一个简单的servlet容器实现（3）--HttpRequest 解析（1）

HttpRequest 的解析（1）

从上文中（https://blog.csdn.net/qq_34861102/article/details/80098513）中已经提到对于每一个HttpRequest 要使用一个HttpProcessor用来进行解析，而对于HttpProcessor首先要完成对于传入参数的解析

这里实现一个简易的解析

首先自己写一个打印流的函数，观察输入流中的内容：

    public static void print (InputStream is) throws UnsupportedEncodingException{
        InputStreamReader isr =new InputStreamReader(is,"utf-8");
        BufferedReader br = new BufferedReader(isr);
        try {
            int index = 0;
            while (index < 100) {
                System.out.println(br.readLine());
                index ++;
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

得到内容如下：

GET /index.html?user=outlier HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.87 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8
Cookie: Idea-c03939ae=62b06f69-204a-4fa1-8f13-0c23db6987dd; UM_distinctid=162ec462706246-04cad68b914a44-336e7b05-fa000-162ec46270921b; CNZZDATA1264021086=2075159346-1524378005-%7C1524583190

开始对内容进行解析

新建一个parseRequest方法（这里暂定使用类似于解释器中的Map进行存储得到解析的值）

//常规参数Map
private Map<String,String> paramMap = new HashMap<String, String>();
//在URI中使用的参数列表
private Map<String,String> uriParamMap = new HashMap<String, String>();

进行分析：这里使用递归子程序的方法进行解析

仿照之前的方法，先转化成char类型的数组

public char[] convertStreamToCharArray(InputStream is) {
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();
    String line = null;
    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line + " ");
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return sb.toString().toCharArray();
}

然后进行递归子程序的方法 ，这里先实现的第一行的解析：

package Connector;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

public class HttpRequest {

    //the param
    private Map<String,String> paramMap = new HashMap<String, String>();
    //the param in the URI
    private Map<String,String> uriParamMap = new HashMap<String, String>();
    //the tokens of the inputStream
    char[] tokens;
    //the offset of the tokens
    int currentToken = -1;
    //the value of the token
    char current;

    /*
     * get the tokens
     */
    public HttpRequest(InputStream inputStream) {
        tokens = convertStreamToCharArray(inputStream);
    }

    /*
     * get the URI
     */
    public String getRequestURI() {
        System.out.println("paramMap.size() " + paramMap.size());
        return paramMap.get("requestURI");
    }

    /*
     * the next token
     */
    private void nextToken(){
        if (currentToken < tokens.length){
            currentToken ++;
            current = tokens[currentToken];
        } else {
            // TODO: error message need
            System.out.println("the end of the tokens");
        }
    }
    /*
     * parse
     */
    public void parseRequest(){
        if (tokens == null || tokens.length == 0){
            // TODO: error message need
            System.out.println("the input is null");
            return;
        }
        // start
        nextToken();
        if (current == 'G'){
            parseGetMethod();
        } else if (current == 'P'){

        } else {
            // TODO: error message need
            System.out.println("the input is wrong");
            return;
        }
    }

    /*
     * parse Get
     */
    private void parseGetMethod(){
        nextToken();
        if (current == 'E'){
            nextToken();
            if (current == 'T'){
                paramMap.put("METHOD","GET");
                // TODO: current message need
                System.out.println("the method : get");
                parseURI();
            } else {
                // TODO: error message need
                System.out.println("the method is wrong");
            }
        } else {
            // TODO: error message need
            System.out.println("the method is wrong");
        }
    }


    /*
     * parse URI
     */
    private void parseURI(){
        nextToken();
        while (current == ' ' || current == '\t'){
            nextToken();
        }
        if (current != '/'){
            // TODO: error message need
            System.out.println("there need a '/' , The URI is wrong");
        } else {
            StringBuilder sb = new StringBuilder();
            nextToken();
            while (current != '?' && current != ' '){
                sb.append(current);
                nextToken();
            }
            paramMap.put("requestURI", String.valueOf(sb));
            // TODO: current message need
            System.out.println("the requestURI :" + String.valueOf(sb));
            if (current == ' '){
                // There is no param in the request Param
                // TODO: current message need
                System.out.println("There is no param in the request Param");
                parseHttpVersion();
            } else {
                // TODO: current message need
                System.out.println("There is some params in the request Param");
                parseParamUriRequest();
                System.out.println("params have been recorded");
                parseHttpVersion();
            }
        }
    }

    /*
     * parse the param of the uriRequest
     */
    private void parseParamUriRequest(){
        StringBuilder sb_key = new StringBuilder();
        StringBuilder sb_value = new StringBuilder();
        nextToken();
        while (current != '='){
            sb_key.append(current);
            nextToken();
        }
        nextToken();
        while (current != '&' && current != ' '){
            sb_value.append(current);
            nextToken();
        }
        uriParamMap.put(String.valueOf(sb_key),String.valueOf(sb_value));
        // TODO: current message need
        System.out.println(" params in the URI :  " +String.valueOf(sb_key)+ " : " +String.valueOf(sb_value));
        if (current == '&'){
            parseParamUriRequest();
        }
    }

    /*
     * parse the version of the Http
     */
    private void parseHttpVersion(){
        nextToken();
        while (current == ' ' || current == '\t'){
            nextToken();
        }
        if (current == 'H'){
            StringBuilder sb_key = new StringBuilder();
            StringBuilder sb_value = new StringBuilder();
            while (current != '/'){
                sb_key.append(current);
                nextToken();
            }
            nextToken();
            while (current != '\n' && current != '\t' && current != ' '){
                sb_value.append(current);
                nextToken();
            }
            paramMap.put(String.valueOf(sb_key),String.valueOf(sb_value));
            // TODO: current message need
            System.out.println(" HTTP Version : " +String.valueOf(sb_key)+ " : " +String.valueOf(sb_value));
            nextToken();
            // TODO: 下一次分析开始  H
//            System.out.println(current);
        }
    }

    /*
     * change the inputStream to the CharArray
     */
    private char[] convertStreamToCharArray(InputStream is) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();
        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + ' ');
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString().toCharArray();
    }

}

运行结果：

这里写图片描述

git地址：https://github.com/Outliwer/SimpledWebContainer

一个简单的servlet容器实现（3）--HttpRequest 解析（1）

HttpRequest 的解析（1）

开始对内容进行解析

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