Question

我有一个简单的名为HelloWorld的spring项目，并尝试从applicationContext.xml文件加载两个属性，但属性不会在相应的setter中设置。

的pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>3.2.4.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>3.2.4.RELEASE</version>
    </dependency>
</dependencies>

主要方法：

public class MyApp {

public static void main(String[] args) {
    ClassPathXmlApplicationContext context = new 
    ClassPathXmlApplicationContext("applicationContext.xml");
    TrackCoach trackCoach = context.getBean("myCoach", TrackCoach.class);
    trackCoach.getDailyWorkout();
    System.out.println(trackCoach.getName());
    System.out.println(trackCoach.getFamily());
    }
}

TrackCoach.java

public class TrackCoach {
private String name;
private String family;

public String getName() {
    return name;
}

public void setName(String name) {
    System.out.println("name is set");
    this.name = name;
}

public String getFamily() {
    return family;
}

public void setFamily(String family) {
    System.out.println("family is set");
    this.family = family;
}

public void getDailyWorkout() {
    System.out.println("track coach!");
    }
}

的applicationContext.xml

    <?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-3.0.xsd">

    <bean id="myCoach" class="TrackCoach">
        <property name="name" value="Jhon"/>
        <property name="family" value="Goo"/>
    </bean>

</beans>

输出结果为：

track coach! null null

Answer 1

在定义bean时应该给出完整的类名，例如类com.test包中存在TrackCoach然后它就像 com.test.TrackCoach

<bean id="myCoach" class="com.test.TrackCoach">

Answer 2

我在applicationContext.xml文件中看到了许多问题：

您发布的pom.xml具有两次相同的依赖关系。要运行spring基本示例，您需要spring-core jar以及spring-context jar。

定义spring-context名称空间。如果需要，您可以指向特定版本的xsd。虽然截至目前您还没有使用任何与上下文相关的标签，但对于大多数弹簧基本情况，您将需要它。

 <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">

您应该使用完全限定的类名来标识该类。使用包来分类。

  <bean id="myCoach" class="com.beans.TrackCoach">
     <property name="name" value="Jhon"/>
     <property name="family" value="Goo"/>
 </bean>

为什么特定bean类的`applicationContext.xml`中定义的属性没有设置？

2 个答案: