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从零写一个具有IOCAOPMVC功能的框架学习笔记11-MVC功能之http请求处理器的编写简易框架最后一公里

jiezi

1. 本章须要实现的内容：

  1. 实现 ControllerRequestProcessor 类的编写：Controller 申请处理器
  2. 实现 JspRequestProcessor 类的编写：jsp 资源申请解决
  3. 实现 PreRequestProcessor 类的编写：申请预处理, 包含编码以及门路解决
  4. 实现 StaticResourceRequestProcessor 类的编写：动态资源申请解决，包含但不限于图片，css，以及 js 文件等, 转发到 DefaultServlet

2. PreRequestProcessor 类的编写

2.1 PreRequestProcessor 类须要实现的代码 


package org.myframework.mvc.processor.impl;

/**
 * @author wuyiccc
 * @date 2020/6/16 18:54
 * 岂曰无衣，与子同袍~
 */

import lombok.extern.slf4j.Slf4j;
import org.myframework.mvc.RequestProcessorChain;
import org.myframework.mvc.processor.RequestProcessor;

/**
 * 申请预处理, 包含编码以及门路解决
 */
@Slf4j
public class PreRequestProcessor implements RequestProcessor {

    @Override
    public boolean process(RequestProcessorChain requestProcessorChain) throws Exception {

        // 1. 设置申请编码，将其对立设置成 UTF-8
        requestProcessorChain.getRequest().setCharacterEncoding("UTF-8");
        // 2. 将申请门路开端的 / 剔除，为后续匹配 Controller 申请门路做筹备
        //（个别 Controller 的解决门路是 /aaa/bbb，所以如果传入的门路结尾是 /aaa/bbb/，// 就须要解决成 /aaa/bbb）String requestPath = requestProcessorChain.getRequestPath();
        //http://localhost:8080/myframework requestPath="/"
        if (requestPath.length() > 1 && requestPath.endsWith("/")) {requestProcessorChain.setRequestPath(requestPath.substring(0, requestPath.length() - 1));
        }
        log.info("preprocess request {} {}", requestProcessorChain.getRequestMethod(), requestProcessorChain.getRequestPath());

        return true;
    }
}

2.2 PreRequestProcessor 类相干代码解说：

3. StaticResourceRequestProcessor 类的编写

3.1 StaticResourceRequestProcessor 类须要实现的代码:

package com.wuyiccc.helloframework.mvc.processor.impl;

import com.wuyiccc.helloframework.mvc.RequestProcessorChain;
import com.wuyiccc.helloframework.mvc.processor.RequestProcessor;
import lombok.extern.slf4j.Slf4j;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;

/**
 * @author wuyiccc
 * @date 2020/7/14 22:40
 * 岂曰无衣，与子同袍~
 */
@Slf4j
public class StaticResourceRequestProcessor implements RequestProcessor {


    public static final String DEFAULT_TOMCAT_SERVLET = "default";
    public static final String STATIC_RESOURCE_PREFIX = "/static/";

    //tomcat 默认申请派发器 RequestDispatcher 的名称
    RequestDispatcher defaultDispatcher;

    public StaticResourceRequestProcessor(ServletContext servletContext) {this.defaultDispatcher = servletContext.getNamedDispatcher(DEFAULT_TOMCAT_SERVLET);
        if (this.defaultDispatcher == null) {throw new RuntimeException("There is no default tomcat servlet");
        }
        log.info("The default servlet for static resource is {}", DEFAULT_TOMCAT_SERVLET);
    }

    @Override
    public boolean process(RequestProcessorChain requestProcessorChain) throws Exception {

        //1. 通过申请门路判断是否是申请的动态资源 webapp/static
        if (isStaticResource(requestProcessorChain.getRequestPath())) {
            //2. 如果是动态资源，则将申请转发给 default servlet 解决
            defaultDispatcher.forward(requestProcessorChain.getRequest(), requestProcessorChain.getResponse());
            return false;
        }
        return true;
    }

    // 通过申请门路前缀（目录）是否为动态资源 /static/
    private boolean isStaticResource(String path) {return path.startsWith(STATIC_RESOURCE_PREFIX);
    }

