spring da-y02-go1
使用构造器实例化bean:
springday02:(同样导入5个基本jar包)
1.复制xml文件到ioc包下
2.B类,实现无参构造器
3.A类,B是它的成员变量,实现无参和set/get方法
4.修改xml中,实现构造器实例化bean,注意,因为A类中使用到了B对象,所以需要ref属性
5.测试
A.java:
package container.ioc;
public class A {
private B b;
public B getB() {
return b;
}
public void setB(B b) {
this.b = b;
}
public A(){
System.out.println("A的无参构造器");
}
public A(B b){
this.b = b;
}
}
B.java:
package container.ioc;
public class B {
public B(){
System.out.println("B的无参构造器");
}
}
xml:
<bean id="b1" class="container.ioc.B" />
<bean id="a1" class="container.ioc.A">
<constructor-arg index="0" ref="b1"></constructor-arg>
</bean>
TestCase:
package container.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestCase {
@Test
public void test1(){
String cfg = "container/ioc/applicationContext.xml";
ApplicationContext ac =
new ClassPathXmlApplicationContext(cfg);
A a = ac.getBean("a1",A.class);
System.out.println(a);
}
}
测试结果: