上回實現了一個簡易的Spring,那就順便實現一些SpringMVC吧。由於有了上回的基礎,這回實現比較快,晚飯前架構了一下,一晚上就寫得差不多了。自己實現的架構比較簡單,下面簡單介紹一下。
源碼下載:http://download.csdn.net/detail/jobsandczj/9844308
實現思路及工作流程:
定義一個DispatcherServlet,用來做請求入口。初始化時,去讀取配置文件,獲得Controller的包,然後“注入”Controller。SpringMVC它本身是有自己的IoC容器的,用來注入Controller以及它的組件,但IoC我在Spring裏玩過了,這回就沒有寫依賴注入。但完事後發現其實也沒省多少功夫,終歸還是要掃包,解析的。
得到Controller後就構建Handler。讓每個Handler與一個請求路徑對應,我只定義了兩種類型的Handler,一個是處理頁面轉發的,一個是返回Json數據的。每種Handler都有它的適配器,這就讓Controller的方法設置參數少了很多約束,只要是request,response,session這仨傢伙就行。
最後初始化適配器列表,以便在接收到請求後適配。
下面是Handler抽象類:
package MySpringMVC.springmvc;
import java.lang.reflect.Method;
/**
* Created by 10033 on 2017/5/16.
*/
public abstract class Handler {
protected Method method;
protected Object controller;
protected Class[] params;
protected RequestMethod requestMethod;
public Handler(Method method, Object controller, Class[] params, RequestMethod requestMethod) {
this.method = method;
this.controller = controller;
this.params = params;
this.requestMethod = requestMethod;
}
public Method getMethod() {
return method;
}
public void setMethod(Method method) {
this.method = method;
}
public Object getController() {
return controller;
}
public void setController(Object controller) {
this.controller = controller;
}
public Class[] getParams() {
return params;
}
public void setParams(Class[] params) {
this.params = params;
}
public RequestMethod getRequestMethod() {
return requestMethod;
}
public void setRequestMethod(RequestMethod requestMethod) {
this.requestMethod = requestMethod;
}
}
下面這個是操作工具類,進行方法參數適配和適配器列表初始化
package MySpringMVC.utils;
import MySpringMVC.springmvc.ClasspathPackageScanner;
import MySpringMVC.springmvc.HandlerAdapter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;
/**
* Created by 10033 on 2017/5/16.
*/
public class OperationUtil {
private static final Logger logger = LoggerFactory.getLogger(OperationUtil.class);
private static final String ADAPTER_PACKAGE="MySpringMVC.springmvc";
public static int makeObjectsByClasses
(Class[] classes, Object[] objects, HttpServletRequest request, HttpServletResponse response) throws Exception {
int cou=0;
for(Class cla:classes) {
if(cla==HttpServletRequest.class) {
objects[cou++]=request;
} else if(cla==HttpServletResponse.class) {
objects[cou++]=response;
} else if(cla==HttpSession.class) {
objects[cou++]=request.getSession();
} else {
throw new Exception("控制器參數錯誤");
}
}
return cou;
}
public static void initHandlerAdapterList(List<HandlerAdapter> list) {
try {
List<String> classStringList=new ClasspathPackageScanner(ADAPTER_PACKAGE).getFullyQualifiedClassNameList();
for(String s:classStringList) {
Class cla=Class.forName(s);
//實現了HandlerAdapter接口
if (HandlerAdapter.class.isAssignableFrom(cla)) {
Object obj=cla.newInstance();
list.add((HandlerAdapter) obj);
}
}
} catch (IOException e) {
logger.error(e.getMessage());
} catch (ClassNotFoundException e) {
logger.error(e.getMessage());
} catch (IllegalAccessException e) {
logger.error(e.getMessage());
} catch (InstantiationException e) {
logger.error(e.getMessage());
}
}
}
這是DispatcherServlet類,進行初始化和控制器調度,爲了管理靜態資源要進行servlet註冊。
package MySpringMVC.springmvc;
import MySpringMVC.utils.OperationUtil;
import MySpringMVC.utils.PropertiesReaderUtil;
import MySpringMVC.utils.StringUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* Created by 10033 on 2017/5/16.
*/
public class DispatcherServlet extends HttpServlet {
private static final Logger logger = LoggerFactory.getLogger(DispatcherServlet.class);
private String configName;
private Map<String, String> configMap;
private static final String SCAN_PACK="scan.package";
private static final String VIEWPATH_STATIC="viewpath.static";
private HandlerMap handleMap;
private List<HandlerAdapter> handlerAdapters = new ArrayList<HandlerAdapter>();
//初始化
public void init(String configName) throws ServletException {
super.init();
// configName=getInitParameter("contextConfigLocationName");
configMap= PropertiesReaderUtil.getProperties(configName);
String packages=configMap.get(SCAN_PACK);//獲得掃描包
DispatchHelper.setMap(configMap);
try {
List<String> list=new ClasspathPackageScanner(packages).getFullyQualifiedClassNameList();
handleMap=new HandlerMap(list);
} catch (IOException e) {
logger.error(e.getMessage());
}
OperationUtil.initHandlerAdapterList(handlerAdapters);
}
@Override
public void init(ServletConfig config) throws ServletException {
init(config.getInitParameter("contextConfigLocationName"));
ServletContext servletContext=config.getServletContext();
/*ServletRegistration servletRegistration = servletContext.getServletRegistration("jsp");
servletRegistration.addMapping("/WEB-INF/jsps*//*");*/
ServletRegistration servletRegistration2 = servletContext.getServletRegistration("default");
String[] staticString=configMap.get(VIEWPATH_STATIC).split(";");
for(int i=0;i<staticString.length;i++) {
servletRegistration2.addMapping(staticString[i].toLowerCase()+"/*");
}
}
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//獲取請求路徑
String requestUrl=StringUtil.getRequestURL(req);
Handler handler=handleMap.getHandler(requestUrl,req.getMethod());
if(null!=handler) {
for(HandlerAdapter handlerAdapter:handlerAdapters) {
if(handlerAdapter.support(handler)) {
handlerAdapter.setHandler(handler);
handlerAdapter.execute(req,resp);
break;
}
}
}else {
resp.sendError(HttpServletResponse.SC_NOT_FOUND);
}
}
}
這回還是有一些不足的,一是沒實現IoC,當然這是自己偷懶。但還有一個不足就是,由於前端只支持JSP,所以View,Model這些也都沒管。