接下来我们来完成MVC模块的功能,应该不需要再做说明。Spring MVC的入口就是从DispatcherServlet开始的,而前面的章节中已完成了web.xml的基础配置。下面就从DispatcherServlet开始添砖加瓦。
1 MVC顶层设计
1.1 GPDispatcherServlet
我们已经了解到Servlet的生命周期由init()到service()再到destory()组成,destory()方法我们不做实现。前面我们讲过,这是J2EE中模板模式的典型应用。下面先定义好全局变量:
- package com.tom.spring.formework.webmvc.servlet;
- import com.tom.spring.formework.annotation.GPController;
- import com.tom.spring.formework.annotation.GPRequestMapping;
- import com.tom.spring.formework.context.GPApplicationContext;
- import com.tom.spring.formework.webmvc.*;
- import lombok.extern.slf4j.Slf4j;
- import javax.servlet.ServletConfig;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import java.io.File;
- import java.io.IOException;
- import java.lang.reflect.Method;
- import java.util.*;
- import java.util.regex.Matcher;
- import java.util.regex.Pattern;
- //Servlet只是作为一个MVC的启动入口
- @Slf4j
- public class GPDispatcherServlet extends HttpServlet {
- private final String LOCATION = "contextConfigLocation";
- //读者可以思考一下这样设计的经典之处
- //GPHandlerMapping最核心的设计,也是最经典的
- //它直接干掉了Struts、Webwork等MVC框架
- private List<GPHandlerMapping> handlerMappings = new ArrayList<GPHandlerMapping>();
- private Map<GPHandlerMapping,GPHandlerAdapter> handlerAdapters = new HashMap<GPHandlerMapping, GPHandlerAdapter>();
- private List<GPViewResolver> viewResolvers = new ArrayList<GPViewResolver>();
- private GPApplicationContext context;
- }
- 下面实现init()方法,我们主要完成IoC容器的初始化和Spring MVC九大组件的初始化。
- @Override
- public void init(ServletConfig config) throws ServletException {
- //相当于把IoC容器初始化了
- context = new GPApplicationContext(config.getInitParameter(LOCATION));
- initStrategies(context);
- }
- protected void initStrategies(GPApplicationContext context) {
- //有九种策略
- //针对每个用户请求,都会经过一些处理策略处理,最终才能有结果输出
- //每种策略可以自定义干预,但是最终的结果都一致
- // ============= 这里说的就是传说中的九大组件 ================
- initMultipartResolver(context);//文件上传解析,如果请求类型是multipart,将通过MultipartResolver进行文件上传解析
- initLocaleResolver(context);//本地化解析
- initThemeResolver(context);//主题解析
- /** 我们自己会实现 */
- //GPHandlerMapping 用来保存Controller中配置的RequestMapping和Method的对应关系
- initHandlerMappings(context);//通过HandlerMapping将请求映射到处理器
- /** 我们自己会实现 */
- //HandlerAdapters 用来动态匹配Method参数,包括类转换、动态赋值
- initHandlerAdapters(context);//通过HandlerAdapter进行多类型的参数动态匹配
- initHandlerExceptionResolvers(context);//如果执行过程中遇到异常,将交给HandlerExceptionResolver来解析
- initRequestToViewNameTranslator(context);//直接将请求解析到视图名
- /** 我们自己会实现 */
- //通过ViewResolvers实现动态模板的解析
- //自己解析一套模板语言
- initViewResolvers(context);//通过viewResolver将逻辑视图解析到具体视图实现
- initFlashMapManager(context);//Flash映射管理器
- }
- private void initFlashMapManager(GPApplicationContext context) {}
- private void initRequestToViewNameTranslator(GPApplicationContext context) {}
- private void initHandlerExceptionResolvers(GPApplicationContext context) {}
- private void initThemeResolver(GPApplicationContext context) {}
- private void initLocaleResolver(GPApplicationContext context) {}
- private void initMultipartResolver(GPApplicationContext context) {}
- //将Controller中配置的RequestMapping和Method进行一一对应
- private void initHandlerMappings(GPApplicationContext context) {
- //按照我们通常的理解应该是一个Map
- //Map<String,Method> map;
- //map.put(url,Method)
- //首先从容器中获取所有的实例
- String [] beanNames = context.getBeanDefinitionNames();
- try {
- for (String beanName : beanNames) {
- //到了MVC层,对外提供的方法只有一个getBean()方法
- //返回的对象不是BeanWrapper,怎么办?
