Spring method injection method to replace

In the spring Ioc container, it is allowed to replace the method of another bean with the method of one bean.

public class ForestTwo implements MethodReplacer {

    public ForestTwo() {

      super ();

    }

    public Object reimplement(Object arg0, Method arg1, Object[] arg2)

         throws Throwable {

     Tree tt = new Tree();

     tt.setName( "Osmanthus" );

      return tt;

    }

}

  public class Forest {

    private Tree tree ;

    publicTree getTree () {

     Tree reTree = new Tree();

     reTree.setName( "willow tree" );

      return reTree;

    }

    public void setTree(Tree tree) {

      this . tree = tree;

    }

    public Forest () {

      super ();

    }

    public Forest(Tree tree) {

      super ();

      this . tree = tree;

    }

}

Arrangement one

      < bean id = "forest" class = "com.aowin.modle.Forest" > </bean>  

      < bean id = "forest2" class = "com.aowin.modle.ForestTwo" />

System. out .println( forest .getTree().getName());

The output is --- willow

Arrangement two

< bean id = "forest" class = "com.aowin.modle.Forest" >

      < replaced-method name = "getTree" replacer = "forest2" ></ replaced-method >

  </ bean >

              

  < bean id = "forest2" class = "com.aowin.modle.ForestTwo" />

System. out .println( forest .getTree().getName());

输出的是 桂花。

用于替换他人的Bean必须实现 MethodReplacer接口

因为 forest2 实现了  MethodReplacer 接口，重写了该接口下的  reimplement（）方法。

当  forest 调用getTree方法时，就会被 forest2替换掉，用 重写了的  reimplement（）方法去替换。