Spring 容器創建 依賴注入 web整合 註解使用

知道爲什麼這樣做 ，以及這樣做的好處

Spring 介紹

 Spring 容器就是用來創建bean對象的容器，對象從Spring容器中獲得， 有兩大特性 IOC AOP

1. Spring容器的創建

1.1.1 搭建開發環境jar包導入，添加約束

    <!-- jdk 1.8 -->

    <build>
        <plugins>
            <!-- maven的編譯插件，用於指定我們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>

    <!-- 依賴包||||||||||||||||||||||||||||| -->

    <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個包 |||||||||||||||||||||||||| -->
        <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>

約束添加 –

爲什麼這麼添加不知道？？ 約束的作用 意義是什麼？

<?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 創建容器 applicationContext.xml 容器

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

1.1.3 創建對象代碼

        //創建spring容器
        ApplicationContext applicationContext =new ClassPathXmlApplicationContext("beans.xml");
        //從容器中獲取對象
        Person bean = (Person) applicationContext.getBean("personid");

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

1.2.1 創建Spring對象的三種方式

第一種

第二種 靜態工廠獲取對象

第三種 實例工廠獲取對象

2. 依賴注入

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="劉廣睿"></property>
            <property name="sex" value="男"></property>
            <property name="hairColor" value="黑色"></property>
            <property name="age" value="27"></property>
     </bean>

2.2 構造方法 引用類型注入

 <bean id="superperson" class="com.ruirui.dao.SuperPerson">
            <property name="name" value="路費"></property>
            <property name="address" value="東海"></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>周杰倫</value>
                    <value>陳奕迅</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標籤 同c標籤使用

 <?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整個

3.1 添加兩個jar包

          <!-- spring 跟 web 整個 需要導入兩個依賴包  spring-web  servlet包 -->
        <dependency>

            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.2.4.RELEASE</version>

        </dependency>

        <!-- 導入servlet的包 -->
        <dependency>

                <groupId>javax.servlet</groupId>
                <artifactId>javax.servlet-api</artifactId>
                <version>3.1.0</version>
                <scope>provided</scope>

        </dependency>

3.2 配置監聽器

 <!-- web-spring  自帶的監聽器配置 -->
  <listener>
      <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener> 

  <context-param>
        <param-name>contextConfigLocation</param-name> 
          <!-- 這個有個路徑問題 等會部署的時候去tomcat看看 -->

        <param-value>classpath:spring_web_bean.xml</param-value>
  </context-param>

3.3 從request預中 獲取spring容器中所有數據

 * 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. 註解的使用

4.1 導入註解包

<!-- 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中需要添加約束，並且配置需要掃描的包，告訴spring容器開啓註解模式

    <!--剛纔這裏缺一個約束  -->
        http://www.springframework.org/schema/context



<context:annotation-config />

       <context:component-scan base-package="com.ruirui.dao"></context:component-scan> 

常用的註解

第一個註解：@component ：該類可以被註解創建實例
第二個註解：@Value     給基本數據類型賦值
第三個註解： @Autowired  用於注入對象屬性
@Resource  給引用數據類型定義ID
@Controller：用於web層
@Service ：用於業務邏輯層
@Reposiroty ：用於Dao層

@Autowired+@Qualifier  ===  @Resource

Spring配置文件

    <!-- 代表採用註解方式創建實例 -->
      <context:annotation-config />   
        <!-- 掃描這個包下面的所有註解 -->
       <context:component-scan base-package="com.ruirui.dao"></context:component-scan> 

註解的使用

Person類

@Component(value="person")    //person 代表的是對象的ID
public class Person {

    @Value(value="100")      //value 代表給成員變量賦值
    private Integer  age; 

    private String hairColor;

    private String sex ;   

    @Resource(name="superson")
    private  SuperPerson superPerson;   // Person內部的引用數據類型定義id superson

@Component(value="superson")
public class SuperPerson { 

    public  void fly() {

        System.out.println("會飛");
    }


}