- Object controller = context.getBean(beanName);
- //Object controller = GPAopUtils.getTargetObject(proxy);
- Class<?> clazz = controller.getClass();
- if (!clazz.isAnnotationPresent(GPController.class)) {
- continue;
- }
- String baseUrl = "";
- if (clazz.isAnnotationPresent(GPRequestMapping.class)) {
- GPRequestMapping requestMapping = clazz.getAnnotation(GPRequestMapping.class);
- baseUrl = requestMapping.value();
- }
- //扫描所有的public类型的方法
- Method[] methods = clazz.getMethods();
- for (Method method : methods) {
- if (!method.isAnnotationPresent(GPRequestMapping.class)) {
- continue;
- }
- GPRequestMapping requestMapping = method.getAnnotation(GPRequestMapping.class);
- String regex = ("/" + baseUrl + requestMapping.value().replaceAll("\\*", ".*")).replaceAll("/+", "/");
- Pattern pattern = Pattern.compile(regex);
- this.handlerMappings.add(new GPHandlerMapping(pattern, controller, method));
- log.info("Mapping: " + regex + " , " + method);
- }
- }
- }catch (Exception e){
- e.printStackTrace();
- }
- }
- private void initHandlerAdapters(GPApplicationContext context) {
- //在初始化阶段,我们能做的就是,将这些参数的名字或者类型按一定的顺序保存下来
- //因为后面用反射调用的时候,传的形参是一个数组
- //可以通过记录这些参数的位置index,逐个从数组中取值,这样就和参数的顺序无关了
- for (GPHandlerMapping handlerMapping : this.handlerMappings){
- //每个方法有一个参数列表,这里保存的是形参列表
- this.handlerAdapters.put(handlerMapping,new GPHandlerAdapter());
- }
- }
- private void initViewResolvers(GPApplicationContext context) {
- //在页面中输入http://localhost/first.html
- //解决页面名字和模板文件关联的问题
- String templateRoot = context.getConfig().getProperty("templateRoot");
- String templateRootPath = this.getClass().getClassLoader().getResource (templateRoot).getFile();
- File templateRootDir = new File(templateRootPath);
- for (File template : templateRootDir.listFiles()) {
- this.viewResolvers.add(new GPViewResolver(templateRoot));
- }
- }
在上面的代码中,我们只实现了九大组件中的三大核心组件的基本功能,分别是HandlerMapping、HandlerAdapter、ViewResolver,完成MVC最核心的调度功能。其中HandlerMapping就是策略模式的应用,用输入URL间接调用不同的Method已达到获取结果的目的。顾名思义,HandlerAdapter应用的是适配器模式,将Request的字符型参数自动适配为Method的Java实参,主要实现参数列表自动适配和类型转换功能。ViewResolver也算一种策略,根据不同的请求选择不同的模板引擎来进行页面的渲染。接下来看service()方法,它主要负责接收请求,得到Request和Response对象。在Servlet子类中service()方法被拆分成doGet()方法和doPost()方法。我们在doGet()方法中直接调用doPost()方法,在doPost()方法中调用doDispatch()方法,真正的调用逻辑由doDispatch()来执行。
- @Override
- protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- this.doPost(req,resp);
- }
- @Override
- protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- try {
- doDispatch(req, resp);
- }catch (Exception e){
- resp.getWriter().write("<font size='25' color='blue'>500 Exception</font><br/>Details: <br/>" + Arrays.toString(e.getStackTrace()).replaceAll("\\[|\\]","")
- .replaceAll("\\s","\r\n") + "<font color='green'><i>Copyright@GupaoEDU </i></font>");
- e.printStackTrace();
- }
- }
- private void doDispatch(HttpServletRequest req, HttpServletResponse resp) throws Exception{
- //根据用户请求的URL来获得一个Handler
- GPHandlerMapping handler = getHandler(req);
- if(handler == null){
- processDispatchResult(req,resp,new GPModelAndView("404"));
- return;
- }
- GPHandlerAdapter ha = getHandlerAdapter(handler);
- //这一步只是调用方法,得到返回值
- GPModelAndView mv = ha.handle(req, resp, handler);
- //这一步才是真的输出
- processDispatchResult(req,resp, mv);
- }
