spring 方法注入之 方法以替换

在spring Ioc 容器里，允许用一个Bean 的方法去替换另一个Bean 的方法。

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( "桂花" );

      return tt;

    }

}

  public class Forest {

    private Tree tree ;

    public Tree getTree() {

     Tree reTree = new Tree();

     reTree.setName( "柳树" );

      return reTree;

    }

    public void setTree(Tree tree) {

      this . tree = tree;

    }

    public Forest() {

      super ();

    }

    public Forest(Tree tree) {

      super ();

      this . tree = tree;

    }

}

配置一

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

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

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

输出的是---柳树

配置二

< 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。