Spring自动安装（autowire）麻烦吗？（二）

Spring自动装配（autowire）麻烦吗？（二）

??? 在上一篇文章文本太长介绍了一下Spring自动装配（autowire）的三个属性，还有三个属性这里介绍。

//spring中 app.xml的设置<bean id="empServiceImpl" autowire="constructor" ><!— 如果autowire="constructor"在HourEmpServiceImpl 类中没有通过构造器赋值，那么empServiceImpl= null。但是如果有构造器赋值，在xml中没有声明那么就会出现bug：org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'hourEmpServiceImpl' defined in class path resource [app.xml]: Unsatisfied dependency expressed through constructor argument with index 0 of type [com.csdn.service.EmpServiceImpl]: : No unique bean of type [com.csdn.service.EmpServiceImpl] is defined: Unsatisfied dependency of type [class com.csdn.service.EmpServiceImpl]: expected at least 1 matching bean; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [com.csdn.service.EmpServiceImpl] is defined: Unsatisfied dependency of type [class com.csdn.service.EmpServiceImpl]: expected at least 1 matching beanat org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:591)at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:193)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:925)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:835)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:440)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)at java.security.AccessController.doPrivileged(Native Method)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:429)at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:728)at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:380)at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)at com.csdn.junit.EmpTest.test(EmpTest.java:13)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)at java.lang.reflect.Method.invoke(Method.java:597)at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)at org.junit.runners.ParentRunner.run(ParentRunner.java:220)at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [com.csdn.service.EmpServiceImpl] is defined: Unsatisfied dependency of type [class com.csdn.service.EmpServiceImpl]: expected at least 1 matching beanat org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:613)at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:622)at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:584)... 42 more--></bean>//empServiceImpl的代码package com.csdn.service;public class EmpServiceImpl {/**定义一个变量实例*/private String name;/**通过set方法进行赋值*/public void setName(String name) {this.name = name;}}// hourEmpServiceImpl的代码package com.csdn.service;public class HourEmpServiceImpl {/**定义一个EmpServiceImpl的操作对象*/private EmpServiceImpl empServiceImpl;/**通过构造器实现赋值*/public HourEmpServiceImpl(EmpServiceImpl empServiceImpl) {this.empServiceImpl = empServiceImpl;}}//junit测试类代码 @Testpublic void test(){ApplicationContext ac = new ClassPathXmlApplicationContext("app.xml");HourEmpServiceImpl hsi=(HourEmpServiceImpl) ac.getBean("hourEmpServiceImpl"); }

//spring中 app.xml的设置<bean id="empServiceImpl" autowire=" autodetect" ><!—autowire的定义为autodetect首先尝试 constructor来自动装配，然后使用byType方式--></bean>//empServiceImpl的代码package com.csdn.service;public class EmpServiceImpl {/**定义一个变量实例*/private String name;/**通过set方法进行赋值*/public void setName(String name) {this.name = name;}}// hourEmpServiceImpl的代码package com.csdn.service;public class HourEmpServiceImpl {/**定义一个EmpServiceImpl的操作对象*/private EmpServiceImpl empServiceImpl;/**构造器赋值*/public HourEmpServiceImpl(EmpServiceImpl empServiceImpl) {System.out.println("构造器赋值");this.empServiceImpl = empServiceImpl;}/**生成相应的set方法通过set方法注入的*/public void setEmpServiceImpl(EmpServiceImpl empServiceImpl) {System.out.println("set方法赋值");this.empServiceImpl = empServiceImpl;}}//junit测试类代码 @Testpublic void test(){ApplicationContext ac = new ClassPathXmlApplicationContext("app.xml");HourEmpServiceImpl hsi=(HourEmpServiceImpl) ac.getBean("hourEmpServiceImpl"); }

<?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-2.5.xsd"default-autowire="byName"><bean id="empServiceImpl" autowire=" default "><!—这个bean的autowire属性的值为上一级跟标签的值--></bean></beans>//empServiceImpl的代码package com.csdn.service;public class EmpServiceImpl {/**定义一个变量实例*/private String name;/**通过set方法进行赋值*/public void setName(String name) {this.name = name;}}// hourEmpServiceImpl的代码package com.csdn.service;public class HourEmpServiceImpl {/**定义一个EmpServiceImpl的操作对象*/private EmpServiceImpl empServiceImpl;/**生成相应的set方法通过set方法注入的*/public void setEmpServiceImpl(EmpServiceImpl empServiceImpl) {this.empServiceImpl = empServiceImpl;}}//junit测试类代码 @Testpublic void test(){ApplicationContext ac = new ClassPathXmlApplicationContext("app.xml");HourEmpServiceImpl hsi=(HourEmpServiceImpl) ac.getBean("hourEmpServiceImpl"); }

?以上只用于spring2.5.6版本

Spring自动安装（autowire）麻烦吗？（

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