- private void processDispatchResult(HttpServletRequest request,HttpServletResponse response, GPModelAndView mv) throws Exception {
- //调用viewResolver的resolveViewName()方法
- if(null == mv){ return;}
- if(this.viewResolvers.isEmpty()){ return;}
- if (this.viewResolvers != null) {
- for (GPViewResolver viewResolver : this.viewResolvers) {
- GPView view = viewResolver.resolveViewName(mv.getViewName(), null);
- if (view != null) {
- view.render(mv.getModel(),request,response);
- return;
- }
- }
- }
- }
- private GPHandlerAdapter getHandlerAdapter(GPHandlerMapping handler) {
- if(this.handlerAdapters.isEmpty()){return null;}
- GPHandlerAdapter ha = this.handlerAdapters.get(handler);
- if (ha.supports(handler)) {
- return ha;
- }
- return null;
- }
- private GPHandlerMapping getHandler(HttpServletRequest req) {
- if(this.handlerMappings.isEmpty()){ return null;}
- String url = req.getRequestURI();
- String contextPath = req.getContextPath();
- url = url.replace(contextPath,"").replaceAll("/+","/");
- for (GPHandlerMapping handler : this.handlerMappings) {
- Matcher matcher = handler.getPattern().matcher(url);
- if(!matcher.matches()){ continue;}
- return handler;
- }
- return null;
- }
GPDisptcherServlet的完整代码请关注微信公众号回复“Spring”。下面补充实现上面的代码中缺失的依赖类。
1.2 GPHandlerMapping
我们已经知道HandlerMapping主要用来保存URL和Method的对应关系,这里其实使用的是策略模式。
- package com.tom.spring.formework.webmvc;
- import java.lang.reflect.Method;
- import java.util.regex.Pattern;
- public class GPHandlerMapping {
- private Object controller; //目标方法所在的contrller对象
- private Method method; //URL对应的目标方法
- private Pattern pattern; //URL的封装
- public GPHandlerMapping(Pattern pattern,Object controller, Method method) {
- this.controller = controller;
- this.method = method;
- this.pattern = pattern;
- }
- public Object getController() {
- return controller;
- }
- public void setController(Object controller) {
- this.controller = controller;
- }
- public Method getMethod() {
- return method;
- }
- public void setMethod(Method method) {
- this.method = method;
- }
- public Pattern getPattern() {
- return pattern;
- }
- public void setPattern(Pattern pattern) {
- this.pattern = pattern;
- }
- }
1.3 GPHandlerAdapter
原生Spring的HandlerAdapter主要完成请求传递到服务端的参数列表与Method实参列表的对应关系,完成参数值的类型转换工作。核心方法是handle(),在handle()方法中用反射来调用被适配的目标方法,并将转换包装好的参数列表传递过去。
- package com.tom.spring.formework.webmvc;
- import com.tom.spring.formework.annotation.GPRequestParam;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import java.lang.annotation.Annotation;
- import java.util.Arrays;
- import java.util.HashMap;
- import java.util.Map;
- //专人干专事
- public class GPHandlerAdapter {
- public boolean supports(Object handler){
- return (handler instanceof GPHandlerMapping);
- }
- public GPModelAndView handle(HttpServletRequest req, HttpServletResponse resp, Object handler) throws Exception{
- GPHandlerMapping handlerMapping = (GPHandlerMapping)handler;
- //每个方法有一个参数列表,这里保存的是形参列表
- Map<String,Integer> paramMapping = new HashMap<String, Integer>();
- //这里只是给出命名参数
- Annotation[][] pa = handlerMapping.getMethod().getParameterAnnotations();
- for (int i = 0; i < pa.length ; i ++) {
- for (Annotation a : pa[i]) {
- if(a instanceof GPRequestParam){
- String paramName = ((GPRequestParam) a).value();
- if(!"".equals(paramName.trim())){
