学习 Spring (六) 自动装配

Spring入门篇 学习笔记

  1. No: (默认)不做任何操作
  2. byName: 根据属性名自动装配。此选项将检查容器并根据名字查找与属性完全一致的 bean,并将其与属性自动装配
  3. byType: 如果容器中存在一个与指定属性类型相同的 bean,那么将与该属性自动装配;如果存在多个该类型的 bean,那么抛出异常,并指出不能使用 byType 方式进行自动装配;如果没有找到相匹配的 bean,则什么事都不发生
  4. constructor: 与 byType 方式类似,不同之处在于它应用于构造器参数。如果容器中没有找到与构造器参数类型一致的 bean 则抛出异常

准备工作,添加 AutoWiringDAO:

public class AutoWiringDAO {

	public void say(String word) {
System.out.println("AutoWiringDAO : " + word);
} }

byName

添加 AutoWiringServiceByName:

public class AutoWiringServiceByName {

	private AutoWiringDAO autoWiringDAO;

	public void setAutoWiringDAO(AutoWiringDAO autoWiringDAO) {
this.autoWiringDAO = autoWiringDAO;
} public void say(String word) {
this.autoWiringDAO.say(word);
} }

添加配置文件 spring-autowiring-byname.xml:

<?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"
default-autowire="byName"> <bean id="autoWiringService" class="com.karonda.autowiring.AutoWiringServiceByName" ></bean> <bean id="autoWiringDAO" class="com.karonda.autowiring.AutoWiringDAO" ></bean> </beans>

添加测试类:

@RunWith(BlockJUnit4ClassRunner.class)
public class TestAutoWiringByName extends UnitTestBase { public TestAutoWiringByName() {
super("classpath:spring-autowiring-byname.xml");
} @Test
public void testSay() {
AutoWiringServiceByName service = super.getBean("autoWiringService");
service.say(" this is a test");
} }

byType

添加 AutoWiringServiceByType:

public class AutoWiringServiceByType {

	private AutoWiringDAO autoWiringDAO;

	public void setAutoWiringDAO(AutoWiringDAO autoWiringDAO) {
this.autoWiringDAO = autoWiringDAO;
} public void say(String word) {
this.autoWiringDAO.say(word);
} }

添加配置文件 spring-autowiring-bytype.xml:

<?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"
default-autowire="byType"> <bean id="autoWiringService" class="com.karonda.autowiring.AutoWiringServiceByType" ></bean> <bean class="com.karonda.autowiring.AutoWiringDAO" ></bean> </beans>

添加测试类:

@RunWith(BlockJUnit4ClassRunner.class)
public class TestAutoWiringByType extends UnitTestBase { public TestAutoWiringByType() {
super("classpath:spring-autowiring-bytype.xml");
} @Test
public void testSay() {
AutoWiringServiceByType service = super.getBean("autoWiringService");
service.say(" this is a test");
} }

constructor

添加 AutoWiringServiceConstructor

public class AutoWiringServiceConstructor {

	private AutoWiringDAO autoWiringDAO;

	public AutoWiringServiceConstructor(AutoWiringDAO autoWiringDAO){
this.autoWiringDAO = autoWiringDAO;
}
public void say(String word) {
this.autoWiringDAO.say(word);
} }

添加配置文件 spring-autowiring-constructor.xml:

<?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"
default-autowire="constructor"> <bean id="autoWiringService" class="com.karonda.autowiring.AutoWiringServiceConstructor" ></bean> <bean class="com.karonda.autowiring.AutoWiringDAO" ></bean> </beans>

添加测试类:

@RunWith(BlockJUnit4ClassRunner.class)
public class TestAutoWiringConstructor extends UnitTestBase { public TestAutoWiringConstructor() {
super("classpath:spring-autowiring-constructor.xml");
} @Test
public void testSay() {
AutoWiringServiceConstructor service = super.getBean("autoWiringService");
service.say(" this is a test");
} }

源码:learning-spring

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