项目结构
image.png
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.ghgcn</groupId>
<artifactId>myspringmvc</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<dependencies>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.0.1</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<finalName>myspringmvc</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.2</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
</project>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<!-- 前端控制器 -->
<servlet>
<servlet-name>MyDispatcherServlet</servlet-name>
<servlet-class>com.ghgcn.myspringmvc.servlet.MyDispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<!--配置文件 -->
<param-value>classpath:application.properties</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>MyDispatcherServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<!--字符编码 -->
<filter>
<filter-name>UTF8Filter</filter-name>
<filter-class>com.ghgcn.myspringmvc.filter.UTF8Filter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>UTF8Filter</filter-name>
<url-pattern>/</url-pattern>
</filter-mapping>
</web-app>
properties
basePackage=com.ghgcn.myspringmvc
注解
/**
* 控制器
* @author Administrator
*
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MyController {
/**
* 表示给controller注册别名
* @return
*/
String value() default "";
}
/**
* 请求路径
* @author Administrator
*
*/
@Target(value={ElementType.METHOD,ElementType.TYPE})
@Documented
@Retention(RetentionPolicy.RUNTIME)
public @interface MyRequestMapping {
/**
* 表示访问该方法的url
* @return
*/
String value() default "";
}
/**
* 参数
* @author Administrator
*
*/
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MyRequestParam {
/**
* 表示参数的别名，必填
* @return
*/
String value();
}
helper
public class IOHelper {
public static void close(AutoCloseable closeable) {
try {
if (closeable != null) {
closeable.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
过滤器
package com.ghgcn.myspringmvc.filter;
import java.io.IOException;
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.http.HttpServletResponse;
public class UTF8Filter implements Filter {
private String encoding="UTF-8";
/**
* @see Filter#init(FilterConfig)
*/
public void init(FilterConfig fConfig) throws ServletException {
String initParameter = fConfig.getInitParameter("encoding");
if(initParameter!=null){
this.encoding=initParameter;
}
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
request.setCharacterEncoding(encoding);
chain.doFilter(request, response);
HttpServletResponse resp = (HttpServletResponse)response ;
resp.setCharacterEncoding(encoding);
}
@Override
public void destroy() {
}
}
MyDispatcherServlet 前端控制器
package com.ghgcn.myspringmvc.servlet;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.ghgcn.myspringmvc.annotation.MyController;
import com.ghgcn.myspringmvc.annotation.MyRequestMapping;
import com.ghgcn.myspringmvc.helper.IOHelper;
public class MyDispatcherServlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 7613183580743740653L;
/**
* 属性-加载配置文件
*/
private Properties properties = new Properties();
/**
* 所有类的名称
*/
private List<String> classNames = new ArrayList<>();
/**
* 注入的容器
*/
private Map<String, Object> ioc = new HashMap<>();
/**
* 请求地址映射-controller-方法
*/
private Map<String, Method> handlerMapping = new HashMap<>();
/**
* 控制器
*/
private Map<String, Object> controllerMap = new HashMap<>();
@Override
public void init(ServletConfig config) throws ServletException {
// 1.加载配置文件
doLoadConfig(config.getInitParameter("contextConfigLocation"));
// 2.初始化所有相关联的类,扫描用户设定的包下面所有的类 基础包下的所有类的全路径名称com.xx.xx.类名
doScanner(properties.getProperty("basePackage"));
// 3.拿到扫描到的类,通过反射机制,实例化,并且放到ioc容器中(k-v beanName-bean) beanName默认是首字母小写
doInstance();
// 4.初始化HandlerMapping(将url和method对应上)
initHandlerMapping();
}
/**
* 1.加载启 到的配置
*
* @param location
*/
private void doLoadConfig(String location) {
System.out.println("location "+location);
if(location.startsWith("classpath:")){
location=location.substring(location.indexOf(":")+1);
}
/**
* 加载文件 -application.properties
*/
InputStream inStream = this.getClass().getClassLoader().getResourceAsStream(location);
try {
this.properties.load(inStream);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (inStream != null) {
IOHelper.close(inStream);
}
}
}
/**
* 2.扫描包，基础包下的所有类的全路径名称com.xx.xx.类名
*
* @param property
*/
private void doScanner(String packageName) {
// 1.把所有的.替换成/
URL url = this.getClass().getClassLoader().getResource(packageName.replace(".", "/"));
System.out.println("url " + url.getFile());
/**
* 2.获取所有文件
*/
File file = new File(url.getFile());
for (File f : file.listFiles()) {
if (f.isDirectory()) {
// 递归
doScanner(packageName + "." + f.getName());
} else {
String className = packageName + "." + f.getName().replace(".class", "");
System.out.println("className " + className);
/**
* 反所有类都放在这个集合中-类的全路径
*/
classNames.add(className);
}
}
}
/**
* 3 拿到扫描到的类,通过反射机制,实例化,并且放到ioc容器中(k-v beanName-bean) beanName默认是首字母小写
*/
private void doInstance() {
if (classNames.isEmpty()) {
