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

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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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发表至： java
2020-07-15
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