手写springmvc 框架1.0版

Spring MVC属于SpringFrameWork的后续产品，已经融合在Spring Web Flow里面。Spring 框架提供了构建 Web 应用程序的全功能 MVC 模块。使用 Spring 可插入的 MVC 架构，从而在使用Spring进行WEB开发时，可以选择使用Spring的Spring MVC框架或集成其他MVC开发框架，如Struts1(现在一般不用)，Struts 2(一般老项目使用)等。

springmvc工作流程图

搭建项目

pom 依赖

项目启动配置jetty插件

自定义注解

核心类 GpDispatcherServlet

package com.gupao.servlet.mvcframework;

import com.gupao.servlet.mvcframework.annotation.*;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

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.io.InputStream;

import java.lang.annotation.Annotation;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.net.URL;

import java.util.*;

public class GpDispatcherServlet extends HttpServlet {

private static final Loggerlogger = LoggerFactory.getLogger(GpDispatcherServlet.class);

//保存配置文件扫描到的内容

private Properties contextConfig = new Properties();

//保存扫描到的类

private List classNameList = new ArrayList();

//ioc容器

private Map ioc = new HashMap();

//保存url对应的mapping

// private Map handMapping = new HashMap();

// 为啥不用map handmapping 本身的功能url methond对应单一职责原则

private List<handMapping> = new ArrayList();

@Override

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

doPost(req, resp);

}

@Override

protected void doPost(HttpServletRequest req, HttpServletResponse resp)throws IOException {

//调用运行阶段

try {

doDispatch(req, resp);

} catch (Exception e) {

e.printStackTrace();

resp.getWriter().write("500 exception " + Arrays.toString(e.getStackTrace()));

}

private void doDispatch(HttpServletRequest req, HttpServletResponse response)throws Exception{

HandMapping handMapping = getHandler(req);

if (handMapping ==null) {

response.getWriter().write("404 Not Found");

return;

}

//获得形参列表

Class [] paramTypes = handMapping.getParamTyps();

Object [] paramValues = new Object[paramTypes.length];

Map stringMap = req.getParameterMap();

for (Map.Entry param : stringMap.entrySet()) {

String value = Arrays.toString(param.getValue()).replaceAll("\\[|\\]", "")

.replaceAll("\\s", ",");

if (!handMapping.paramIndexMapping.containsKey(param.getKey())) {continue;}

int index = handMapping.paramIndexMapping.get(param.getKey());

paramValues[index] = convert(paramTypes[index], value);

}

//请求参数是否有httpservletRequest httpservletResponse

if (handMapping.paramIndexMapping.containsKey(HttpServletRequest.class.getName())) {

int reqIndex = handMapping.paramIndexMapping.get(HttpServletRequest.class.getName());

paramValues[reqIndex] = req;

}

if (handMapping.paramIndexMapping.containsKey(HttpServletResponse.class.getName())) {

int respIndex = handMapping.paramIndexMapping.get(HttpServletResponse.class.getName());

paramValues[respIndex] = response;

}

Object object = handMapping.method.invoke(handMapping.controller, paramValues);

if (object ==null) {return;}

response.getWriter().write(object.toString());

}

private HandMapping getHandler (HttpServletRequest req) {

if (handMapping.isEmpty()) {return null;}

String url = req.getRequestURI().replaceAll("/gupaospring", "");//绝对路径这里暂时写死

//处理成相对路径

String contextPath = req.getContextPath();

logger.info("contextPath : [{}]", contextPath);

url = url.replaceAll(contextPath, "").replaceAll("/+", "/");

for (HandMapping handMapping : this.handMapping) {

if (handMapping.getUrl().equals(url)) {

return handMapping;

}

return null;

}

//http基于string传输

private Object convert(Class type, String value) {

if (Integer.class == type) {

return Integer.valueOf(value);

} else if (Double.class == type) {

return Double.valueOf(value);

}

return value;

}

//配置阶段初始化阶段

@Override

public void init(ServletConfig config)throws ServletException {

//加载配置文件模板模式

logger.info("access init method.......");

doLoadConfig(config.getInitParameter("contextConfigLocation"));