return;
}
for (String classname : classNames) {
try {
//反射来实例化(只有加@MyController需要实例化)
Class<?> clazz = Class.forName(classname);
if (clazz.isAnnotationPresent(MyController.class)) {
// 放入IOC容器 类首字母小写， 通过无参构造方法获取实例
ioc.put(toLowerFirstWord(clazz.getSimpleName()), clazz.newInstance());
} else {
continue;
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
continue;
} catch (InstantiationException e) {
e.printStackTrace();
continue;
} catch (IllegalAccessException e) {
e.printStackTrace();
continue;
}
}
}
/**
* 4.将请求的url与method中的方法对应
*/
private void initHandlerMapping() {
if (ioc.isEmpty()) {
return;
}
try {
for (Map.Entry<String, Object> entry : ioc.entrySet()) {
Class<? extends Object> clazz = entry.getValue().getClass();
/**
* 判断如果不是MyController 的注解，就下一个
*/
if (!clazz.isAnnotationPresent(MyController.class)) {
continue;
}
// 拼url时,是controller头的url拼上方法上的url
String baseUrl = "";
if (clazz.isAnnotationPresent(MyRequestMapping.class)) {
MyRequestMapping contollerAnnotation = clazz.getAnnotation(MyRequestMapping.class);
baseUrl = contollerAnnotation.value();
}
/**
* 获取所有方法的请求myrequestiongmapping
*/
Method[] methods = clazz.getMethods();
for (Method method : methods) {
if (!method.isAnnotationPresent(MyRequestMapping.class)) {
continue;
}
MyRequestMapping methodAnnotation = method.getAnnotation(MyRequestMapping.class);
/**
* 方法的请求路径
*/
String methodUrl = methodAnnotation.value();
/**
* 拼接
*/
String url = (baseUrl + "/" + methodUrl).replaceAll("/+", "/");
System.out.println("url " + url + " method " + method);
/**
* 将url与method做关联
*/
handlerMapping.put(url, method);
/**
* 控制器 -- 请求地址与控制器关系
*/
controllerMap.put(url, clazz.newInstance());
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
@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 {
// 处理请求
resp.setHeader("Content-type", "text/html;charset=UTF-8");
doDispatch(req, resp);
} catch (Exception e) {
resp.getWriter().write("500!! Server Exception");
}
}
/**
* 处理请求
*
* @param req
* @param resp
* @throws IOException
*/
private void doDispatch(HttpServletRequest req, HttpServletResponse resp) throws IOException {
if (handlerMapping.isEmpty()) {
return;
}
/**
* 获取请求路径
*/
String url = req.getRequestURI();
/**
* 上下路径
*/
String contextPath = req.getContextPath();
url = url.replace(contextPath, "").replaceAll("/+", "/");
/**
* 判断请求路径是否存在
*/
if (!handlerMapping.containsKey(url)) {
resp.getWriter().write("404 Not found");
return;
}
/**
* 获取请求的方法
*/
Method method = handlerMapping.get(url);
/**
* 获取方法的参数
*/
Class<?>[] parameterTypes = method.getParameterTypes();
/**
* 获取请求的方法的请求参数
*/
Map<String, String[]> requestparameterMap = req.getParameterMap();
/**
* 保存参数值
*/
Object[] paramValues = new Object[parameterTypes.length];
/**
* 方法的参数列表
*/
for (int i = 0; i < paramValues.length; i++) {
String requestParam = parameterTypes[i].getSimpleName();
System.out.println("requestParam "+requestParam);
/**
* 请求
*/
if (requestParam.equals("HttpServletRequest")) {
// 参数类型已明确，这边强转类型
paramValues[i] = req;
continue;
}
/**
* 响应
*/
if (requestParam.equals("HttpServletResponse")) {
paramValues[i] = resp;
continue;
}
/**
* 参数转换为
*/
if (requestParam.equals("String")) {
for (Entry<String, String[]> param : requestparameterMap.entrySet()) {
System.out.println("param "+param);
String value = Arrays.toString(param.getValue()).replaceAll("\\[|\\]", "").replaceAll(",\\s", ",");
System.out.println("value "+value);
paramValues[i] = value;
}
}
/**
* 通过反射来执行方法
* /第一个参数是method所对应的实例 在ioc容器中
*/
}
try {
method.invoke(controllerMap.get(url), paramValues);
} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
e.printStackTrace();
}
}
/**
* 把字符串的首字母小写
*
* @param name
* @return
*/
private String toLowerFirstWord(String name) {
char[] charArray = name.toCharArray();
charArray[0] += 32;
return String.valueOf(charArray);
}
}
测试
package com.ghgcn.myspringmvc.action;
import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.ghgcn.myspringmvc.annotation.MyController;
import com.ghgcn.myspringmvc.annotation.MyRequestMapping;
import com.ghgcn.myspringmvc.annotation.MyRequestParam;
@MyController
@MyRequestMapping("/test")
public class TestController {
@MyRequestMapping("/doTest")
public void test1(HttpServletRequest request, HttpServletResponse response, @MyRequestParam("param") String param) {
System.out.println("============test1=============");
System.out.println(param);
try {
//response.setHeader("Content-type", "text/html;charset=UTF-8");
response.getWriter().write("doTest method success! param:" + param);
} catch (IOException e) {
e.printStackTrace();
}
}
@MyRequestMapping("/doTest2")
public void test2(HttpServletRequest request, HttpServletResponse response,String test) {
System.out.println("==========test2=======");
System.out.println(test);
try {
//response.setHeader("Content-type", "text/html;charset=UTF-8");
response.getWriter().write("doTest2 method success!");
response.getWriter().write(test);
} catch (IOException e) {
e.printStackTrace();
}
}
}
image.png
image.png
