Spring IOC 4

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.support.GenericXmlApplicationContext;
import org.springframework.stereotype.Service;
@Service("injectSimple")
public class InjectSimple {
        @Value("John Mayer")
        private String name;
        @Value("39")
        private int age;
        @Value("1.92")
        private float height;
        @Value("false")
        private boolean programmer;
        @Value("1241401112")
        private Long ageInSeconds;
        public static void main(String... args) {
                GenericXmlApplicationContext ctx =
                    new GenericXmlApplicationContext();
                ctx.load("classpath:spring/app-context-annotation.xml");
                ctx.refresh();
                InjectSimple simple = (InjectSimple) ctx.getBean("injectSimple");
                System.out.println(simple);
                ctx.close();
        }
        public String toString() {
                return "Name: " + name + "\n"
                                + "Age: " + age + "\n"
                                + "Age in Seconds: " + ageInSeconds + "\n"
                                + "Height: " + height + "\n"
                                + "Is Programmer?: " + programmer;
        }
}

配置参数

import org.springframework.stereotype.Component;
@Component("injectSimpleConfig")
public class InjectSimpleConfig {
        private String name = "John Mayer";
        private int age = 39;
        private float height = 1.92f;
        private boolean programmer = false;
        private Long ageInSeconds = 1_241_401_112L;
        public String getName() {
                return name;
        }
        public int getAge() {
                return age;
        }
        public float getHeight() {
                return height;
        }
        public boolean isProgrammer() {
                return programmer;
        }
        public Long getAgeInSeconds() {
                return ageInSeconds;
        }
}

<bean id="injectSimpleConfig"
        class="com.apress.prospring5.ch3.xml.InjectSimpleConfig"/>
    <bean id="injectSimpleSpel"
        class="com.apress.prospring5.ch3.xml.InjectSimpleSpel"
        p:name="#{injectSimpleConfig.name}"
        p:age="#{injectSimpleConfig.age + 1}"
        p:height="#{injectSimpleConfig.height}"
        p:programmer="#{injectSimpleConfig.programmer}"
        p:ageInSeconds="#{injectSimpleConfig.ageInSeconds}"/>

使用SPEL

import org.springframework.context.support.GenericXmlApplicationContext;
public class HierarchicalAppContextUsage {
    public static void main(String... args) {
        GenericXmlApplicationContext parent = new GenericXmlApplicationContext();
        parent.load("classpath:spring/parent-context.xml");
        parent.refresh();
        GenericXmlApplicationContext child = new GenericXmlApplicationContext();
        child.load("classpath:spring/child-context.xml");
        child.setParent(parent);
        child.refresh();
        Song song1 = (Song) child.getBean("song1");
        Song song2 = (Song) child.getBean("song2");
        Song song3 = (Song) child.getBean("song3");
        System.out.println("from parent ctx: " + song1.getTitle());
        System.out.println("from child ctx: " + song2.getTitle());
        System.out.println("from parent ctx: " + song3.getTitle());
        child.close();
        parent.close();
    }
}

子和父的上下文

<?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:context="http://www.springframework.org/schema/context"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans.xsd
          http://www.springframework.org/schema/context
          http://www.springframework.org/schema/context/spring-context.xsd
          http://www.springframework.org/schema/util
          http://www.springframework.org/schema/util/spring-util.xsd">
    <context:component-scan
          base-package="com.apress.prospring5.ch3.annotated"/>
    <util:map id="map" map-class="java.util.HashMap">
          <entry key="someValue" value="It's a Friday, we finally made it"/>
          <entry key="someBean" value-ref="lyricHolder"/>
    </util:map>
    <util:properties id="props">
        <prop key="firstName">John</prop>
        <prop key="secondName">Mayer</prop>
    </util:properties>
    <util:set id="set" set-class="java.util.HashSet">
        <value>I can't believe I get to see your face</value>
        <ref bean="lyricHolder"/>
    </util:set>
    <util:list id="list" list-class="java.util.ArrayList">
        <value>You've been working and I've been waiting</value>
        <ref bean="lyricHolder"/>
    </util:list>
</beans>

@Service("injectCollection")
public class CollectionInjection {
    @Resource(name="map")
    private Map<String, Object> map;
    @Resource(name="props")
    private Properties props;
    @Resource(name="set")
    private Set set;
    @Resource(name="list")
    private List list;
    public static void main(String... args) {
        GenericXmlApplicationContext ctx =
            new GenericXmlApplicationContext();
        ctx.load("classpath:spring/app-context-annotation.xml");
        ctx.refresh();
        CollectionInjection instance = (CollectionInjection)
            ctx.getBean("injectCollection");
        instance.displayInfo();
        ctx.close();
    }
    ...
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
@Service("injectCollection")
public class CollectionInjection {
    @Autowired
    @Qualifier("map")
    private Map<String, Object> map;
...
}