- paramMapping.put(paramName,i);
- }
- }
- }
- }
- //根据用户请求的参数信息,跟Method中的参数信息进行动态匹配
- //resp 传进来的目的只有一个:将其赋值给方法参数,仅此而已
- //只有当用户传过来的ModelAndView为空的时候,才会新建一个默认的
- //1. 要准备好这个方法的形参列表
- //方法重载时形参的决定因素:参数的个数、参数的类型、参数顺序、方法的名字
- //只处理Request和Response
- Class<?>[] paramTypes = handlerMapping.getMethod().getParameterTypes();
- for (int i = 0;i < paramTypes.length; i ++) {
- Class<?> type = paramTypes[i];
- if(type == HttpServletRequest.class ||
- type == HttpServletResponse.class){
- paramMapping.put(type.getName(),i);
- }
- }
- //2. 得到自定义命名参数所在的位置
- //用户通过URL传过来的参数列表
- Map<String,String[]> reqParameterMap = req.getParameterMap();
- //3. 构造实参列表
- Object [] paramValues = new Object[paramTypes.length];
- for (Map.Entry<String,String[]> param : reqParameterMap.entrySet()) {
- String value = Arrays.toString(param.getValue()).replaceAll("\\[|\\]",""). replaceAll("\\s","");
- if(!paramMapping.containsKey(param.getKey())){continue;}
- int index = paramMapping.get(param.getKey());
- //因为页面传过来的值都是String类型的,而在方法中定义的类型是千变万化的
- //所以要针对我们传过来的参数进行类型转换
- paramValues[index] = caseStringValue(value,paramTypes[index]);
- }
- if(paramMapping.containsKey(HttpServletRequest.class.getName())) {
- int reqIndex = paramMapping.get(HttpServletRequest.class.getName());
- paramValues[reqIndex] = req;
- }
- if(paramMapping.containsKey(HttpServletResponse.class.getName())) {
- int respIndex = paramMapping.get(HttpServletResponse.class.getName());
- paramValues[respIndex] = resp;
- }
- //4. 从handler中取出Controller、Method,然后利用反射机制进行调用
- Object result = handlerMapping.getMethod().invoke(handlerMapping.getController(), paramValues);
- if(result == null){ return null; }
- boolean isModelAndView = handlerMapping.getMethod().getReturnType() == GPModelAndView.class;
- if(isModelAndView){
- return (GPModelAndView)result;
- }else{
- return null;
- }
- }
- private Object caseStringValue(String value,Class<?> clazz){
- if(clazz == String.class){
- return value;
- }else if(clazz == Integer.class){
- return Integer.valueOf(value);
- }else if(clazz == int.class){
- return Integer.valueOf(value).intValue();
- }else {
- return null;
- }
- }
- }
1.4 GPModelAndView
原生Spring中ModelAndView类主要用于封装页面模板和要往页面传送的参数的对应关系。
- package com.tom.spring.formework.webmvc;
- import java.util.Map;
- public class GPModelAndView {
- private String viewName; //页面模板的名称
- private Map<String,?> model; //往页面传送的参数
- public GPModelAndView(String viewName) {
- this(viewName,null);
- }
- public GPModelAndView(String viewName, Map<String, ?> model) {
- this.viewName = viewName;
- this.model = model;
- }
- public String getViewName() {
- return viewName;
- }
- public void setViewName(String viewName) {
- this.viewName = viewName;
- }
- public Map<String, ?> getModel() {
- return model;
- }
- public void setModel(Map<String, ?> model) {
- this.model = model;
- }
- }
1.5 GPViewResolver
原生Spring中的ViewResolver主要完成模板名称和模板解析引擎的匹配。通过在Serlvet中调用resolveViewName()方法来获得模板所对应的View。在这个Mini版本中简化了实现,只实现了一套默认的模板引擎,语法也是完全自定义的。
- package com.tom.spring.formework.webmvc;
- import java.io.File;
- import java.util.Locale;
- //设计这个类的主要目的是:
- //1. 将一个静态文件变为一个动态文件
- //2. 根据用户传送不同的参数,产生不同的结果
- //最终输出字符串,交给Response输出
- public class GPViewResolver {
- private final String DEFAULT_TEMPLATE_SUFFIX = ".html";
