<!--?xml version="1.0" encoding="UTF-8"?-->
<!-- 定义约束文件 -->（标注）
<!-- ELEMENT 表示元素 -->
<!-- ATTLIST 表示属性 -->
<!-- CDATA 表示字符串类型 -->
<!-- REQUIRED 表示此属性必须的写 -->
<!-- *代表多个 -->
<!-- IMPLIED 表示此属性可写 -->
<!-- redirect 重定向或转发 -->
 
 
  <!--ELEMENT actions (action)-->
  <!--ELEMENT action (result*)-->（*表示可以多个）
   
  <!--ATTLIST action name CDATA #REQUIRED
           class CDATA #REQUIRED
    -->
  <!--ATTLIST RESULT name CDATA #IMPLIED
     redirect (true|false) "false"
  -->
]>
<framework>
  <!-- 进行测试 -->
<actions>
  <action name="loginAction" class="cn.hq.Action.LoginAction">
  <result name="success">success.jsp</result>
  <result name="login">index.jsp</result>
  </action>
</actions>
</framework>

/*
 * action节点不止一个
 * 用来来管理ActionMapping类
 */
public class ActionMappingManager {
  //actionMapping类的集合
  private Map<String,ActionMapping> maps=new HashMap<String,ActionMapping>();
   
  public ActionMapping getActionMapping(String name)
  {
     return maps.get(name);
  }
   
  //解析在src项目下的所有配置文件
  //实例化完毕后进行解析
  public ActionMappingManager(String[] file){
    for (String filename : file) {
      Init(filename);
    }
  }
  //init初始化方法
  //解析xml文档
  public void Init(String path){
     
    try {
       InputStream is=this.getClass().getResourceAsStream("/"+path);
       //解析xml
       Document doc=new SAXReader().read(is);
       //获取根节点
       Element root = doc.getRootElement();
       //获取actions节点
       Element actions=(Element)root.elementIterator("actions").next();
       //使用for循环来遍历actions节点下的所有action节点
       for(Iterator<Element> action=actions.elementIterator("action");action.hasNext();)
       {
         //获取到<action>节点
         Element actionnext = action.next();
         //分别获取到action节点中的name属性和class属性
         String name = actionnext.attributeValue("name");
         String classname = actionnext.attributeValue("class");
         //将以上两个属性保存到ActionMapping类中
         ActionMapping mapp=new ActionMapping();
         mapp.setClassname(classname);
         mapp.setName(name);
         //由于一个action节点下有多个result节点 遍历action下所有的result节点
         for(Iterator<Element> result=actionnext.elementIterator("result");result.hasNext();)
         {
           //获取到result节点
           Element resultnext = result.next();
           //提取result节点的name属性值和result节点中的值
           String resultname = resultnext.attributeValue("name");
           String resultvalue=resultnext.getText();
           //将其分别存入到actionMapping中的双列集合中去，方便调用actionMapping类(actionMapping类中就有数据了!)
           mapp.addResult(resultname, resultvalue);
           System.out.println(mapp.getName());
         }
         //得到所有action节点的集合
         maps.put(mapp.getName(), mapp);
       }
        
    } catch (Exception e) {
      // TODO: handle exception
    }
   }
  }

public class ActionManager {
 
  public static Action getActionClass(String classname)
  {
    Class clazz=null;
    Action action=null;
    //获取当前线程的类加载器
    try {
      //如果线程中的有那么一个类，直接根据类名获取该类的类型
      clazz=Thread.currentThread().getContextClassLoader().loadClass(classname);
    } catch (ClassNotFoundException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    if(clazz==null)
    {
      try {
        //如果该线程中没有，那么使用class.forname方法获取
        clazz=Class.forName(classname);
      } catch (ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }
    if(action==null)
    {
      try {
        //将获取到的类型转换为action，调用无参构造函数，某种程度上相当于new，不过new需要指定类型
        action=(Action)clazz.newInstance();
      } catch (InstantiationException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }
    return action;
  }
}　

public class MyServlet extends HttpServlet {
 
  /**
   *你很菜
   */
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
 
    doPost(request, response);
  }<br>
  /**
   *继续努力
   */
  ActionMappingManager man=null;
  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
     
    //获取ActionMapping对象
    ActionMapping actionMapping = man.getActionMapping(getPath(request));
    //获取action接口反射机制
    Action action = ActionManager.getActionManager(actionMapping.getClassname());
     
    try {
      String message=action.execute(request, response);
      String results = actionMapping.getResults(message);
       
      response.sendRedirect(results);
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
   
  /*
   * 获取请求的路径名
   */
  public String getPath(HttpServletRequest request){
    //项目+请求地址
    String requestURI = request.getRequestURI();
    //项目名称
    String contextPath = request.getContextPath();
    //具体请求
    String path = requestURI.substring(contextPath.length());
    String filename = path.substring(1,path.lastIndexOf("."));
     
    return filename;
  }
  /*
   *重写init,程序运行加载所有类
   *
   */
  @Override
  public void init(ServletConfig config) throws ServletException {
 
    //config对象是javax.servlet.ServletConfig的对象，功能是获得初始化配置信息
    //config.getInitParameter是取得指定名称的初始化参数内容
    String filename = config.getInitParameter("config");
    String [] filenames=null;
    if(filename==null){
      //如果为空 ,
      filenames=new String[]{"Framework.xml"};
    }else{
      //若果有其他的配置参数信息，那么以，分隔存入数组中
      filenames=filename.split(",");
    }
    //使用init方法进行初始化
    man=new ActionMappingManager(filenames);
  }
}

public class LoginAction implements Action{
 
  @Override
  public String execute(HttpServletRequest request,
      HttpServletResponse response) throws Exception {
     
    String name = request.getParameter("name");
    String pwd = request.getParameter("pwd");
    if(name.equals("1")&&pwd.equals("1")){
      return SUCCESS;
    }else{
      return LOGIN;
    } 
  }
}