//扫描相关类

doScanner(contextConfig.getProperty("scanPackage"));

//初始化相关类放到Ioc容器中

doInstance();

//完成依赖注入

doAutowired();

//初始化handmapping

initHandMapping();

logger.info("gp srpingframework complete");

}

private void initHandMapping() {

if (ioc.isEmpty()) {return;}

for (Map.Entry entry :ioc.entrySet()) {

Class clazz = entry.getValue().getClass();

if (!clazz.isAnnotationPresent(GpController.class)) {continue;}

String baseUrl ="";

if (clazz.isAnnotationPresent(GpRequestMapping.class)) {

GpRequestMapping requestMapping = clazz.getAnnotation(GpRequestMapping.class);

baseUrl = requestMapping.value().trim();//类上的url;

}

//默认获取所有的public方法

for (Method method : clazz.getMethods()) {

if (!method.isAnnotationPresent(GpRequestMapping.class)) {continue;}

GpRequestMapping requestMapping = method.getAnnotation(GpRequestMapping.class);

String url = (baseUrl +"/" + requestMapping.value().trim()).replaceAll("/+", "/");

// handMapping.put(url, method);

this.handMapping.add(new HandMapping(url, method, entry.getValue()));

System.out.println("url:" + url +"method:" + method +"controller:" + entry.getValue());

}

//自动注入

private void doAutowired() {

if (ioc.isEmpty()) {return;}

for (Map.Entry entry :ioc.entrySet()) {

//declared 所有的特定的字段包括private protected 等字段

Field [] fields = entry.getValue().getClass().getDeclaredFields();

for (Field field : fields) {

if (!field.isAnnotationPresent(GpAutowried.class)) {continue;}

GpAutowried autowried = field.getAnnotation(GpAutowried.class);

String beanName = autowried.value().trim();

if ("".equals(beanName)) {

//接口类型作为key 到ioc容器中取值

beanName = field.getType().getName();

}

//如果是public 意外的修饰符强制赋值

field.setAccessible(true);

//反射动态给字段赋值

try {

field.set(entry.getValue(), ioc.get(beanName));

} catch (IllegalAccessException e) {

e.printStackTrace();

}

//注入到ioc容器中去

private void doInstance() {

if (classNameList.isEmpty()) {return;}

try {

for (String className :classNameList) {

Class clazz = Class.forName(className);

if (clazz.isAnnotationPresent(GpController.class)) {

Object instance = clazz.newInstance();

String beanName = toLowerFirstCase(clazz.getSimpleName());

ioc.put(beanName, instance);

} else if (clazz.isAnnotationPresent(GpService.class)) {

GpService service = clazz.getAnnotation(GpService.class);

//beanName 为空

String beanName = service.value();

Object instance = clazz.newInstance();

if ("".equals(service.value())) {

beanName = toLowerFirstCase(clazz.getSimpleName());

}

ioc.put(beanName, instance);

//接口名称

for (Class i : clazz.getInterfaces()) {

if (ioc.containsKey(i.getName())) {

throw new Exception("the" + i.getName() +"is exits");

}

ioc.put(i.getName(), instance);

}

} else {

continue;

}

} catch (Exception e) {

e.printStackTrace();

}

private String toLowerFirstCase(String simpleName) {

char [] chars = simpleName.toCharArray();

//加32是因为大小写字母的ascii相差32 大写字母的asci小于小写字母的ascII

chars[0] +=32;

return String.valueOf(chars);

}

private void doScanner(String scanPackage) {

//scanPackage=com.gupao.servlet包路径变成文件路径

//classpath

URL url = this.getClass().getClassLoader().getResource("/" + scanPackage.replaceAll("\\.", "/"));

File classpath =new File(url.getFile());

for (File file : classpath.listFiles()) {

if (file.isDirectory()) {

doScanner(scanPackage +"." + file.getName());

} else {

if (!file.getName().endsWith(".class")){continue;}

String className = (scanPackage +"." + file.getName().replace(".class", ""));

classNameList.add(className);

