仿写 Lite Struts

//使用dom4j.jar


0. 读取配置文件struts.xml

1. 根据actionName找到相对应的class ， 例如LoginAction,   通过反射实例化（创建对象）
据parameters中的数据，调用对象的setter方法， 例如parameters中的数据是 
("name"="test" ,  "password"="1234") ,      
那就应该调用 setName和setPassword方法

2. 通过反射调用对象的exectue 方法， 并获得返回值，例如"success"

3. 通过反射找到对象的所有getter方法（例如 getMessage）,  
通过反射来调用， 把值和属性形成一个HashMap , 例如 {"message":  "登录成功"} ,  
放到View对象的parameters

4. 根据struts.xml中的 <result> 配置,以及execute的返回值，  确定哪一个jsp，  
放到View对象的jsp字段中。

一、涉及内容：

反射，XML

二、写后感：

　　顺便了解下struts，通过XML创建Action，更能理解反射作用，体现Java动态性。由此想到之前学过的SSH，也能猜想大概底层创建对象，加深理解。

　　写的时候还是觉得有点乱，最后封装和函数命名都乱了，（风中凌乱。。。/(ㄒoㄒ)/~~）写框架也是慢慢积累的。

三、上代码

//Struts.java
public class Struts {

    public static View runAction(String actionName, Map<String,String> parameters) {
        Element  rootElement = null;
        try {
            /**
             * 0.读取配置文件
             */
            rootElement = readStrutsXml().getRootElement();
        } catch (DocumentException e) {
            e.printStackTrace();
        }

        /**
         * 1.根据actionName找到class
         * 并设置
         */
        String classPath = findClass(actionName, rootElement);

        return handle(classPath, parameters, rootElement);
    }

    private static Document readStrutsXml() throws DocumentException {
        SAXReader saxReader = new SAXReader();
        Document document = saxReader.read(
            new File("路径" +
                "\\litestruts\\struts.xml"));

        return document;
    }

    private static String findClass(String actionName, Element root) {
        String classPath = null;
        for (Iterator i = root.elementIterator(); i.hasNext(); ) {
            Element action = (Element) i.next();
            if (actionName.equals(action.attribute("name").getText())) {
                classPath = action.attribute("class").getText();
                break;
            }
        }
        return classPath;
    }

    private static View handle(String classPath, Map<String, String> parameters
                , Element rootElement) {
        View view = new View();

        Class newClass = getClass(classPath);
        Object action = getObject(newClass);
        Element element = rootElement.element("action");


        if (action instanceof LoginAction) {
            LoginAction loginAction = (LoginAction) getAction(action, parameters);
            String answer = loginAction.execute();
            String page = getPage(element, answer);

            view.setJsp(page);
            view.setParameters(getMap(newClass, action));
        }

        return view;
    }

    private static Class getClass(String classPath) {
        try {
            return Class.forName(classPath);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }

    private static Object getObject(Class newClass) {
        try {
            return newClass.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return null;
    }

    private static Object getAction(Object action, Map<String, String> parameters) {
        LoginAction loginAction = (LoginAction) action;
        loginAction.setName(parameters.get("name"));
        loginAction.setPassword(parameters.get("password"));
        return loginAction;
    }

    private static String  getPage(Element element, String answer) {
        for (Iterator i = element.elementIterator(); i.hasNext(); ) {
            Element result = (Element) i.next();
            if (answer.equals(result.attribute("name").getText())) {
                return result.getText();
            }
        }
        return "";
    }

    private static Map<String, String> getMap(Class newClass, Object action) {
        Map<String, String> map = new HashMap<>();
        Method[] methods = newClass.getDeclaredMethods();
        String getterMethod;
        for (Method method : methods) {
            getterMethod = method.getName();
            if (Pattern.matches("get(\\w+)", getterMethod)) {
                try {
                    map.put(getterMethod.substring(3).toLowerCase(),
                        method.invoke(action).toString());
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                } catch (InvocationTargetException e) {
                    e.printStackTrace();
                }
            }

        }
        return map;
    }

}

//StrutsTest.java
package com.donaldy.litestruts;

import java.util.HashMap;
import java.util.Map;

import org.junit.Assert;
import org.junit.Test;

public class StrutsTest {

    @Test
    public void testLoginActionSuccess() {

        String actionName = "login";

        Map<String,String> params = new HashMap<String,String>();
        params.put("name","test");
        params.put("password","1234");


        View view  = Struts.runAction(actionName,params);        

        Assert.assertEquals("/jsp/homepage.jsp", view.getJsp());
        Assert.assertEquals("login successful", view.getParameters().get("message"));
    }

    @Test
    public void testLoginActionFailed() {
        String actionName = "login";
        Map<String,String> params = new HashMap<String,String>();
        params.put("name", "test");
        params.put("password", "123456"); //密码和预设的不一致

        View view  = Struts.runAction(actionName,params);        

        Assert.assertEquals("/jsp/showLogin.jsp", view.getJsp());
        Assert.assertEquals("login failed,please check your user/pwd", view.getParameters().get("message"));
    }
}

//View.java
package com.donaldy.litestruts;

import java.util.Map;

public class View {

    private String jsp;
    private Map parameters;

    public String getJsp() {
        return jsp;
    }
    public View setJsp(String jsp) {
        this.jsp = jsp;
        return this;
    }
    public Map getParameters() {
        return parameters;
    }
    public View setParameters(Map parameters) {
        this.parameters = parameters;
        return this;
    }
}

//struts.xml
<?xml version="1.0" encoding="UTF-8"?>
<struts>
    <action name="login" class="com.donaldy.litestruts.LoginAction">
        <result name="success">/jsp/homepage.jsp</result>
        <result name="fail">/jsp/showLogin.jsp</result>
    </action>
    <action name="logout" class="com.donaldy.litestruts.LogoutAction">
        <result name="success">/jsp/welcome.jsp</result>
        <result name="error">/jsp/error.jsp</result>
    </action>
</struts>

//LoginAction.java
package com.donaldy.litestruts;

public class LoginAction{
    private String name ;
    private String password;
    private String message;

    public LoginAction() {

    }

    public String getName() {
        return name;
    }

    public String getPassword() {
        return password;
    }

    public String execute(){
        if("test".equals(name) && "1234".equals(password)){
            this.message = "login successful";
            return "success";
        }
        this.message = "login failed,please check your user/pwd";
        return "fail";
    }

    public void setName(String name){
        this.name = name;
    }
    public void setPassword(String password){
        this.password = password;
    }
    public String getMessage(){
        return this.message;
    }
}