Servlet3.0实现的简单mvc框架

jar包准备：servlet-api-3.0.jar
项目结构如下：

注解Mapping ，用于映射url地址

/*
* 文件名：Action.java
* 版权：Copyright 2007-2016 517na Tech. Co. Ltd. All Rights Reserved.
* 描述： Action.java
* 修改人：peiyu
* 修改时间：2016年7月29日
* 修改内容：新增
*/
package com.servlet3.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface Mapping {
String value();
}

ActionModel，用于封装Action信息

/*
* 文件名：ActionModel.java
* 版权：Copyright 2007-2016 517na Tech. Co. Ltd. All Rights Reserved.
* 描述： ActionModel.java
* 修改人：peiyu
* 修改时间：2016年8月1日
* 修改内容：新增
*/
package com.servlet3.util;
import java.io.Serializable;
import java.lang.reflect.Method;
/**
* @author
peiyu
*/
public class ActionModel implements Serializable{
/**
* 添加字段注释.
*/
private static final long serialVersionUID = 1L;
private String className;
private Method method;
private Object action;
/**
* 设置className.
* @return 返回className
*/
public String getClassName() {
return className;
}
/**
* 获取className.
* @param className 要设置的className
*/
public void setClassName(String className) {
this.className = className;
}
/**
* 设置method.
* @return 返回method
*/
public Method getMethod() {
return method;
}
/**
* 获取method.
* @param method 要设置的method
*/
public void setMethod(Method method) {
this.method = method;
}
/**
* 设置action.
* @return 返回action
*/
public Object getAction() {
return action;
}
/**
* 获取action.
* @param action 要设置的action
*/
public void setAction(Object action) {
this.action = action;
}
}

MyFilter过滤器，初始化时创建扫描指定包下的所有类的注解，解析URL，创建Bean

/*
* 文件名：MyFilter.java
* 版权：Copyright 2007-2016 517na Tech. Co. Ltd. All Rights Reserved.
* 描述： MyFilter.java
* 修改人：peiyu
* 修改时间：2016年7月29日
* 修改内容：新增
*/
package com.servlet3.filter;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.net.URLDecoder;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import com.servlet3.annotation.Mapping;
import com.servlet3.exception.URLException;
import com.servlet3.util.ActionModel;
import com.servlet3.util.CommentedProperties;
/**
*
* @author peiyu
*/
@WebFilter(filterName = "MyFilter", urlPatterns = {"/*"})
public class MyFilter implements Filter {
@Override
public void destroy() {
System.out.println("-----------------------destroy-----------------------");
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest httpServletRequest = (HttpServletRequest) request;
String uri = httpServletRequest.getRequestURI();
//访问的逻辑地址/myServlet3
String url = uri.substring(uri.indexOf("/", 1));
httpServletRequest.getRequestURL();
System.out.println("-----------------------doFilter-----------------------");
request.setAttribute("url", url);
request.getRequestDispatcher("/myServlet3").forward(request,response);
}
/**
*1. 获取配置文件中配置的需扫描的包名
*2. 根据包名扫描注解，获取URL，创建Bean实例
*/
@Override
public void init(FilterConfig config) throws ServletException {
//获取配置文件中的包路径
CommentedProperties properties = new CommentedProperties();
//
/D:/software/apache-tomcat-7.0.59/webapps/Servlet3.0/WEB-INF/classes/scan-package.properties
String classPath = MyFilter.class.getClassLoader().getResource("").getPath();
String path = classPath + "scan-package.properties";
System.out.println("####1加载配置文件:" + path);
try {
path = URLDecoder.decode(path, "UTF-8");
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
}
System.out.println("####2加载配置文件:" + path);
try {
properties.load(new FileInputStream(path), "UTF-8");
} catch (IOException e) {
e.printStackTrace();
}
//获取到包路径
String scanPackage = properties.getProperty("scan-package").replace(".", "/");
/*************************** 扫描包下的所有文件 ***************************************/
//获取到class文件路径
path = classPath + scanPackage;
Map<String, ActionModel> urls = new HashMap<>();
File file = new File(path);
//获取Action，url信息
getFileUrls(file, urls);
//将Action，url信息放到ServletContext
config.getServletContext().setAttribute("urls", urls);
}
/**
* 获取URL.
*/
private void getFileUrls(File file, Map<String, ActionModel> urls) {
if (file.isDirectory()) { //如果是文件夹，获取文件夹下的文件
File[] files = file.listFiles();
for (File temp : files) {
if (temp.isDirectory()) {
getFileUrls(temp, urls);
} else {
getFileUrl(temp, urls);
}
}
} else { //如果是文件
getFileUrl(file, urls);
}
}
/**
* 获取URL,创建Action bean.
*/
@SuppressWarnings("rawtypes")
private void getFileUrl(File temp, Map<String, ActionModel> urls) {
String path;
path = temp.getPath();
String className = path.substring(path.indexOf("com"), path.lastIndexOf(".")).replace("\", ".");
try {
Class clazz = Class.forName(className);
//获取类注解
String startUrl = "";
//Annotation[] annotations = clazz.getAnnotations();
//for (Annotation annotation : annotations) {
//
if (annotation instanceof Mapping) { //判断是mapping
//
startUrl = ((Mapping) annotation).value();
//
}
//}
if (clazz.isAnnotationPresent(Mapping.class)) {
startUrl = ((Mapping)clazz.getAnnotation(Mapping.class)).value();
}
//获取方法上注解
Method[] methods = clazz.getMethods();
Object action=clazz.newInstance();
for (Method method : methods) {
if (method.isAnnotationPresent(Mapping.class)) {
ActionModel actionModel = new ActionModel();
actionModel.setClassName(className);
actionModel.setMethod(method);
actionModel.setAction(action);
Mapping annotation=method.getAnnotation(Mapping.class);
String key = startUrl + ((Mapping) annotation).value();
if (urls.containsKey(key)) {
throw new URLException("已存在URL：" + key);
} else {
urls.put(key, actionModel);
}
}
//annotations = method.getAnnotations();
//for (Annotation annotation : annotations) {
//
if (annotation instanceof Mapping) { //判断是mapping
//
ActionModel actionModel=new ActionModel();
//
actionModel.setClassName(className);
//
actionModel.setMethod(method);
//
actionModel.setAction(action);
//
String key = startUrl + ((Mapping) annotation).value();
//
if (urls.containsKey(key)) {
//
throw new URLException("已存在URL："+key);
//
}else {
//
urls.put(key, actionModel);
//
}
//
}
//}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

