初始Spring框架

Posted 2020-10-11 努力奋斗吧

Spring入门案例的步骤;
    1.找依赖
       spring-beans.4.2.0.jar
            附带了core核心 和commons-logging
       spring-context.4.2.0.jar
               spring-expression.4.2.0.jar
               spring-aoplple.4.2.0.jar
               spring-aop.4.2.0.jar
    2.HappyService类型
 
    3 beans 根节点下有N个bean节点
      <bean id="service" class="类型的全名">

    4.容器
    ApplicationContext ctx=new  ClassPathXmlApplicationContext("applictionContext.xml");
        HappyService service=  (HappyService)ctx.getBean("service");

下面我们写一个例子：

实体类：

private String info;
private Integer age;

public Integer getAge() {
    return age;
}
public void setAge(Integer age) {
    this.age = age;
}

public void setInfo(String info) {
    this.info = info;
}
public String getInfo() {
    return info;
}

@Override
public String toString() {
    return "HappyService{" +
            "info=\'" + info + \'\\\'\' +
            ", age=" + age +
            \'}\';
}


applicationContext.xml文件：
<!--IOC  控制反转--> 

<bean id="happyService" class="cn.happy.day01.HappyService">
<!--DI  依赖-->
   <property name="info" value="李四"></property>
    <property name="age" value="20"></property>
</bean>

测试类：

@Test
public void Test(){
    //Spring容器
    ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
    //返回值必须进行强转
    HappyService bean = (HappyService)context.getBean("happyService");
    System.out.println(bean);
}


结果如下：