注入Collections

public class Singer {
    private String lyric = "I played a quick game of chess with the salt
                and pepper shaker";
    public void sing() {
            //commented because it pollutes the output
        //System.out.println(lyric);
    }
}

public interface DemoBean {
    Singer getMySinger();
    void doSomething();
}

public class StandardLookupDemoBean
          implements DemoBean {
        private Singer mySinger;
        public void setMySinger(Singer mySinger) {
                this.mySinger = mySinger;
        }
        @Override
        public Singer getMySinger() {
                return this.mySinger;
        }
        @Override
        public void doSomething() {
                mySinger.sing();
        }
}

public abstract class AbstractLookupDemoBean
     implements DemoBean {
    public abstract Singer getMySinger();
     @Override
     public void doSomething() {
         getMySinger().sing();
     }
}

<beans>
    <bean id="singer" class="com.apress.prospring5.ch3.Singer"
          scope="prototype"/>
    <bean id="abstractLookupBean"
        class="com.apress.prospring5.ch3.AbstractLookupDemoBean">
        <lookup-method name="getMySinger" bean="singer"/>
    </bean>
    <bean id="standardLookupBean"
        class="com.apress.prospring5.ch3.StandardLookupDemoBean">
        <property name="mySinger" ref="singer"/>
    </bean>
</beans>

import org.springframework.context.support.GenericXmlApplicationContext;
import org.springframework.util.StopWatch;
public class LookupDemo {
    public static void main(String... args) {
        GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();
        ctx.load("classpath:spring/app-context-xml.xml");
        ctx.refresh();
        DemoBean abstractBean = ctx.getBean("abstractLookupBean",
                  DemoBean.class);
        DemoBean standardBean = ctx.getBean("standardLookupBean",
                  DemoBean.class);
        displayInfo("abstractLookupBean", abstractBean);
        displayInfo("standardLookupBean", standardBean);
        ctx.close();
    }
    public static void displayInfo(String beanName, DemoBean bean) {
        Singer singer1 = bean.getMySinger();
        Singer singer2 = bean.getMySinger();
        System.out.println("" + beanName + ": Singer Instances the Same? "
                + (singer1 == singer2));
        StopWatch stopWatch = new StopWatch();
        stopWatch.start("lookupDemo");
        for (int x = 0; x < 100000; x++) {
            Singer singer = bean.getMySinger();
            singer.sing();
        }
        stopWatch.stop();
        System.out.println("100000 gets took "
              + stopWatch.getTotalTimeMillis() + " ms");
    }
}

方法注入，以及单元测试

@Component("singer)
@Scope("prototype")
public class Singer {
    private String lyric = "I played a quick game of chess
            with the salt and pepper shaker";
    public void sing() {
        // commented to avoid console pollution
        //System.out.println(lyric);
    }
}

import org.springframework.beans.factory.annotation.Lookup;
import org.springframework.stereotype.Component;
@Component("abstractLookupBean")
public class AbstractLookupDemoBean implements DemoBean {
    @Lookup("singer")
    public Singer getMySinger() {
        return null; // overriden dynamically
    }
    @Override
    public void doSomething() {
        getMySinger().sing();
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;
@Component("standardLookupBean")
public class StandardLookupDemoBean implements DemoBean {
        private Singer mySinger;
        @Autowired
        @Qualifier("singer")
        public void setMySinger(Singer mySinger) {
                this.mySinger = mySinger;
        }
        @Override
        public Singer getMySinger() {
                return this.mySinger;
        }
        @Override
        public void doSomething() {
                mySinger.sing();
        }
}

方法注入

public class ReplacementTarget {
    public String formatMessage(String msg) {
        return "<h1>" + msg + "</h1>";
    }
    public String formatMessage(Object msg) {
        return "<h1>" + msg + "</h1>";
    }
}

import org.springframework.beans.factory.support.MethodReplacer;
import java.lang.reflect.Method;
public class FormatMessageReplacer
          implements MethodReplacer {
        @Override
        public Object reimplement(Object arg0, Method method, Object... args)
                        throws Throwable {
                if (isFormatMessageMethod(method)) {
                        String msg = (String) args0;
                        return "<h2>" + msg + "</h2>";
                } else {
                    throw new IllegalArgumentException("Unable to reimplement method "
                        + method.getName());
                }
        }
        private boolean isFormatMessageMethod(Method method) {
                if (method.getParameterTypes().length != 1) {
                        return false;
                }
                if (!("formatMessage".equals(method.getName()))) {
                        return false;
                }
                if (method.getReturnType() != String.class) {
                        return false;
                }
                if (method.getParameterTypes()[0] != String.class) {
                        return false;
                }
                return true;
        }
}

<beans>
    <bean id="methodReplacer"
        class="com.apress.prospring5.ch3.FormatMessageReplacer"/>
    <bean id="replacementTarget"
        class="com.apress.prospring5.ch3.ReplacementTarget">
        <replaced-method name="formatMessage" replacer="methodReplacer">
            <arg-type>String</arg-type>
        </replaced-method>
    </bean>
    <bean id="standardTarget"
        class="com.apress.prospring5.ch3.ReplacementTarget"/>
</beans>

方法替代