Spring中Bean的5种自动装载模式

在Spring中，有五种autowire模式：byName,byType,constructor,autodetect,no;
下面分别对其进行介绍
1 byName:这个很简单，直接按照名字进行查找

package com.jnotnull;

public class HelloWorld {
public String message = null;

public void init(){
this.message = "HelloWorld";
}

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}

}

config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld" autowire="byName">
<property name ="message">
<value>HelloWorld</value>
</property>
<bean>
</beans>

2 byType：按照类型进行查找，如果没有找到匹配的，则什么也没有改变，同时可以通过设置dependency-check="objects"属性来在没有匹配到的情况下抛出这种错误。

package com.jnotnull;

public class HelloWorld {
public String message = null;

public void init(){
this.message = "HelloWorld";
}

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}

}

config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld" autowire="byType">
<property name ="message">
<value>HelloWorld</value>
</property>
<bean>
</beans>


3 constructor：直接根据构造函数进行匹配

package com.jnotnull;

public class HelloWorld {
public String message = null;

public void init(){
this.message = "HelloWorld";
}

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}

}

config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld" autowire="constrator">
<property name ="message">
<value>HelloWorld</value>
</property>
<bean>
</beans>

4 autodetect：先按constructor匹配，再按byType匹配

package com.jnotnull;

public class HelloWorld {
public String message = null;

public void init(){
this.message = "HelloWorld";
}

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}

}

config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld" autowire="autodetect">
<property name ="message">
<value>HelloWorld</value>
</property>
<bean>
</beans>


5 no：不用任何模式进行匹配，这个也是默认的匹配模式

package com.jnotnull;

public class HelloWorld {
public String message = null;

public void init(){
this.message = "HelloWorld";
}

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}

}

config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans Public "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id ="HelloWorld" class="com.jnotnull.HelloWorld" autowire="no">
<property name ="message">
<value>HelloWorld</value>
</property>
<bean>
</beans>

通过上面的介绍，你是不是发现很简单。