- private File templateRootDir;
- private String viewName;
- public GPViewResolver(String templateRoot){
- String templateRootPath = this.getClass().getClassLoader().getResource(templateRoot). getFile();
- this.templateRootDir = new File(templateRootPath);
- }
- public GPView resolveViewName(String viewName, Locale locale) throws Exception {
- this.viewName = viewName;
- if(null == viewName || "".equals(viewName.trim())){ return null;}
- viewName = viewName.endsWith(DEFAULT_TEMPLATE_SUFFIX) ? viewName : (viewName + DEFAULT_TEMPLATE_SUFFIX);
- File templateFile = new File((templateRootDir.getPath() + "/" + viewName).replaceAll ("/+", "/"));
- return new GPView(templateFile);
- }
- public String getViewName() {
- return viewName;
- }
- }
1.6 GPView
这里的GPView就是前面所说的自定义模板解析引擎,其核心方法是render()。在render()方法中完成对模板的渲染,最终返回浏览器能识别的字符串,通过Response输出。
- package com.tom.spring.formework.webmvc;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import java.io.RandomAccessFile;
- import java.util.Map;
- import java.io.File;
- import java.util.regex.Matcher;
- import java.util.regex.Pattern;
- public class GPView {
- public static final String DEFAULT_CONTENT_TYPE = "text/html;charset=utf-8";
- private File viewFile;
- public GPView(File viewFile){
- this.viewFile = viewFile;
- }
- public String getContentType(){
- return DEFAULT_CONTENT_TYPE;
- }
- public void render(Map<String, ?> model,HttpServletRequest request, HttpServletResponse response) throws Exception{
- StringBuffer sb = new StringBuffer();
- RandomAccessFile ra = new RandomAccessFile(this.viewFile,"r");
- try {
- String line = null;
- while (null != (line = ra.readLine())) {
- line = new String(line.getBytes("ISO-8859-1"),"utf-8");
- Pattern pattern = Pattern.compile("¥\\{[^\\}]+\\}",Pattern.CASE_INSENSITIVE);
- Matcher matcher = pattern.matcher(line);
- while (matcher.find()) {
- String paramName = matcher.group();
- paramName = paramName.replaceAll("¥\\{|\\}","");
- Object paramValue = model.get(paramName);
- if (null == paramValue) { continue; }
- //要把¥{}中间的这个字符串取出来
- line = matcher.replaceFirst(makeStringForRegExp(paramValue.toString()));
- matcher = pattern.matcher(line);
- }
- sb.append(line);
- }
- }finally {
- ra.close();
- }
- response.setCharacterEncoding("utf-8");
- //response.setContentType(DEFAULT_CONTENT_TYPE);
- response.getWriter().write(sb.toString());
- }
- //处理特殊字符
- public static String makeStringForRegExp(String str) {
- return str.replace("\\", "\\\\").replace("*", "\\*")
- .replace("+", "\\+").replace("|", "\\|")
- .replace("{", "\\{").replace("}", "\\}")
- .replace("(", "\\(").replace(")", "\\)")
- .replace("^", "\\^").replace("$", "\\$")
- .replace("[", "\\[").replace("]", "\\]")
- .replace("?", "\\?").replace(",", "\\,")
- .replace(".", "\\.").replace("&", "\\&");
- }
- }
从上面的代码可以看出,GPView是基于HTML文件来对页面进行渲染的。但是加入了一些自定义语法,例如在模板页面中扫描到¥{name}这样的表达式,就会从ModelAndView的Model中找到name所对应的值,并且用正则表达式将其替换(外国人喜欢用美元符号$,我们的模板引擎就用人民币符号¥)。
2 业务代码实现
2.1 IQueryService
定义一个负责查询业务的顶层接口IQueryService,提供一个query()方法:
- package com.tom.spring.demo.service;
- /**
- * 查询业务
- *
- */
- public interface IQueryService {
- /**
- * 查询
- */
- public String query(String name);
- }
2.2 QueryService
查询业务的实现QueryService也非常简单,就是打印一下调用时间和传入的参数,并封装为JSON格式返回:
