spring bean初始化

声明角色bean

public class Roles{
  private int id;
  private String roleName;

  private Roles(){}
  private Roles(int id , String roleName){
      this.id = id;
      this.roleName = roleName;
  }
    @Override
    public String toString(){
      return "Users [ id=" + id + ",name=" + roleName + "]" ; 
    }
}

spring配置

<bean id="roles" class="cn.com.ztz.spring.model.Roles">  
    <constructor-arg value="1"/>  
    <constructor-arg value="管理员"/>  
</bean>  

测试

public class SpringTest {  
    public static void main(String[] args) {  
       ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");  
        Roles u = (Roles)context.getBean("roles");  
        System.out.println(u.toString());  
    }  
}

=========================================================

Roles.java
public class Roles {  
    private int id;  
    private String roleName;  
    //用户  
    private Users users;  
      
    public Roles() {  
    }  
    public Roles(int id,String roleName,Users users) {  
        this.id=id;  
        this.roleName = roleName;  
        this.users=users;  
    }  
    //重写toString方法，方便测试  
    @Override  
    public String toString() {  
        return "Roles [id=" + id + ", roleName=" + roleName + ", users="  
                + users + "]";  
    }  
}  

用户bean
public class Users {
private int id;
private String name;
public Users(){

    }  
    public Users(int id, String name) {  
        this.id = id;  
        this.name = name;  
    }  
    @Override  
    public String toString() {  
        return "Users [id=" + id + ", name=" + name + "]";  
    }  
}   

配置

<bean id="roles" class="cn.com.ztz.spring.model.Roles">  
    <constructor-arg value="1"/>  
    <constructor-arg value="管理员"/>  
    <constructor-arg ref="users"/>  
</bean>  
<bean id="users" class="cn.com.ztz.spring.model.Users">  
    <constructor-arg value="2"/>  
    <constructor-arg value="张三"/>  
</bean>  

若要在Roles中引入Users,在Spring中就要用<constructor-arg ref=""/>指定资源

转载于:https://www.jianshu.com/p/a8e76e4bdfb4