}

3.2 StaticResourceRequestProcessor 类相干代码解说：

4. JspRequestProcessor

4.1 JspRequestProcessor 须要实现的代码：

package org.myframework.mvc.processor.impl;

import org.myframework.mvc.RequestProcessorChain;
import org.myframework.mvc.processor.RequestProcessor;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;

/**
 * @author wuyiccc
 * @date 2020/6/16 18:59
 * 岂曰无衣，与子同袍~
 */

/**
 * jsp 资源申请解决
 */
public class JspRequestProcessor implements RequestProcessor {


    //jsp 申请的 RequestDispatcher 的名称
    private static final String JSP_SERVLET = "jsp";
    //Jsp 申请资源门路前缀
    private static final String JSP_RESOURCE_PREFIX = "/templates/";

    /**
     * jsp 的 RequestDispatcher, 解决 jsp 资源
     */
    private RequestDispatcher jspServlet;

    public JspRequestProcessor(ServletContext servletContext) {jspServlet = servletContext.getNamedDispatcher(JSP_SERVLET);
        if (null == jspServlet) {throw new RuntimeException("there is no jsp servlet");
        }
    }

    @Override
    public boolean process(RequestProcessorChain requestProcessorChain) throws Exception {if (isJspResource(requestProcessorChain.getRequestPath())) {jspServlet.forward(requestProcessorChain.getRequest(), requestProcessorChain.getResponse());
            return false;
        }
        return true;
    }

    /**
     * 是否申请的是 jsp 资源
     */
    private boolean isJspResource(String url) {return url.startsWith(JSP_RESOURCE_PREFIX);
    }
}

4.2 JspRequestProcessor 相干代码解说：

5. ControllerRequestProcessor 类的编写

5.1 ControllerRequestProcessor 须要实现的代码:

package org.myframework.mvc.processor.impl;

import lombok.extern.slf4j.Slf4j;
import org.myframework.core.BeanContainer;
import org.myframework.mvc.RequestProcessorChain;
import org.myframework.mvc.annotation.RequestMapping;
import org.myframework.mvc.annotation.RequestParam;
import org.myframework.mvc.annotation.ResponseBody;
import org.myframework.mvc.processor.RequestProcessor;
import org.myframework.mvc.render.JsonResultRender;
import org.myframework.mvc.render.ResourceNotFoundResultRender;
import org.myframework.mvc.render.ResultRender;
import org.myframework.mvc.render.ViewResultRender;
import org.myframework.mvc.type.ControllerMethod;
import org.myframework.mvc.type.RequestPathInfo;
import org.myframework.util.ConverterUtil;
import org.myframework.util.ValidationUtil;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Parameter;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author wuyiccc
 * @date 2020/6/16 19:14
 * 岂曰无衣，与子同袍~
 */

/**
 * Controller 申请处理器
 */
@Slf4j
public class ControllerRequestProcessor implements RequestProcessor {

    //IOC 容器
    private BeanContainer beanContainer;

    // 申请和 controller 办法的映射汇合
    private Map<RequestPathInfo, ControllerMethod> pathControllerMethodMap = new ConcurrentHashMap<>();


    /**
     * 依附容器的能力，建设起申请门路、申请办法与 Controller 办法实例的映射
     */
    public ControllerRequestProcessor() {this.beanContainer = BeanContainer.getInstance();
        Set<Class<?>> requestMappingSet = beanContainer.getClassesByAnnotation(RequestMapping.class);
        initPathControllerMethodMap(requestMappingSet);
    }

    private void initPathControllerMethodMap(Set<Class<?>> requestMappingSet) {if (ValidationUtil.isEmpty(requestMappingSet)) {return;}

        //1. 遍历所有被 @RequestMapping 标记的类，获取类下面该注解的属性值作为一级门路
        for (Class<?> requestMappingClass : requestMappingSet) {RequestMapping requestMapping = requestMappingClass.getAnnotation(RequestMapping.class);
            String basePath = requestMapping.value();
            if (!basePath.startsWith("/")) {basePath = "/" + basePath;}

