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Springframework constructor-arg

开发者 https://www.devze.com 2023-04-10 02:19 出处:网络
I have a MainClass which have 2 variables.I would like to pass those 2 values to a springframework bean class \"Test\".how do I define that in applicationContext.xml and also how do I pass those 2 var

I have a MainClass which have 2 variables. I would like to pass those 2 values to a springframework bean class "Test". how do I define that in applicationContext.xml and also how do I pass those 2 variable values to the bean "Test".

Ex:

class MainClass {
       public int var1;
      public int var2;
      public Test test;

   public void setVar1(int var11) {
    var1 = var11;
   }

    public void setVar2(int var22) {
        var2 = var22;
    }

   public static void main(String args[]) {

       ApplicationContext context = 
           new FileSystemXmlApplicationContext("applicationContext.xml");
      Test = context.getBean("test");
   }
  }

------------ TEST class ------------

public class Test {

 public Test (int var1, int var2) {}
}

------------- applicationContext.xml -------------

   <bean id="test" c开发者_JS百科lass="com.path.test">
       <constructor-arg index="0" type="int" value="????"/>
       <constructor-arg index="1" type="int" value="????"/>
   </bean>


You can pass values in like this:

<bean id="test" class="com.path.test.Test">
   <constructor-arg index="0" type="int" value="123"/>
   <constructor-arg index="1" type="int" value="456"/>
</bean>

You should remember to put your fully-qualified class name as the value of the class attribute.

That said, your Test class is not holding onto its state. If you want to get a hold of the values you specified in your applicationContext.xml, you should create some members of Test:

public class Test {
    private int v1;
    private int v2;

    public Test (int var1, int var2) {v1 = var1; v2 = var2;}

    public int getVOne() {
        return v1;
    }

    public int getVTwo() {
        return v2;
    }
}

You should then be able to access these in your main method like this:

public static void main(String args[]) {

    ApplicationContext context = 
       new FileSystemXmlApplicationContext("applicationContext.xml");
    Test test = context.getBean("test");
    int v1 = test.getVOne();
    int v2 = test.getVTwo();

    System.out.println("V1: " + v1 + " V2: " + v2); //output: V1: 123 V2: 456
}


As Nicholas says, it's a bit of a weird thing to do, but you could achieve it using PropertyPlaceholderConfigurer.

Something like this:

 public static void main(String args[]) {
        PropertyPlaceholderConfigurer configurer = new PropertyPlaceholderConfigurer();
        Properties properties = new Properties();
        properties.setProperty("var1", Integer.toString(var1));
        properties.setProperty("var2", Integer.toString(var2));
        configurer.setProperties(properties);

        FileSystemXmlApplicationContext context = new FileSystemXmlApplicationContext();
        context.addBeanFactoryPostProcessor(configurer);

        context.setConfigLocation("applicationContext.xml");
        context.refresh();
        Test test = (Test) context.getBean("test");
 }

NOTE: var1 and var2 should be static if you want to reference them from main()

Then reference the placeholders like so:

<bean id="test" class="com.path.test">
   <constructor-arg index="0" type="int" value="${var1}"/>
   <constructor-arg index="1" type="int" value="${var2}"/>
</bean>

See also this forum thread: http://forum.springsource.org/showthread.php?71815-Passing-Bean-properties-using-java.util.Properties

API doc: http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.html

HTH

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