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java服务器的简单实现过程记录

2024-04-02 19:55

短信预约 -IT技能 免费直播动态提醒

一、HTTP

http请求

一般一个http请求包括以下三个部分：

1 请求方法，如get,post

2 请求头

3 实体

一个http请求的实例如下：

GET /index.jsp HTTP/1.1

Host: localhost:8080

User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:15.0) Gecko/20100101 Firefox/15.0

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,* public class Request { //输入流 private InputStream input; //截取url,如http://localhost:8080/index.html ，截取部分为 /index.html private String uri; public Request(InputStream inputStream){ this.input = inputStream; } public InputStream getInput() { return input; } public void setInput(InputStream input) { this.input = input; } public String getUri() { return uri; } public void setUri(String uri) { this.uri = uri; } //从套接字中读取字符信息 public void parse(){ StringBuffer request = new StringBuffer(2048); int i = 0; byte[] buffer = new byte[2048]; try { i = input.read(buffer); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); i = -1; } for(int j = 0;j<i;j++){ request.append((char)(buffer[j])); } System.out.println(request.toString()); uri = parseUri(request.toString()); } //截取请求的url private String parseUri(String requestString){ int index1 = 0; int index2 = 0; index1 = requestString.indexOf(' '); if(index1!=-1){ index2 = requestString.indexOf(' ',index1+1); if(index2>index1){ return requestString.substring(index1+1,index2); } } return null; } }

下面是封装了响应请求的类response:


package com.lwq;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;


public class Response {
    
    private static final int BUFFER_SIZE = 1024;
    Request request;
    OutputStream output;
    public Response(OutputStream output){
        this.output = output;
    }
    
    public void sendStaticResource() throws IOException{
        
        byte[] bytes = new byte[BUFFER_SIZE];
        FileInputStream fis = null;
        
        File file = new File(HttpServer.WEB_ROOT,request.getUri());
        if(file.exists()){
            try {
                fis = new FileInputStream(file);
                int ch = fis.read(bytes,0,BUFFER_SIZE);
                while(ch != -1){
                    output.write(bytes,0,ch);
                    ch = fis.read(bytes,0,BUFFER_SIZE);
                }
                
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }catch(IOException e){
                e.printStackTrace();
            }finally{
                if(fis !=null){
                    fis.close();
                }
            }
            
        }else{
            //找不到文件
             String errorMessage = "HTTP/1.1 404 File Not Found\r\n" +
     "Content-Type: text/html\r\n" +
     "Content-Length: 23\r\n" +
     "\r\n" +
     "
File Not Found
";
             try {
                output.write(errorMessage.getBytes());
                output.flush();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    public Request getRequest() {
        return request;
    }
    public void setRequest(Request request) {
        this.request = request;
    }
    public OutputStream getOutput() {
        return output;
    }
    public void setOutput(OutputStream output) {
        this.output = output;
    }
    public static int getBUFFER_SIZE() {
        return BUFFER_SIZE;
    }
}

接下来是主程序，


package com.lwq;

import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;


public class HttpServer {

    
    
    //WEB_ROOT是服务器的根目录
    public static final String WEB_ROOT = System.getProperty("user.dir")+File.separator+"webroot";
    
    //关闭的命令
    private static final String SHUTDOWN_COMMAND= "/SHUTDOWN";
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        HttpServer server = new HttpServer();
        server.await();

    }
    public void await(){
        ServerSocket serverSocket = null;
        int port = 8080;
        try {
            serverSocket = new ServerSocket(port,1,InetAddress.getByName("127.0.0.1"));
            while(true)
            {
                try {
            Socket socket = null;
            InputStream input = null;
            OutputStream output = null;
            socket = serverSocket.accept();
            input = socket.getInputStream();
            output = socket.getOutputStream();
            //封装request请求
            Request request = new Request(input);
            request.parse();
            //封装response对象
            Response response = new Response(output);
            response.setRequest(request);
            response.sendStaticResource();
            socket.close();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    continue;
                }
            
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        
        
    }
    

}

运行httpServer,在浏览器中打下http://localhost:8080/index.jsp,就能看到服务器响应的结果了。