其实注入null空值很简单,但偏偏总有人写不对,下面写一个简单的小实例 实体类: public class PersonServiceBean { private String name; private String sex; private Integer age; private Date birth; public PersonServiceBean() { super(); // Todo Auto-generated constructor stub System.out.println("构造器初始化对象"); } public PersonServiceBean(String name,String sex,Integer age,Date birth) { super(); this.name = name; this.sex = sex; this.age = age; this.birth = birth; } public void setName(String name) { System.out.println("name的set方法------------"+name); this.name = name; } public void setSex(String sex) { this.sex = sex; } public void setAge(Integer age) { this.age = age; } public void setBirth(Date birth) { this.birth = birth; } @Override public String toString() { return "PersonServiceBean [name=" + name + ",sex=" + sex + ",age=" + age + ",birth=" + birth + "]"; } } Xml文件 <?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-2.5.xsd"> <bean id="personServiceBean" class="cn.csdn.hr.service.PersonServiceBean"> <property name="birth"> <null></null> </property> </bean> </beans> 这样就可以了,但是偏偏有人总是在<property name="birth"> 中加上一个value=”null”,就是想不起来有一个null标签,要说的是如果不写<property name="XXX"></property>,注入的也会是空值哟 测试方法 @Test public void test() { //第一步:获取应用程序上下文对象 ApplicationContext ac=new ClasspathXmlApplicationContext("classpath:beanNull.xml"); //第二步:根据应用程序上下文对象的getBean(id名称)方法获取实例bean对象 PersonServiceBean p=(PersonServiceBean) ac.getBean("personServiceBean"); System.out.println(p.toString()); } 结果: 构造器初始化对象 PersonServiceBean [name=null,sex=null,age=null,birth=null]
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