk 1.8 -->    <build>        <plugins>            <!-- maven的编译插件，用于指定我们jdk的版本 -->            <plugin>                <groupId>org.apache.maven.plugins</groupId>                <artifactId>maven-compiler-plugin</artifactId>                <configuration>                    <source>1.8</source>                    <target>1.8</target>                    <encoding>UTF-8</encoding>                </configuration>            </plugin>        </plugins>    </build>    <!-- 依赖包||||||||||||||||||||||||||||| -->    <dependencies>        <!-- log包 4 -->        <dependency>            <groupId>org.bgee.log4jdbc-log4j2</groupId>            <artifactId>log4jdbc-log4j2-jdbc4.1</artifactId>            <version>1.16</version>        </dependency>        <dependency>            <groupId>org.slf4j</groupId>            <artifactId>slf4j-api</artifactId>            <version>1.7.13</version>        </dependency>        <dependency>            <groupId>org.slf4j</groupId>            <artifactId>slf4j-log4j12</artifactId>            <version>1.7.5</version>        </dependency>        <!-- https://mvnrepository.com/artifact/log4j/log4j -->        <dependency>            <groupId>log4j</groupId>            <artifactId>log4j</artifactId>            <version>1.2.16</version>        </dependency>        <!-- spring 4个包 |||||||||||||||||||||||||| -->        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-context</artifactId>            <version>4.2.4.RELEASE</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-core</artifactId>            <version>4.2.4.RELEASE</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-beans</artifactId>            <version>4.2.4.RELEASE</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-expression</artifactId>            <version>4.2.4.RELEASE</version>        </dependency>

约束添加 –

为什么这么添加不知道？？ 约束的作用 意义是什么？

<?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">

1.1.2 创建容器 applicationContext.xml 容器

 <bean id="personid" class="com.ruirui.dao.Person"> </bean>

1.1.3 创建对象代码

        //创建spring容器        ApplicationContext applicationContext =new ClassPathXmlApplicationContext("beans.xml");        //从容器中获取对象        Person bean = (Person) applicationContext.getBean("personid");        System.out.println(bean.toString());

1.2.1 创建Spring对象的三种方式

第一种

第二种 静态工厂获取对象

第三种 实例工厂获取对象

2. 依赖注入

2.1 get set方法注入

<bean id="personid" class="com.ruirui.dao.Person"  init-method="init" destroy-method="destory">             <property name="name" value="刘广睿"></property>            <property name="sex" value="男"></property>            <property name="hairColor" value="黑色"></property>            <property name="age" value="27"></property>     </bean>

2.2 构造方法 引用类型注入

 <bean id="superperson" class="com.ruirui.dao.SuperPerson">            <property name="name" value="路费"></property>            <property name="address" value="东海"></property>    </bean>    <bean id="personid_two" class="com.ruirui.dao.Person" >        <constructor-arg name="superPerson" ref="superperson"></constructor-arg>        <constructor-arg name="name" value="冬雪"></constructor-arg>    </bean>

2.3 set list map properies 注入

     <property name="list" >                    <list>                        <value>1</value>                        <value>2</value>                        <value>"你好北京"</value>                     </list>            </property>             <property name="set">                <set>                    <value>周杰伦</value>                    <value>陈奕迅</value>                </set>            </property>             <property name="map">                <map>                    <entry key="tom" value="tom"></entry>                    <entry key="mary" value="mary"></entry>                    <entry key="rose" value="mary"></entry>                </map>            </property>              <property name="properties">                <props>                    <prop key="1">1</prop>                    <prop key="2">1</prop>                    <prop key="3">1</prop>                </props>            </property>

2.4 p标签 同c标签使用

 <?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: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="person_p" class="com.ruirui.dao.Person" p:name="索隆" p:age="29"></bean>     <bean id ="superPersonID"  class="com.ruirui.dao.SuperPerson" ></bean>    <bean id="person_p_P" class="com.ruirui.dao.Person" c:name="索隆" c:superPerson="#{superPersonID}"></bean>

3. Web整个

3.1 添加两个jar包

          <!-- spring 跟 web 整个 需要导入两个依赖包  spring-web  servlet包 -->        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-web</artifactId>            <version>4.2.4.RELEASE</version>        </dependency>        <!-- 导入servlet的包 -->        <dependency>                <groupId>javax.servlet</groupId>                <artifactId>javax.servlet-api</artifactId>                <version>3.1.0</version>                <scope>provided</scope>        </dependency>

3.2 配置监听器

 <!-- web-spring  自带的监听器配置 -->  <listener>      <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>  </listener>   <context-param>        <param-name>contextConfigLocation</param-name>           <!-- 这个有个路径问题 等会部署的时候去tomcat看看 -->        <param-value>classpath:spring_web_bean.xml</param-value>  </context-param>

3.3 从request预中 获取spring容器中所有数据

 * Servlet implementation class MyServlet */public class MyServlet extends HttpServlet {    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // TODO Auto-generated method stub        response.getWriter().append("Served at: ").append(request.getContextPath());         WebApplicationContext attribute = (WebApplicationContext) request.getServletContext().getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);        SuperPerson bean = (SuperPerson) attribute.getBean("person_p");        System.out.println(bean.toString());    }

4. 注解的使用

4.1 导入注解包

<!-- https://mvnrepository.com/artifact/org.springframework/spring-aop --><dependency>    <groupId>org.springframework</groupId>    <artifactId>spring-aop</artifactId>    <version>4.2.4.RELEASE</version></dependency>

在bean.xml中需要添加约束，并且配置需要扫描的包，告诉spring容器开启注解模式

    <!--刚才这里缺一个约束  -->        http://www.springframework.org/schema/context<context:annotation-config />       <context:component-scan base-package="com.ruirui.dao"></context:component-scan> 

常用的注解

第一个注解：@component ：该类可以被注解创建实例第二个注解：@Value     给基本数据类型赋值第三个注解： @Autowired  用于注入对象属性@Resource  给引用数据类型定义ID@Controller：用于web层@Service ：用于业务逻辑层@Reposiroty ：用于Dao层@Autowired+@Qualifier  ===  @Resource

Spring配置文件

    <!-- 代表采用注解方式创建实例 -->      <context:annotation-config />           <!-- 扫描这个包下面的所有注解 -->       <context:component-scan base-package="com.ruirui.dao"></context:component-scan> 

注解的使用

Person类

@Component(value="person")    //person 代表的是对象的IDpublic class Person {    @Value(value="100")      //value 代表给成员变量赋值    private Integer  age;     private String hairColor;    private String sex ;       @Resource(name="superson")    private  SuperPerson superPerson;   // Person内部的引用数据类型定义id superson

@Component(value="superson")public class SuperPerson {     public  void fly() {        System.out.println("会飞");    }}