scan-package.properties配置需要扫描的包

scan-package=com.servlet3.controller

默认访问的Servlet，通过该Servlet找到指定的URL地址

/*
* 文件名：MyServlet3.java
* 版权：Copyright 2007-2016 517na Tech. Co. Ltd. All Rights Reserved.
* 描述： MyServlet3.java
* 修改人：peiyu
* 修改时间：2016年7月29日
* 修改内容：新增
*/
package com.servlet3.controller;
import java.io.IOException;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.servlet3.util.ActionModel;
/**
* name：当前Servlet 的名称
* urlPatterns：请求的url
* loadOnStartup：tomcat启动时就初始化该servlet
* initParams：初始化参数
* name：参数名
* value：参数值
*
* @author peiyu
*/
@WebServlet(name = "MyServlet3",
urlPatterns = {"/myServlet3"},
loadOnStartup = 1,
initParams = {@WebInitParam(name = "name", value = "java"),
@WebInitParam(name = "age", value = "1")})
public class MyServlet3 extends HttpServlet {
/**
* 添加字段注释.
*/
private static final long serialVersionUID = 1L;
@SuppressWarnings({"unchecked"})
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String url=(String) req.getAttribute("url");
Map<String, ActionModel> urls =(Map<String, ActionModel>) req.getServletContext().getAttribute("urls");
ActionModel actionModel=urls.get(url);
if (actionModel!=null) {
try {
Object res=actionModel.getMethod().invoke(actionModel.getAction(), req,resp);
//根据返回的结果类型，返回值进行处理
if (res instanceof String) {
if (((String) res).startsWith("redirect:")) {
//......
}else if (((String) res).startsWith("forward:")) {
//......
}
}else{
//......
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}

测试的UserAction

/*
* 文件名：UserAction.java
* 版权：Copyright 2007-2016 517na Tech. Co. Ltd. All Rights Reserved.
* 描述： UserAction.java
* 修改人：peiyu
* 修改时间：2016年7月29日
* 修改内容：新增
*/
package com.servlet3.controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.servlet3.annotation.Mapping;
/**
* @author
peiyu
*/
@Mapping(value="/myServlet3")
public class UserAction {
@Mapping(value="/login")
public String login(HttpServletRequest req, HttpServletResponse resp){
System.out.println("--------login-------------");
return "redirect:register";
}
//register
@Mapping(value="/register")
public String register(HttpServletRequest req, HttpServletResponse resp){
System.out.println("--------register-------------");
return "redirect:login";
}
}

最后，启动服务器，访问http://localhost:8072/Servlet3.0/myServlet3/login?name=java&age=1就会找到UserAction的login方法。

最后

以上就是爱笑小笼包为你收集整理的Servlet3.0实现的简单mvc框架的全部内容，希望文章能够帮你解决Servlet3.0实现的简单mvc框架所遇到的程序开发问题。

如果觉得靠谱客网站的内容还不错，欢迎将靠谱客网站推荐给程序员好友。