Spring IOC 3

最新推荐文章于 2025-12-18 13:32:52 发布

翻译最新推荐文章于 2025-12-18 13:32:52 发布 · 120 阅读

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<beans ...>
    <bean id="renderer"
        class="com.apress.prospring5.ch2.decoupled.StandardOutMessageRenderer">
        <property name="messageProvider" ref="provider"/>
    </bean>
    <bean id="provider"
        class="com.apress.prospring5.ch2.decoupled.HelloWorldMessageProvider"/>
</beans>

<?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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="renderer"
        class="com.apress.prospring5.ch2.decoupled.StandardOutMessageRenderer"
        p:messageProvider-ref="provider"/>
    <bean id="provider"
        class="com.apress.prospring5.ch2.decoupled.HelloWorldMessageProvider"/>
</beans>

两种Bean注入方式

import org.springframework.beans.factory.annotation.Autowired;
@Service("renderer")
public class StandardOutMessageRenderer implements MessageRenderer {
...
    @Override
    @Autowired
    public void setMessageProvider(MessageProvider provider) {
        this.messageProvider = provider;
    }
}

通过注解Setter注入

import com.apress.prospring5.ch2.decoupled.MessageProvider;
public class ConfigurableMessageProvider
    implements MessageProvider {
        private String message;
        public ConfigurableMessageProvider(String message) {
            this.message = message;
        }
        @Override
        public String getMessage() {
            return message;
        }
}

<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">
    <bean id="messageProvider"
        class="com.apress.prospring5.ch3.xml.ConfigurableMessageProvider">
        <constructor-arg value="I hope that someone gets my message in a bottle"/>
    </bean>
</beans>

构造器注入

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    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="provider"
        class="com.apress.prospring5.ch3.xml.ConfigurableMessageProvider"
        c:message="I hope that someone gets my message in a bottle"/>
</beans>

另一种配置方式

import com.apress.prospring5.ch2.decoupled.MessageProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("provider")
public class ConfigurableMessageProvider implements MessageProvider {
        private String message;
        @Autowired
        public ConfigurableMessageProvider(
        (@Value("Configurable message") String message) {
                this.message = message;
        }
        @Override
        public String getMessage() {
                return this.message;
        }
}

<beans ...>
    <context:component-scan
          base-package="com.apress.prospring5.ch3.annotated"/>
    <bean id="message" class="java.lang.String"
          c:_0="I hope that someone gets my message in a bottle"/>
</beans>

构造器配置字符串

import com.apress.prospring5.ch2.decoupled.MessageProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("provider")
public class ConfigurableMessageProvider implements MessageProvider {
        private String message;
        @Autowired
        public ConfigurableMessageProvider(String message) {
                this.message = message;
        }
        @Override
        public String getMessage() {
                return this.message;
        }
}

使用Autowire

import com.apress.prospring5.ch2.decoupled.MessageProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("provider")
public class ConfigurableMessageProvider implements MessageProvider {
        private String message;
        @Autowired
        public ConfigurableMessageProvider(
        (@Value("Configurable message") String message) {
                this.message = message;
        }
        @Override
        public String getMessage() {
                return this.message;
        }
}

<beans ...>
    <context:component-scan
          base-package="com.apress.prospring5.ch3.annotated"/>
    <bean id="message" class="java.lang.String"
          c:_0="I hope that someone gets my message in a bottle"/>
</beans>

import com.apress.prospring5.ch2.decoupled.MessageProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("provider")
public class ConfigurableMessageProvider implements MessageProvider {
        private String message;
        @Autowired
        public ConfigurableMessageProvider(String message) {
                this.message = message;
        }
        @Override
        public String getMessage() {
                return this.message;
        }
}

构造器注入

import org.springframework.context.support.GenericXmlApplicationContext;
public class ConstructorConfusion {
    private String someValue;
    public ConstructorConfusion(String someValue) {
        System.out.println("ConstructorConfusion(String) called");
        this.someValue = someValue;
    }
    public ConstructorConfusion(int someValue) {
        System.out.println("ConstructorConfusion(int) called");
        this.someValue = "Number: " + Integer.toString(someValue);
    }
    public String toString() {
        return someValue;
    }
        public static void main(String... args) {
          GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();
          ctx.load("classpath:spring/app-context-xml.xml");
          ctx.refresh();
          ConstructorConfusion cc = (ConstructorConfusion)
                 ctx.getBean("constructorConfusion");
          System.out.println(cc);
          ctx.close
    }
}

<beans ...>
    <bean id="provider"
        class="com.apress.prospring5.ch3.xml.ConfigurableMessageProvider"
        c:message="I hope that someone gets my message in a bottle"/>
    <bean id="constructorConfusion"
        class="com.apress.prospring5.ch3.xml.ConstructorConfusion">
        <constructor-arg>
            <value>90</value>
        </constructor-arg>
    </bean>
</beans>

参数默认为字符串类型，也可以指定

@Service("constructorConfusion")
public class ConstructorConfusion {
        private String someValue;
        public ConstructorConfusion(String someValue) {
                System.out.println("ConstructorConfusion(String) called");
                this.someValue = someValue;
        }
        @Autowired
        public ConstructorConfusion(@Value("90") int someValue) {
                System.out.println("ConstructorConfusion(int) called");
                this.someValue = "Number: " + Integer.toString(someValue);
        }
        public String toString() {
                return someValue;
        }
        public static void main(String... args) {
                GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();
                ctx.load("classpath:spring/app-context-annotation.xml");
                ctx.refresh();
                ConstructorConfusion cc = (ConstructorConfusion)
                     ctx.getBean("constructorConfusion");
                System.out.println(cc);
                ctx.close();
        }
}

autowired是告诉Spring，构造对象时，用这个构造器。

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("singer")
public class Singer {
        @Autowired
        private Inspiration inspirationBean;
        public void sing() {
                System.out.println("... " + inspirationBean.getLyric());
        }
}

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component
public class Inspiration {
        private String lyric =
            "I can keep the door cracked open, to let light through";
        public Inspiration(
            @Value("For all my running, I can understand") String lyric) {
            this.lyric = lyric;
        }
        public String getLyric() {
            return lyric;
        }
        public void setLyric(String lyric) {
            this.lyric = lyric;
        }
}

字段注入