Spring Beans 自动装配 使用XML配置列子（带源码）

时间: 2020-11-26｜39次围观｜0 条评论

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

【项目代码，在文章末尾提供下载地址】

【翻译 by  明明如月 QQ 605283073】


上一篇：Spring 4 Hello World 例子（带源码）

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;
    }
 
    @Override
    public 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;
    }
 
    @Override
    public 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.xsd
                            http://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;
    }
 
    @Override
    public 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;
    }
 
    @Override
    public 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.xsd
                            http://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=byType
        Employee 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;
    }
 
    @Override
    public 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;
    }
 
    @Override
    public 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.xsd
                            http://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=constructor
        Performer 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;
    }
 
    @Override
    public 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;
    }
 
    @Override
    public 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.xsd
                            http://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=default
        Driver 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


原文链接：https://blog.csdn.net/w605283073/article/details/51435289


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