Spring-DI

三、Spring-DI

3、DI（依赖注入 Dependence Injection）：

3.1 set注入（使用set方法注入属性）

​ 前提：类的属性实现set方法：

public class TestDI {
    private String name;
    private TestBean testBean;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public TestBean getTestBean() {
        return testBean;
    }

    public void setTestBean(TestBean testBean) {
        this.testBean = testBean;
    }
}

public class TestBean {

    public void test(){
        System.out.println("testBean");
    }
}

​ spring.xml配置,基本数据类型以及它的包装类和String类型都可以通过value进行注入，其他引用类型的数据通过ref引用其他bean对象注入到属性中,注意属性名要和property中的name对应：

<bean id="testDI" class="com.xxx.TestDI">
	<property name="name" value="I'm Test"/>
	<property name="testBean" ref="testBean"/>
</bean>
<bean id="testBean" class="com.xxx.TestBean"/>

​ 测试

public class App {
    public static void main( String[] args ){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        TestDI testDI = applicationContext.getBean(TestDI.class);
        testDI.getTestBean().test();
    }
}

​ 结果：

3.2 构造注入（使用带参构造方法注入属性）

​ 前提：要有带参构造方法

public class TestConstructor {
    private String name;
    private String pwd;
    public TestBean testBean;

    public TestConstructor(String name, String pwd, TestBean testBean) {
        this.name = name;
        this.pwd = pwd;
        this.testBean = testBean;
    }
}

public class TestBean {

    public void test(){
        System.out.println("testBean");
    }
}

​ spring.xml:

​ 构造注入有三种指定方式:

​ 1、index 通过索引注入按照带参构造器中的顺序(String name （index=0) , String pwd, TestBean testBean)

​ 2、type通过类型注入也是按照构造器中的顺序注入

​ 3、name通过构造器中的参数名注入（要保持一致）

<bean id="testConstructor" class="com.xxx.TestConstructor">
    <constructor-arg index="1" value="hhhhh"/>
    <constructor-arg type="java.lang.String" value="111"/>
    <constructor-arg name="testBean" ref="testBean"/>
</bean>

<bean id="testBean" class="com.xxx.TestBean"/>

​ 测试：

public class App {
    public static void main( String[] args ){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        TestConstructor testConstructor = applicationContext.getBean(TestConstructor.class);
        System.out.println(testConstructor.name);
        System.out.println(testConstructor.pwd);
        testConstructor.testBean.test();
    }
}

​ 结果：

3.3其他类型属性的注入

3.3.1 Array数组注入

public class TestArray {
    private Integer ids[];

    public void setIds(Integer[] ids) {
        this.ids = ids;
    }
    
    public Integer[] getIds() {
        return ids;
    }
    
    @Override
    public String toString() {
        return "TestArray{" +
                "ids=" + Arrays.toString(ids) +
                '}';
    }
}

spring.xml

    <bean id="testArray" class="com.xxx.TestArray">
        <property name="ids">
            <array>
                <value>1</value>
                <value>2</value>
                <value>3</value>
            </array>
        </property>
    </bean>

测试：

public class App {
    public static void main( String[] args ){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        TestArray testArray = applicationContext.getBean(TestArray.class);
        for(Integer id : testArray.getIds()){
            System.out.println(id);
        }
    }
}

结果：

3.3.2 List集合注入

public class TestList {
    private List<String> stringList;

    public List<String> getStringList() {
        return stringList;
    }

    public void setStringList(List<String> stringList) {
        this.stringList = stringList;
    }

    @Override
    public String toString() {
        return "TestList{" +
                "stringList=" + stringList +
                '}';
    }
}

​ spring.xml

    <bean id="testList" class="com.xxx.TestList">
        <property name="stringList">
            <list>
                <value>哈哈哈</value>
                <value>？？？</value>
                <value>哈哈哈</value>
            </list>
        </property>
    </bean>

​ 测试：

public class App {
    public static void main( String[] args ){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        TestList testList = applicationContext.getBean(TestList.class);
        System.out.println(testList);
    }
}

​ 结果：

3.3.3 Set集合注入：

public class TestSet {
    private Set<String> set;

    public Set<String> getSet() {
        return set;
    }

    public void setSet(Set<String> set) {
        this.set = set;
    }

    @Override
    public String toString() {
        return "TestSet{" +
                "set=" + set +
                '}';
    }
}

​ spring.xml

    <bean id="testSet" class="com.xxx.TestSet">
        <property name="set">
            <set>
                <value>哈哈哈</value>
                <value>？？？</value>
                <value>哈哈哈</value>
            </set>
        </property>
    </bean>

​ 测试：

public class App {
    public static void main( String[] args ){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        TestSet testSet = applicationContext.getBean(TestSet.class);
        System.out.println(testSet);
    }
}

​ 结果：

3.3.4 Map注入

public class TestMap {
    private Map<String, Object> map;

    @Override
    public String toString() {
        return "TestMap{" +
                "map=" + map +
                '}';
    }

    public Map<String, Object> getMap() {
        return map;
    }

    public void setMap(Map<String, Object> map) {
        this.map = map;
    }
}

​ spring.xml

    <bean id="testMap" class="com.xxx.TestMap">
        <property name="map">
            <map>
                <entry>
                    <key><value>哈哈哈</value></key>
                    <value>？？？</value>
                </entry>
                <entry>
                    <key><value>testBean</value></key>
                    <ref bean="testBean"></ref>
                </entry>
            </map>
        </property>
    </bean>
    <bean id="testBean" class="com.mage.test.TestBean"/>

​ 测试：

public class App {
    public static void main( String[] args ){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        TestMap testMap = applicationContext.getBean(TestMap.class);
        TestBean teseBean = (TestBean)testMap.getMap().get("testBean");
        System.out.println(testMap.getMap().get("哈哈哈"));
        teseBean.test();
    }
}

​ 结果：

3.3.5 Properties注入

public class TestProperties {
    private Properties properties;

    @Override
    public String toString() {
        return "TestProperties{" +
                "properties=" + properties +
                '}';
    }

    public Properties getProperties() {
        return properties;
    }

    public void setProperties(Properties properties) {
        this.properties = properties;
    }
}

​ spring.xml

    <bean id="testProperties" class="com.mage.test.TestProperties">
        <property name="properties">
            <props>
                <prop key="哈哈哈">？？？</prop>
                <prop key="？？？">哈哈哈</prop>
            </props>
        </property>
    </bean>

​ 测试：

public class App {
    public static void main( String[] args ){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        TestProperties testProperties = applicationContext.getBean(TestProperties.class);
        System.out.println(testProperties);
    }
}

​ 结果：