}

private void doLoadConfig(String contextConfigLocation) {

//直接从类路径下 spring主配置文件的路径读取放到properties中

//保存到内存中scanPackage=com.gupao.servlet

logger.info("acccess doLoadConfig method .......");

InputStream inputStream =null;

inputStream = this.getClass().getClassLoader().getResourceAsStream(contextConfigLocation);

try {

contextConfig.load(inputStream);

} catch (IOException e) {

e.printStackTrace();

} finally {

if (inputStream !=null) {

try {

inputStream.close();

} catch (IOException e) {

e.printStackTrace();

}

//保存一个url和method对应关系handMapping策略模式

//解决多个参数问题不然参数容易错位

public class HandMapping {

private String url;

private Method method;

private Object controller;

private Class [] paramTyps;

//形参列表

private Mapparam IndexMapping;

public StringgetUrl() {

return url;

}

public void setUrl(String url) {

this.url = url;

}

public MethodgetMethod() {

return method;

}

public void setMethod(Method method) {

this.method = method;

}

public ObjectgetController() {

return controller;

}

public void setController(Object controller) {

this.controller = controller;

}

public Class[]getParamTyps() {

return paramTyps;

}

public void setParamTyps(Class[] paramTyps) {

this.paramTyps = paramTyps;

}

public HandMapping(String url, Method method, Object controller) {

this.url = url;

this.method = method;

this.controller = controller;

paramTyps = method.getParameterTypes();

paramIndexMapping =new HashMap();

putParamIndexMapping(method);

}

private void putParamIndexMapping(Method method) {

Annotation[][] pa = method.getParameterAnnotations();

for (int i =0; i < pa.length; i++) {

for (Annotation a : pa[i]) {

if (ainstanceof GpRequestParam) {//拿到参数注解的值

String paramName = ((GpRequestParam) a).value();

if (!"".equals(paramName.trim())) {//一个key对应一个数组二维数组

paramIndexMapping.put(paramName, i);

}

Class[] paramType = method.getParameterTypes();

for (int i =0; i < paramType.length; i++) {

Class type = paramType[i];

if (type == HttpServletRequest.class || type == HttpServletResponse.class) {

paramIndexMapping.put(type.getName(), i);

}

看DemoAction方法

package com.gupao.servlet.action;

import com.gupao.servlet.mvcframework.annotation.GpAutowried;

import com.gupao.servlet.mvcframework.annotation.GpController;

import com.gupao.servlet.mvcframework.annotation.GpRequestMapping;

import com.gupao.servlet.mvcframework.annotation.GpRequestParam;

import com.gupao.servlet.service.IDemoService;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@GpController

@GpRequestMapping(value ="/demo")

public class DemoAction {

private static final Loggerlogger = LoggerFactory.getLogger(DemoAction.class);

@GpAutowried

private IDemoServicedemoService;

@GpRequestMapping(value ="/query")

public void query(HttpServletRequest request, HttpServletResponse response,

@GpRequestParam("name") String name) {

logger.info("access query query");

try {

response.getWriter().write(name);

} catch (IOException e) {

e.printStackTrace();

}

@GpRequestMapping(value ="/add")

public void add(HttpServletRequest request, HttpServletResponse response,

@GpRequestParam("a") Integer a,

@GpRequestParam("b") Integer b) {

logger.info("access add add");

try {

response.getWriter().write("a + b = " + (a + b));

} catch (IOException e) {

e.printStackTrace();

}

@GpRequestMapping(value ="/sub")

public void sub(HttpServletRequest request, HttpServletResponse response,

@GpRequestParam("a") Double a,

@GpRequestParam("b") Double b) {

logger.info("access add sub");

try {

response.getWriter().write("a - b = " + (a - b));

} catch (IOException e) {

e.printStackTrace();

}

@GpRequestMapping(value ="/remove")

public String remove(@GpRequestParam("id") Integer id) {

logger.info("access add remove");

return "id = " + id;

}

测试：query 方法存在当前参数

不存在当前参数报异常

add 方法

sub方法

remove方法