            //2. 遍历类里所有被 @RequestMapping 标记的办法，获取办法下面该注解的属性值，作为二级门路
            Method[] methods = requestMappingClass.getDeclaredMethods();
            if (ValidationUtil.isEmpty(methods)) {continue;}

            for (Method method : methods) {if (method.isAnnotationPresent(RequestMapping.class)) {RequestMapping methodRequest = method.getAnnotation(RequestMapping.class);
                    String methodPath = methodRequest.value();

                    if (!methodPath.startsWith("/")) {methodPath = "/" + basePath;}


                    String url = basePath + methodPath;

                    //3. 解析办法里被 @RequestParam 标记的参数，// 获取该注解的属性值，作为参数名，// 获取被标记的参数的数据类型，建设参数名和参数类型的映射
                    Map<String, Class<?>> methodParams = new HashMap<>();

                    Parameter[] parameters = method.getParameters();

                    if (!ValidationUtil.isEmpty(parameters)) {for (Parameter parameter : parameters) {RequestParam param = parameter.getAnnotation(RequestParam.class);

                            // 目前暂定为 Controller 办法外面所有的参数都须要 @RequestParam 注解
                            if (param == null) {throw new RuntimeException("The parameter must have @RequestParam");
                            }

                            methodParams.put(param.value(), parameter.getType());
                        }
                    }

                    //4. 将获取到的信息封装成 RequestPathInfo 实例和 ControllerMethod 实例，搁置到映射表里
                    String httpMethod = String.valueOf(methodRequest.method());

                    RequestPathInfo requestPathInfo = new RequestPathInfo(httpMethod, url);

                    if (this.pathControllerMethodMap.containsKey(requestPathInfo)) {log.warn("duplicate url:{} registration，current class {} method{} will override the former one",
                                requestPathInfo.getHttpPath(), requestMappingClass.getName(), method.getName());
                    }

                    ControllerMethod controllerMethod = new ControllerMethod(requestMappingClass, method, methodParams);

                    this.pathControllerMethodMap.put(requestPathInfo, controllerMethod);
                }
            }
        }

    }

    @Override
    public boolean process(RequestProcessorChain requestProcessorChain) throws Exception {

        //1. 解析 HttpServletRequest 的申请办法, 申请门路，获取对应的 ControllerMethod 实例
        String method = requestProcessorChain.getRequestMethod();
        String path = requestProcessorChain.getRequestPath();

        ControllerMethod controllerMethod = this.pathControllerMethodMap.get(new RequestPathInfo(method, path));

        if (controllerMethod == null) {requestProcessorChain.setResultRender(new ResourceNotFoundResultRender(method, path));
            return false;
        }

        //2. 解析申请参数，并传递给获取到的 ControllerMethod 实例去执行
        Object result = invokeControllerMethod(controllerMethod, requestProcessorChain.getRequest());

        //3. 依据解决的后果，抉择对应的 render 进行渲染
        setResultRender(result, controllerMethod, requestProcessorChain);

        return true;
    }


    /**
     * 依据不同状况设置不同的渲染器
     */
    private void setResultRender(Object result, ControllerMethod controllerMethod, RequestProcessorChain requestProcessorChain) {if (result == null) {return;}

        ResultRender resultRender;

        boolean isJson = controllerMethod.getInvokeMethod().isAnnotationPresent(ResponseBody.class);
        if (isJson) {resultRender = new JsonResultRender(result);
        } else {resultRender = new ViewResultRender(result);
        }

        requestProcessorChain.setResultRender(resultRender);
    }

    private Object invokeControllerMethod(ControllerMethod controllerMethod, HttpServletRequest request) {

        //1. 从申请里获取 GET 或者 POST 的参数名及其对应的值
        Map<String, String> requestParamMap = new HashMap<>();

        //GET，POST 办法的申请参数获取形式
        Map<String, String[]> parameterMap = request.getParameterMap();

        for (Map.Entry<String, String[]> parameter : parameterMap.entrySet()) {if (!ValidationUtil.isEmpty(parameter.getValue())) {
                // 只反对一个参数对应一个值的模式
                requestParamMap.put(parameter.getKey(), parameter.getValue()[0]);
            }

        }

        //2. 依据获取到的申请参数名及其对应的值，以及 controllerMethod 外面的参数和类型的映射关系，去实例化出办法对应的参数
        List<Object> methodParams = new ArrayList<>();

