【Spring】学习笔记003依赖注入

1.构造器注入

　　构造器方式注入在之前的学习笔记中已经记录：https://www.cnblogs.com/AirCL/p/14350568.html

2.Set方式注入

　　依赖注入：Set注入

　　　　依赖： bean对象的创建依赖于容器
　　　　注入：bean对象中的所有属性，由容器来注入

　　环境搭建：假设我们有实体类Address和Student如下：

public class Address implements Serializable {

    private String address;

    public String getAddress() {
        return address;
    }

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

public class Student implements Serializable {

    private String name;
    private Address address;
    private String[] books;
    private List<String> hobby;
    private Map<String,String> card;
    private Set<String> games;
    private String wife;
    private Properties info;

    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 String getWife() {
        return wife;
    }

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

    public Properties getInfo() {
        return info;
    }

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

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

　　下面看一下各种类型的Set注入

    <bean id="addressBean" class="com.aircl.domain.Address">
        <property name="address" value="This is my address!"></property>
    </bean>

    <bean id="studentBean" class="com.aircl.domain.Student">
        <!--第一种：普通值注入-->
        <property name="name" value="aircl"></property>
        <!--第二种：bean注入-->
        <property name="address" ref="addressBean"></property>
        <!--第三种：数组注入-->
        <property name="books">
            <array>
                <value>book1</value>
                <value>book2</value>
                <value>book3</value>
                <value>book4</value>
            </array>
        </property>
        <!--第四种：List注入-->
        <property name="hobby">
            <list>
                <value>hobby1</value>
                <value>hobby2</value>
                <value>hobby3</value>
                <value>hobby4</value>
            </list>
        </property>
        <!--第五种：Map注入-->
        <property name="card">
            <map>
                <entry key="idCard" value="123456"/>
                <entry key="studentCard" value="12138"/>
            </map>
        </property>
        <!--第六种：Set注入-->
        <property name="games">
            <set>
                <value>set1</value>
                <value>set2</value>
                <value>set3</value>
            </set>
        </property>
        <!--第七种：null注入-->
        <property name="wife">
            <null/>
        </property>
        <!--第八种：properties注入-->
        <property name="info">
            <props>
                <prop key="info1">This is info1</prop>
                <prop key="info2">This is info2</prop>
            </props>
        </property>
    </bean>

3.拓展方式注入

3.1 p命名空间注入

　　p命名空间使用存在前提，需要先把需要的内容导入如下，同时需要无参构造方法

<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        
　　　　https://www.springframework.org/schema/beans/spring-beans.xsd">
</beans>

　　然后进行使用

<!--p命名空间注入-->
<bean id="userBean" class="com.aircl.domain.User" p:name="aircl"></bean>

3.2 c命名空间注入

　　c命名空间使用同样需要把需要的东西导入，同时需要有参构造方法：

<?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">
</beans>

　　然后进行使用

<!--c命名空间注入-->
<bean id="userBean" class="com.aircl.domain.User" c:name="aircl"></bean>