Spring-Ioc的入门应用

Ioc的入门应用

1.导包

2.创建spring容器

Springioc默认的是单例模式  

<?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-2.0.xsd">

<!--scope="singleton"单例

    prototype  多例-->

    <bean name="person" class="com.ujiuye.bean.PersonBean">

        <property name="pid" value="10"/>

        <property name="pname" value="张三"/>

        <property name="address" value="北京"/>

<!-- ref  引用其他对象-->

        <property name="card" ref="cardbean"/>

    </bean>

 

    <bean name="cardbean" class="com.ujiuye.bean.CardBean">

        <property name="cid" value="10"/>

        <property name="cnum" value="110"/>

    </bean>

</beans>

3.测试类

@Test

public void test1(){

//1.获取spring容器

        ApplicationContext app=new ClassPathXmlApplicationContext("bean.xml");

    //2.获取实例

        PersonBean p= (PersonBean) app.getBean("person");

        PersonBean p2= (PersonBean) app.getBean("person");

        System.out.println(p);

        System.out.println(p==p2);

    }

 

Name 和id区别：

Name后面可以跟多个名称   id只能有一个

name="person,p2,p3"

 

使用构造方法注入

<!--使用有参的构造方法di-->

    <bean name="p4" class="com.ujiuye.bean.PersonBean">

        <constructor-arg index="0" value="10"/>

        <constructor-arg index="1" value="李四"/>

        <constructor-arg index="2" value="上海"/>

    </bean>

set注入不同的类型

实体类

public class PersonBean {

    private int pid;

    private String pname;

    private String address;

    private CardBean card;

    private List<String> ls;

    private List<CardBean> cs;

    private Map map;

    private Properties properties;

<bean name="person,p2,p3" class="com.ujiuye.bean.PersonBean" scope="singleton">

        <property name="pid" value="10"/>

        <property name="pname" value="张三"/>

        <property name="address" value="北京"/>

       <!-- ref  引用其他对象-->

        <property name="card" ref="cardbean"/>

        <property name="ls">

            <list>

                <value>java</value>

                <value>python</value>

                <value>c++</value>

            </list>

        </property>

        <property name="cs">

            <list>

                <ref bean="cardbean"></ref>

                <ref bean="cardbean2"></ref>

            </list>

        </property>

        <property name="map">

            <map>

                <entry>

                    <key>

                        <value>name</value>

                    </key>

                    <value>admin</value>

                </entry>

                <entry>

                    <key>

                        <value>age</value>

                    </key>

                    <value>18</value>

                </entry>

            </map>

        </property>

        <property name="properties">

            <props>

                <prop key="username">root</prop>

                <prop key="password">123456</prop>

            </props>

        </property>

</bean>

 <bean name="cardbean" class="com.ujiuye.bean.CardBean">

        <property name="cid" value="10"/>

        <property name="cnum" value="110"/>

    </bean>

    <bean name="cardbean2" class="com.ujiuye.bean.CardBean">

        <property name="cid" value="10"/>

        <property name="cnum" value="110"/>

    </bean>

 

Ioc对于多态的支持

1.创建dao接口   service  中使用dao

2.ServiceImpl

public class CardServiceImpl  implements CardService {

    private  CardDao dao;

 

    public CardDao getDao() {

        return dao;

    }

 

    public void setDao(CardDao dao) {

        this.dao = dao;

    }

 3.容器

<bean name="cardService" class="com.ujiuye.service.CardServiceImpl">
    <property name="dao" ref="cardDao2"/>
</bean>
<bean name="cardDao1" class="com.ujiuye.dao.CardDaoImpl1"/>
<bean name="cardDao2" class="com.ujiuye.dao.CardDaoImpl2"/>

 

Dao

连接数据库进行增删改查的  sql

接口   实现类放sql

Mybatis  帮你写好了实现类   

Service  业务层   可能很复杂，有可能要涉及到多张表的操作，直接到dao里面增删改查的方法即可