        Map<String, Class<?>> methodParamMap = controllerMethod.getMethodParameters();


        for (String paramName : methodParamMap.keySet()) {Class<?> type = methodParamMap.get(paramName);
            String requestValue = requestParamMap.get(paramName);
            Object value;

            // 只反对 String 以及根底类型 char,int,short,byte,double,long,float,boolean, 及它们的包装类型
            if (requestValue == null) {
                // 将申请里的参数值转成适配于参数类型的空值
                value = ConverterUtil.primitiveNull(type);
            } else {value = ConverterUtil.convert(type, requestValue);
            }
            methodParams.add(value);

        }

        //3. 执行 Controller 外面对应的办法并返回后果
        Object controller = beanContainer.getBean(controllerMethod.getControllerClass());
        Method invokeMethod = controllerMethod.getInvokeMethod();
        invokeMethod.setAccessible(true);
        Object result;

        try {if (methodParams.size() == 0) {result = invokeMethod.invoke(controller);
            } else {result = invokeMethod.invoke(controller, methodParams.toArray());
            }

        } catch (InvocationTargetException e) {// 如果是调用异样的话，须要通过 e.getTargetException()
            // 去获取执行办法抛出的异样
            throw new RuntimeException(e.getTargetException());
        } catch (IllegalAccessException e) {throw new RuntimeException(e);
        }

        return result;
    }
}

5.2 ControllerRequestProcessor 相干代码解说


6. ConverterUtil 值转换工具类的补充


相干代码如下:

package com.wuyiccc.helloframework.util;

/**
 * @author wuyiccc
 * @date 2020/7/15 8:02
 * 岂曰无衣，与子同袍~
 */
public class ConverterUtil {

    /**
     * 返回根本数据类型的空值
     * 须要非凡解决的根本类型即 int\double\short\long\byte\float\boolean
     *
     * @param type 参数类型
     * @return 对应的空值
     */
    public static Object primitiveNull(Class<?> type) {if (type == int.class || type == double.class || type == short.class || type == long.class || type == byte.class || type == float.class) {return 0;} else if (type == boolean.class) {return false;}
        return null;
    }


    /**
     * String 类型转换成对应的参数类型
     *
     * @param type         参数类型
     * @param requestValue 值
     * @return 转换后的 Object
     */
    public static Object convert(Class<?> type, String requestValue) {if (isPrimitive(type)) {if (ValidationUtil.isEmpty(requestValue)) {return primitiveNull(type);
            }

            if (type.equals(int.class) || type.equals(Integer.class)) {return Integer.parseInt(requestValue);
            } else if (type.equals(String.class)) {return requestValue;} else if (type.equals(Double.class) || type.equals(double.class)) {return Double.parseDouble(requestValue);
            } else if (type.equals(Float.class) || type.equals(float.class)) {return Float.parseFloat(requestValue);
            } else if (type.equals(Long.class) || type.equals(long.class)) {return Long.parseLong(requestValue);
            } else if (type.equals(Boolean.class) || type.equals(boolean.class)) {return Boolean.parseBoolean(requestValue);
            } else if (type.equals(Short.class) || type.equals(short.class)) {return Short.parseShort(requestValue);
            } else if (type.equals(Byte.class) || type.equals(byte.class)) {return Byte.parseByte(requestValue);
            }

            return requestValue;
        } else {throw new RuntimeException("count not support non primitive type conversion yet");
        }

    }


    /**
     * 断定是否根本数据类型 (包含包装类以及 String)
     *
     * @param type 参数类型
     * @return 是否为根本数据类型
     */
    private static boolean isPrimitive(Class<?> type) {
        return type == boolean.class
                || type == Boolean.class
                || type == double.class
                || type == Double.class
                || type == float.class
                || type == Float.class
                || type == short.class
                || type == Short.class
                || type == int.class
                || type == Integer.class
                || type == long.class
                || type == Long.class
                || type == String.class
                || type == byte.class
                || type == Byte.class
                || type == char.class
                || type == Character.class;
    }
}

github 地址：https://github.com/wuyiccc/he…

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