spring入门（8）装配Bean之自动装配

spring入门（8）装配Bean之自动装配2013-07-18 csdn 史国旭Spring_Autowiring collaborators

在Spring3.2.2中自动装配类型，分别为：no（default）（不采用自动装配）、byName，byType，constructor下面来分别介绍一下这些是如何自动装配的

Mode Explanation

no: （Default） No autowiring. Bean references must be defined via a ref element.

Changing the default setting is not recommended for larger deployments,

because specifying collaborators explicitly gives greater control and clarity.

To some extent, it documents the structure of a system.

byName:Autowiring by property name.

Spring looks for a bean with the same name as the property that needs to be autowired.

For example, if a bean definition is set to autowire by name,

and it contains a master property （that is, it has a setMaster（..） method）,

Spring looks for a bean definition named master, and uses it to set the property.

byType:Allows a property to be autowired if exactly one bean of the property type exists in the container.

If more than one exists, a fatal exception is thrown,

which indicates that you may not use byType autowiring for that bean.

If there are no matching beans, nothing happens; the property is not set.

constructor：Analogous to byType, but applies to constructor arguments.

If there is not exactly one bean of the constructor argument type in the container, a fatal error is raised

案例分析：

1、创建CumputerBean类

package www.csdn.spring.autowire.bean;public class CumputerBean {// 电脑名称 private String name;public void setName（String name） {this.name = name;}}

package www.csdn.spring.autowire.bean;public class CumputerBean {// 电脑名称private String name;public void setName（String name） {this.name = name;}}

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