Spring Beans 自动装配使用XML配置列子（带源码）

原文地址：http://websystique.com/spring/spring-beans-auto-wiring-example-using-xml-configuration/

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Bean 装配是为了提供需要完成任务所依赖bean。Spring中，bean可以通过手动和自动两种方式装配。

手动装配 : 通过 <property> 或者 <constructor> 标签中的ref 属性

<!-- default example (autowire="no") -->
<bean id="driver" class="com.websystique.spring.domain.Driver"><property name="license" ref="license"/>
</bean><bean id="license" class="com.websystique.spring.domain.License" ><property name="number" value="123456ABCD"/>
</bean>

自动装配：使用<bean> 标签中的autowire

<bean id="application" class="com.websystique.spring.domain.Application" autowire="byName"/>

在此例中，bean将会通过Spring自动装配特性自动的装配。

有4种方式：

autowire="byName" : 根据属性名自动装配。如果另外一个bean属性名于此相同则自动装配。
autowire="byType" : 根据bean的类型进行自动装配。
autowire="constructor" : 根据构造方法装自动装配。如果其他bean的构造参数和此相同则此bean将被装配到其他bean的构造方法。
autowire="no" : 不自动装配。和通过ref指定一样。

1. autowire=”byName” 例子

package com.websystique.spring.domain;public class Application {private ApplicationUser applicationUser;public ApplicationUser getApplicationUser() {return applicationUser;}public void setApplicationUser(ApplicationUser applicationUser) {this.applicationUser = applicationUser;}@Overridepublic String toString() {return "Application [applicationUser=" + applicationUser + "]";}
}

package com.websystique.spring.domain;public class ApplicationUser {private String name;public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic String toString() {return "ApplicationUser [name=" + name + "]";}
}

<?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"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"><!-- byName example --><bean id="application" class="com.websystique.spring.domain.Application" autowire="byName"/><bean id="applicationUser" class="com.websystique.spring.domain.ApplicationUser" ><property name="name" value="superUser"/></bean></beans>

application类的applicationUser属性和 ApplicationUser bean的id相同。

package com.websystique.spring;import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.websystique.spring.domain.Application;public class AppMain {public static void main(String args[]){AbstractApplicationContext context = new ClassPathXmlApplicationContext("app-config.xml");//autowire=byName Application application = (Application)context.getBean("application");System.out.println("Application Details : "+application);}
}

运行结果：

Application Details : Application [applicationUser=ApplicationUser [name=superUser]]

2. autowire=”byType”例子

package com.websystique.spring.domain;public class Employee {private EmployeeAddress address;public EmployeeAddress getAddress() {return address;}public void setAddress(EmployeeAddress address) {this.address = address;}@Overridepublic String toString() {return "Employee [address=" + address + "]";}
}

package com.websystique.spring.domain;public class EmployeeAddress {private String Street;private String city;public String getStreet() {return Street;}public void setStreet(String street) {Street = street;}public String getCity() {return city;}public void setCity(String city) {this.city = city;}@Overridepublic String toString() {return "EmployeeAddress [Street=" + Street + ", city=" + city + "]";}
}

<?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"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"><!-- byType example --><bean id="employee" class="com.websystique.spring.domain.Employee" autowire="byType"/><bean id="employeeAddress" class="com.websystique.spring.domain.EmployeeAddress" ><property name="street" value="112/223,SantaVila"/><property name="city" value="Nebraska"/></bean></beans>

Employee 类中 EmployeeAddress address 和employeeAddress 并不相同，但是是按照类型注入。所以可以装配进去。

运行：

package com.websystique.spring;import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.websystique.spring.domain.Employee;public class AppMain {public static void main(String args[]){AbstractApplicationContext context = new ClassPathXmlApplicationContext("app-config.xml");//autowire=byTypeEmployee employee = (Employee)context.getBean("employee");System.out.println("Employee Details : "+employee);}
}

输出：

Employee Details : Employee [address=EmployeeAddress [Street=112/223,SantaVila, city=Nebraska]]

3. autowire=”constructor”

package com.websystique.spring.domain;public class Performer {private Instrument instrument;public Performer(Instrument instrument){this.instrument = instrument;}@Overridepublic String toString() {return "Performer [instrument=" + instrument + "]";}
}

package com.websystique.spring.domain;public class Instrument {private String name;public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic String toString() {return "Instrument [name=" + name + "]";}
}

注意：Performer类有一个接收Instrument类型的参数的构造方法。

XML配置文件：

<?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"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"><!-- constructor example --><bean id="performer" class="com.websystique.spring.domain.Performer" autowire="constructor"/><bean id="instrument" class="com.websystique.spring.domain.Instrument" ><property name="name" value="PIANO"/></bean></beans>

Performer<span style="font-weight: bold;"><span style="font-family:Consolas, Bitstream Vera Sans Mono, Courier New, Courier, monospace;"><span style="font-size: 13px; line-height: 14.3px; white-space: pre; background-color: rgb(245, 245, 245);"><span style="color:#0000ff;"><span style="color: rgb(64, 64, 64); font-family: 'Open Sans', sans-serif; font-size: 15px; line-height: 22.5px;">类有一个接收Instrument类型的参数的构造方法。将在Spring 定义的id为instrument的装配进去，。</span></span></span></span></span>

<pre name="code" class="java">package com.websystique.spring;import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.websystique.spring.domain.Performer;public class AppMain {public static void main(String args[]){AbstractApplicationContext context = new ClassPathXmlApplicationContext("app-config.xml");//autowire=constructorPerformer performer = (Performer)context.getBean("performer");System.out.println("Performer Details : "+performer);}}

运行结果：

<pre name="code" class="plain">Performer Details : Performer [instrument=Instrument [name=PIANO]]

3. autowire=”no”

<pre name="code" class="java">package com.websystique.spring.domain;public class Driver {private License license;public void setLicense(License license) {this.license = license;}public License getLicense() {return license;}@Overridepublic String toString() {return "Driver [license=" + license + "]";}
}

package com.websystique.spring.domain;public class License {private String number;public String getNumber() {return number;}public void setNumber(String number) {this.number = number;}@Overridepublic String toString() {return "License [number=" + number + "]";}}

配置文件：

<?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"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"><!-- default example (autowire="no") --><bean id="driver" class="com.websystique.spring.domain.Driver" autowire="no"><property name="license" ref="license"/></bean><bean id="license" class="com.websystique.spring.domain.License" ><property name="number" value="123456ABCD"/></bean></beans>

autowire="no" 没有什么作用。可以不写。只是不自动装载。

运行：

package com.websystique.spring;import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import com.websystique.spring.domain.Driver;public class AppMain {public static void main(String args[]){AbstractApplicationContext context = new ClassPathXmlApplicationContext("app-config.xml");//autowire=defaultDriver driver = (Driver)context.getBean("driver");System.out.println("Driver Details : "+driver);}
}

结果：

Driver Details : Driver [license=License [number=123456ABCD]]

下载地址：http://websystique.com/?smd_process_download=1&download_id=785