三种定义bean的方式

方法一：基于XML的bean定义（需要提供setter方法）

1.首先编写student.java和teacher.java两个类

Student.java:

public class Student {

private String name;

private Teacher teacher;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Teacher getTeacher() {
return teacher;
}

public void setTeacher(Teacher teacher) {
this.teacher = teacher;
}
}

Teacher.java

public class Teacher {

private String name;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

2.配置spring.xml基于XML的bean定义（需要提供setter方法）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

<bean id="student" class="test.Student">
<property name="name" value="张三"/> /设置属性值
<property name="teacher" ref="teacher"/>
</bean>

<bean id="teacher" class="test.Teacher">
<property name="name" value="李四"/> //设置属性值
</bean>
</beans>

方法二：基于注解的bean定义（不需要提供setter方法）

@Component("teacher")
public class Teacher {

@Value("李四")
private String name;

public String getName() {
return name;
}

}
@Component("student")
public class Student {

@Value("张三")
private String name;

@Resource
private Teacher teacher;

public String getName() {
return name;
}

public Teacher getTeacher() {
return teacher;
}

<?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.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">


<context:component-scan base-package="test"/>

</beans>

方法三：基于Java类的bean定义（需要提供setter方法）

@Configuration
public class BeansConfiguration {

@Bean
public Student student(){
Student student=new Student();
student.setName("张三");
student.setTeacher(teacher());
return student;
}

@Bean
public Teacher teacher(){
Teacher teacher=new Teacher();
teacher.setName("李四");
return teacher;
}

}

入口函数为：

public class Main {

public static void main(String args[]){
AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(BeansConfiguration.class);
Student student= (Student) context.getBean("student");
Teacher teacher= (Teacher) context.getBean("teacher");
System.out.println("学生的姓名："+student.getName()+"。老师是"+student.getTeacher().getName());
System.out.println("老师的姓名："+teacher.getName());
}

}

巴特西

三种定义bean的方式

最新文章

热门文章