- package com.tom.spring.demo.service.impl;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import com.tom.spring.demo.service.IQueryService;
- import com.tom.spring.formework.annotation.GPService;
- import lombok.extern.slf4j.Slf4j;
- /**
- * 查询业务
- *
- */
- @GPService
- @Slf4j
- public class QueryService implements IQueryService {
- /**
- * 查询
- */
- public String query(String name) {
- SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- String time = sdf.format(new Date());
- String json = "{name:\"" + name + "\",time:\"" + time + "\"}";
- log.info("这是在业务方法中打印的:" + json);
- return json;
- }
- }
2.3 IModifyService
定义一个增、删、改业务的顶层接口IModifyService:
- package com.tom.spring.demo.service;
- /**
- * 增、删、改业务
- */
- public interface IModifyService {
- /**
- * 增加
- */
- public String add(String name, String addr) ;
- /**
- * 修改
- */
- public String edit(Integer id, String name);
- /**
- * 删除
- */
- public String remove(Integer id);
- }
2.4 ModifyService
增、删、改业务的实现ModifyService也非常简单,主要是打印传过来的参数:
- package com.tom.spring.demo.service.impl;
- import com.tom.spring.demo.service.IModifyService;
- import com.tom.spring.formework.annotation.GPService;
- /**
- * 增、删、改业务
- */
- @GPService
- public class ModifyService implements IModifyService {
- /**
- * 增加
- */
- public String add(String name,String addr) {
- return "modifyService add,name=" + name + ",addr=" + addr;
- }
- /**
- * 修改
- */
- public String edit(Integer id,String name) {
- return "modifyService edit,id=" + id + ",name=" + name;
- }
- /**
- * 删除
- */
- public String remove(Integer id) {
- return "modifyService id=" + id;
- }
- }
2.5 MyAction
Controller的主要功能是负责调度,不做业务实现。业务实现方法全部在Service层,一般我们会将Service实例注入Controller。MyAction中主要实现对IQueryService和IModifyService的调度,统一返回结果:
- package com.tom.spring.demo.action;
- import java.io.IOException;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import com.tom.spring.demo.service.IModifyService;
- import com.tom.spring.demo.service.IQueryService;
- import com.tom.spring.formework.annotation.GPAutowired;
- import com.tom.spring.formework.annotation.GPController;
- import com.tom.spring.formework.annotation.GPRequestMapping;
- import com.tom.spring.formework.annotation.GPRequestParam;
- import com.tom.spring.formework.webmvc.GPModelAndView;
- /**
- * 公布接口URL
- */
- @GPController
- @GPRequestMapping("/web")
- public class MyAction {
- @GPAutowired IQueryService queryService;
- @GPAutowired IModifyService modifyService;
- @GPRequestMapping("/query.json")
- public GPModelAndView query(HttpServletRequest request, HttpServletResponse response,
- @GPRequestParam("name") String name){
- String result = queryService.query(name);
- return out(response,result);
- }
- @GPRequestMapping("/add*.json")
- public GPModelAndView add(HttpServletRequest request,HttpServletResponse response,
- @GPRequestParam("name") String name,@GPRequestParam("addr") String addr){
- String result = modifyService.add(name,addr);
- return out(response,result);
- }
- @GPRequestMapping("/remove.json")
- public GPModelAndView remove(HttpServletRequest request,HttpServletResponse response,
- @GPRequestParam("id") Integer id){
- String result = modifyService.remove(id);
- return out(response,result);
- }
- @GPRequestMapping("/edit.json")
