1. DispatcherServlet
package com.csdn.mymvc.core; import com.csdn.fruit.dto.Result; import com.csdn.fruit.util.RequestUtil; import com.csdn.fruit.util.ResponseUtil; import com.csdn.mymvc.annotation.RequestBody; import jakarta.servlet.RequestDispatcher; import jakarta.servlet.ServletContext; import jakarta.servlet.ServletException; import jakarta.servlet.annotation.WebServlet; import jakarta.servlet.http.HttpServlet; import jakarta.servlet.http.HttpServletRequest; import jakarta.servlet.http.HttpServletResponse; import org.junit.Test; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Parameter; import java.util.Arrays; import java.util.Map; @WebServlet("/*") public class DispatcherServlet extends HttpServlet { private final String BEAN_FACTORY = "beanFactory"; private final String CONTROLLER_BEAN_MAP = "controllerBeanMap"; @Test public void uri() { String uri = "/fruit/index"; String[] arr = uri.split("/"); System.out.println(Arrays.toString(arr));//[, fruit, index] } @Override protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String[] staticResourceSuffixes = {".html", ".jsp", ".jpg", ".png", ".gif", ".css", " .js", ".ico"}; String uri = req.getRequestURI(); if (Arrays.stream(staticResourceSuffixes).anyMatch(uri::endsWith)) { RequestDispatcher defaultDispatcher = req.getServletContext().getNamedDispatcher("default"); defaultDispatcher.forward(req, resp); } else { String[] arr = uri.split("/"); if (arr == null || arr.length != 3) { throw new RuntimeException(uri + "Illegal!"); } //[, fruit, index] String requestMapping = "/" + arr[1]; String methodMapping = "/" + arr[2]; ServletContext application = getServletContext(); ControllerDefinition controllerDefinition = ((Map<String, ControllerDefinition>) application.getAttribute(CONTROLLER_BEAN_MAP)) .get(requestMapping); if (controllerDefinition == null) { throw new RuntimeException(requestMapping + "The corresponding controller component does not exist!"); } //Get the request method, such as get or post String requestMethodStr = req.getMethod().toLowerCase(); //get_/index Method method = controllerDefinition.getMethodMappingMap().get(requestMethodStr + "_" + methodMapping); Object controllerBean = controllerDefinition.getControllerBean(); try { //Step 1: Parameter processing //Get the parameters on the method method Parameter[] parameters = method.getParameters(); Object[] parameterValues = new Object[parameters.length]; for (int i = 0; i < parameters.length; i + + ) { Parameter parameter = parameters[i]; RequestBody requestBodyAnnotation = parameter.getDeclaredAnnotation(RequestBody.class); Object parameterValue = null; if (requestBodyAnnotation != null) { parameterValue = RequestUtil.readObject(req, parameter.getType()); } else { //Get parameter name //Before JDK8, the parameter object (Parameter object) was obtained through reflection //Then the name of the formal parameter cannot be obtained through the parameter.getName() method. What is returned is arg0, arg1, arg2.... //Starting from JDK8, the Class obtained by reflection technology can contain the names of method parameters, but an additional setting is required: //Add a parameter to the java compiler: -parameters String paramName = parameter.getName(); String paramValueStr = req.getParameter(paramName); if (paramValueStr != null) { //Get the type of parameter String parameterTypeName = parameter.getType().getName(); parameterValue = switch (parameterTypeName) { case "java.lang.String"-> paramValueStr; case "java.lang.Integer"-> Integer.parseInt(paramValueStr); default -> null; }; } } parameterValues[i] = parameterValue; } //Step 2: Method call //Call the method method in the controllerBean object method.setAccessible(true); Object returnObj = method.invoke(controllerBean, parameterValues); if (returnObj != null & amp; & amp; returnObj instanceof Result) { Result result= (Result) returnObj; ResponseUtil.print(resp,result); } } catch (IllegalAccessException e) { e.printStackTrace(); throw new RuntimeException(e); } catch (InvocationTargetException e) { e.printStackTrace(); throw new RuntimeException(e); } } } }2. FruitController
package com.csdn.fruit.controller; import com.csdn.fruit.dto.PageInfo; import com.csdn.fruit.dto.PageQueryParam; import com.csdn.fruit.dto.Result; import com.csdn.fruit.pojo.Fruit; import com.csdn.fruit.service.FruitService; import com.csdn.mymvc.annotation.*; @Controller @RequestMapping("/fruit") public class FruitController { @Autowire private FruitService fruitService; @GetMapping("/index") public Result index(Integer pageNo,String keyword) { if (pageNo == null) { pageNo = 1; } if (keyword == null) { keyword = ""; } PageQueryParam pageQueryParam = new PageQueryParam(pageNo, 5, keyword); PageInfo<Fruit> pageInfo = fruitService.getFruitPageInfo(pageQueryParam); return Result.OK(pageInfo); } @PostMapping("/add") public Result add(@RequestBody Fruit fruit) { fruitService.addFruit(fruit); return Result.OK(); } @GetMapping("/del") public Result del(Integer fid){ fruitService.delFruit(fid); return Result.OK(); } @GetMapping("/edit") public Result edit(Integer fid){ Fruit fruit = fruitService.getFruitById(fid); return Result.OK(fruit); } @GetMapping("/getFname") public Result getFname(String fname){ //fname is the request parameter Fruit fruit = fruitService.getFruitByFname(fname); return fruit == null ? Result.OK() : Result.Fail(); } @PostMapping("/update") public Result update(@RequestBody Fruit fruit){ //fruit is the request body parameter fruitService.updateFruit(fruit); return Result.OK(); } }
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