用到了几个类
Contants 常量类
HttpServlet1 启动类(使用ServerSocket监听端口，并进行分发处理)
PrimitiveServlet (被处理的javax.servlet.Servlet类)
Request类 (处理客户端传来的请求)
Response类 (处理返回给客户端的请求,这里是返回静态资源)
ServletProcess1 (处理servlet)
StaticResourceProcessor (处理静态资源)
Constants.java 静态类,存放静态变量，这里不放代码了
HttpServer1.java
public class HttpServer1 {
private static final String SHUTDOWN_COMMAND="/SHUTDOWN";
private boolean shutdown=false;
public static void main(String[] args) {
HttpServer1 server=new HttpServer1();
server.await();
}
private void await() {
int port=8080;
try(ServerSocket serverSocket=new ServerSocket(port,
1, InetAddress.getByName("127.0.0.1"))){
while (!shutdown){
Socket socket=serverSocket.accept();
InputStream input=socket.getInputStream();
OutputStream output=socket.getOutputStream();
Request request=new Request(input);
request.parse();
Response response=new Response(output);
response.setRequest(request);
//response.sendStaticResource();
//处理uri
if(request.getUri().startsWith("/servlet/")){
ServletProcess1 process=new ServletProcess1();
process.process(request,response);
}else {
StaticResourceProcessor processor=
new StaticResourceProcessor();
processor.process(request,response);
}
socket.close();
shutdown=request.getUri().equals(SHUTDOWN_COMMAND);
}
}catch (Exception e){
e.printStackTrace();
System.exit(1);
}
}
}
PrimitiveServlet
public class PrimitiveServlet implements Servlet {
@Override
public void init(ServletConfig servletConfig) throws ServletException {
System.out.println("init");
}
@Override
public ServletConfig getServletConfig() {
return null;
}
@Override
public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
System.out.println("from service");
PrintWriter printWriter=servletResponse.getWriter();
//注意,这里要加http头信息,要不chrome会认为请求失败
String head="HTTP/1.1 200 OK\r\n"+
"Content-Type: text/html\r\n\r\n";
printWriter.println(head);
printWriter.println("Hello. Roses are red.");
printWriter.println("Violets are blue.");
printWriter.flush();
}
@Override
public String getServletInfo() {
return null;
}
@Override
public void destroy() {
System.out.println("destroy");
}
}
Request.java
public class Request implements ServletRequest {
private InputStream input;
private String uri;
public Request(InputStream inputStream) {
this.input=inputStream;
}
public void parse() {
StringBuffer request=new StringBuffer(2048);
int i;
byte[] buffer=new byte[2048];
try{
//这里返回读取的实际字节的大小
i=input.read(buffer);
}catch (IOException e){
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());
}
/**
* 获取uri
* @param requestString
* @return
*/
private String parseUri(String requestString){
int index1,index2;
index1=requestString.indexOf(' ');
if(index1 != -1){
index2=requestString.indexOf(' ',index1+1);
if(index2 > index1){
//截取http请求的rui
return requestString.substring(index1+1,index2);
}
}
return null;
}
public String getUri() {
return uri;
}
//----省略一些继承方法------
}
RequestFacade .java
/**
* 可以保护外界调用不到servletRequest
* 保护request类的公共方法
*/
public class RequestFacade implements ServletRequest {
private ServletRequest request=null;
public RequestFacade(ServletRequest request){
this.request=request;
}
@Override
public Object getAttribute(String s) {
return request.getAttribute(s);
}
//-----省略一些继承方法------
}
Response .java
public class Response implements ServletResponse {
private static final int BUFFER_SIZE=1024;
Request request;
OutputStream output;
PrintWriter writer;
public Response(OutputStream outputStream) {
this.output=outputStream;
}
public void setRequest(Request request) {
this.request=request;
}
public PrintWriter getWriter(){
writer=new PrintWriter(output);
return writer;
}
public void sendStaticResource() throws IOException {
byte[] bytes=new byte[BUFFER_SIZE];
FileInputStream fis=null;
try {
File file=new File(Constants.WEB_ROOT,request.getUri());
if(file.exists()){
fis=new FileInputStream(file);
int ch=fis.read(bytes,0,BUFFER_SIZE);
//注意 这里一定要添加响应返回头信息,否则chrome不无打开,
//会出现ERR_INVALID_HTTP_RESPONSE
String head="HTTP/1.1 200 OK\r\n"+
"Content-Type: text/html\r\n\r\n";
output.write(head.getBytes());
while (ch!=-1){
output.write(bytes,0,ch);
//一次性读取部分字节
ch=fis.read(bytes,0,BUFFER_SIZE);
}
output.flush();
}else {
//文件不存在
String errorMessage="HTTP/1.1 404 FileNot Found\r\n"+
"Content-Type: text/html\r\n"+
"Content-Length:23\r\n"+
"\r\n"+
"<h1>File Not Found</h1>";
output.write(errorMessage.getBytes());
}
}catch (Exception e){
System.out.println(e.toString());
}finally {
if(fis!=null){
fis.close();
}
}
}
//---省略一些继承方法---
ServletProcess1.java servlet处理器
public class ServletProcess1 {
public void process(Request request, Response response) {
String uri=request.getUri();
String servletName=uri.substring(uri.lastIndexOf("/")+1);
servletName="com.ly3."+servletName;
URLClassLoader loader=null;
try {
URL[] urls=new URL[1];
URLStreamHandler streamHandler=null;
File classPath=new File(Constants.WEB_ROOT);
String repository=
(new URL("file",null,classPath.getCanonicalPath()+
File.separator)).toString();
urls[0]=new URL(null,repository,streamHandler);
loader=new URLClassLoader(urls);
}catch (IOException e){
System.out.println(e.toString());
}
Class myClass=null;
try {
System.out.println(servletName);
myClass=loader.loadClass(servletName);
Servlet servlet=(Servlet)myClass.newInstance();
RequestFacade requestFacade=new RequestFacade(request);
servlet.service(requestFacade,(ServletResponse)response);
}catch (Exception e){
e.printStackTrace();
}
}
}
静态资源处理器
public class StaticResourceProcessor {
public void process(Request request, Response response) {
try {
response.sendStaticResource();
} catch (IOException e) {
e.printStackTrace();
}
}
}
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