- public GPModelAndView edit(HttpServletRequest request,HttpServletResponse response,
- @GPRequestParam("id") Integer id,
- @GPRequestParam("name") String name){
- String result = modifyService.edit(id,name);
- return out(response,result);
- }
- private GPModelAndView out(HttpServletResponse resp,String str){
- try {
- resp.getWriter().write(str);
- } catch (IOException e) {
- e.printStackTrace();
- }
- return null;
- }
- }
2.6 PageAction
专门设计PageAction是为了演示Mini版Spring对模板引擎的支持,实现从Controller层到View层的传参,以及对模板的渲染进行最终输出:
- package com.tom.spring.demo.action;
- import java.util.HashMap;
- import java.util.Map;
- import com.tom.spring.demo.service.IQueryService;
- import com.tom.spring.formework.annotation.GPAutowired;
- import com.tom.spring.formework.annotation.GPController;
- import com.tom.spring.formework.annotation.GPRequestMapping;
- import com.tom.spring.formework.annotation.GPRequestParam;
- import com.tom.spring.formework.webmvc.GPModelAndView;
- /**
- * 公布接口URL
- */
- @GPController
- @GPRequestMapping("/")
- public class PageAction {
- @GPAutowired IQueryService queryService;
- @GPRequestMapping("/first.html")
- public GPModelAndView query(@GPRequestParam("teacher") String teacher){
- String result = queryService.query(teacher);
- Map<String,Object> model = new HashMap<String,Object>();
- model.put("teacher", teacher);
- model.put("data", result);
- model.put("token", "123456");
- return new GPModelAndView("first.html",model);
- }
- }
3 定制模板页面
为了更全面地演示页面渲染效果,分别定义了first.html对应PageAction中的first.html请求、404.html默认页和500.html异常默认页。
3.1 first.html
first.html定义如下:
- <!DOCTYPE html>
- <html lang="zh-cn">
- <head>
- <meta charset="utf-8">
- <title>SpringMVC模板引擎演示</title>
- </head>
- <center>
- <h1>大家好,我是¥{teacher}老师<br/>欢迎大家一起来探索Spring的世界</h1>
- <h3>Hello,My name is ¥{teacher}</h3>
- <div>¥{data}</div>
- Token值:¥{token}
- </center>
- </html>
3.2 404.html
404.html定义如下:
- <!DOCTYPE html>
- <html lang="zh-cn">
- <head>
- <meta charset="utf-8">
- <title>页面去火星了</title>
- </head>
- <body>
- <font size='25' color='red'>404 Not Found</font><br/><font color='green'><i>Copyright @GupaoEDU</i></font>
- </body>
- </html>
3.3 500.html
500.html定义如下:
- <!DOCTYPE html>
- <html lang="zh-cn">
- <head>
- <meta charset="utf-8">
- <title>服务器好像累了</title>
- </head>
- <body>
- <font size='25' color='blue'>500 服务器好像有点累了,需要休息一下</font><br/>
- <b>Message:¥{detail}</b><br/>
- <b>StackTrace:¥{stackTrace}</b><br/>
- <font color='green'><i>Copyright@GupaoEDU</i></font>
- </body>
- </html>
4 运行效果演示
在浏览器中输入 http://localhost/web/query.json?name=Tom ,就会映射到MyAction中的@GPRequestMapping(“query.json”)对应的query()方法,得到如下图所示结果。
在浏览器中输入 http://localhost/web/addTom.json?name=tom&addr=HunanChangsha ,就会映射到MyAction中的@GPRequestMapping(“add*.json”)对应的add()方法,得到如下图所示结果。
在浏览器中输入 http://localhost/web/remove.json?id=66 ,就会映射到MyAction中的@GPRequestMapping(“remove.json”)对应的remove()方法,并将id自动转换为int类型,得到如下图所示结果。
在浏览器中输入 http://localhost/web/edit.json?id=666&name=Tom ,就会映射到MyAction中的@GPRequestMapping(“edit.json”)对应的edit()方法,并将id自动转换为int类型,得到如下图所示结果。
在浏览器中输入 http://localhost/first.html?teacher=Tom ,就会映射到PageAction中的@GPRequestMapping(“first.html”)对应的query()方法,得到如下图所示结果。
到这里,已经实现了Spring从IoC、ID到MVC的完整功能。虽然忽略了一些细节,但是我们已经了解到,Spring的核心设计思想其实并没有我们想象得那么神秘。我们已经巧妙地用到了工厂模式、静态代理模式、适配器模式、模板模式、策略模式、委派模式等,使得代码变得非常优雅。