java 入门从零基础到手写服务器

package com.bjsxt.server;

/**<servlet>

<servlet-name>login</servlet-name>

<servlet-class>/com.bjsxt.servlet.LoginServlet.java</servlet-class>

</servlet>

* servlet-name和一个servlet-name所对应的一个实体类

* @author guohaifeng

*描述的是别名和Servlet之间的关系

*/

public class Entity {

private String name;//servlet-name

private String clazz;//servlet-class

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getClazz() {

return clazz;

}

public void setClazz(String clazz) {

this.clazz = clazz;

}

public Entity(String name, String clazz) {

super();

this.name = name;

this.clazz = clazz;

}

public Entity() {

super();

}

}

package com.bjsxt.server;

/**

* <servlet-mapping>

<servlet-name>login</servlet-name>

<url-pattern>/login</url-pattern>

</servlet-mapping>

<servlet-mapping>

<servlet-name>login</servlet-name>

<url-pattern>/log</url-pattern>

</servlet-mapping>

* @author guohaifeng

*映射关系，多个路径访问共享资源

*/

import java.util.ArrayList;

import java.util.List;

public class Mapping {

private String name; //servlet-name

private List<String>urlPattern;//servlet-pattern

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public List<String> getUrlPattern() {

return urlPattern;

}

public void setUrlPattern(List<String> urlPattern) {

this.urlPattern = urlPattern;

}

public Mapping(String name, List<String> urlPattern) {

super();

this.name = name;

this.urlPattern = urlPattern;

}

public Mapping() {

urlPattern=new ArrayList<String>();

}

}

package com.bjsxt.server;

/**

* 请求

* @author guohaifeng

*

*/

import java.io.IOException;

import java.io.InputStream;

import java.io.UnsupportedEncodingException;

import java.net.URLDecoder;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import org.omg.CosNaming.NamingContextExtPackage.URLStringHelper;

public class Request {

//输入流

private InputStream is;

//请求的字符串,请求方式,请求路径,参数,协议，请求正文，

private String requestInfo;

//请求的方式

private String method; //请求的路径

//请求的url

private String url;

//输入框的name为键，值为Value

private Map<String,List<String>>parametermapValues;//参数

private Map<String, List<String>> paramtermapValuesMap;

private static final String CRLF="rn"; //换行

private static final String BLANK="" ;//空格

//构造方法，开始初始化属性

public Request() {

parametermapValues=new HashMap<String, List<String>>();

method="";

url="";

requestInfo="";

}

public Request(InputStream is) {

this(); //调用本类无参的构造方法来为本类初始化

this.is=is;

try {

byte[]buf=new byte[20480];

int len=this.is.read(buf);

requestInfo=new String(buf, 0,len);

} catch (IOException e) {

return;

}

this.PaseRequestInfo();

}

//分解请求信息的方法

private void PaseRequestInfo() {

String paraString = null;

//获取请求参数的第一行

//从0开始，到第一个换行的位置

String firstLine=requestInfo.substring(0,requestInfo.indexOf(CRLF)).trim();

//分解出请求方式

int index=firstLine.indexOf("/");

this.method=firstLine.substring(0,index).trim();

//分解url 可能包含参数，也可能不包含参数post

String uString=firstLine.substring(index,firstLine.indexOf("HTTP")).trim();

//判断请求方式是GET还是POST

//包含请求参数

if("get".equalsIgnoreCase(this.method)) {

if(uString.contains("?")) {

String[]urlArray=uString.split("?");

this.url=urlArray[0];

paraString=urlArray[1];

}else {

this.url=uString;

}

}else {//post不包含请求参数

this.url=uString;

paraString=requestInfo.substring(requestInfo.lastIndexOf(CRLF)).trim();

}

if (paraString.equals("")) {

return;

}

//请求参数

System.out.println(paraString);

//调用本类中分析分解请求参数的方法

this.parseParm(paraString);

}

//用于测试

public void show() {

System.out.println(this.url);

System.out.println(this.method);

}

private void parseParm(String prarString) {

String[] token=prarString.split("&");

for(int i=0;i<token.length;i++) {

String keValues=token[i];

//username bjsxt pwd 123

String []keyValue=keValues.split("=");

if(keyValue.length==1) {

keyValue=Arrays.copyOf(keyValue, 2);

keyValue[1]=null;

}

//将 表单元素的name与name对应的值存储到Map集合中

String key=keyValue[0].trim();

///String value=keyValue[1]==null?null:keyValue[1].trim();

String value=keyValue[1]==null?null:decode(keyValue[1].trim(), "UTF-8");

if(!parametermapValues.containsKey(key)) {

parametermapValues.put(key,new ArrayList<String>());

}

List<String>values=parametermapValues.get(key);

values.add(value);

}

}

//根据表单元素的name获取多个值

private String[] getParamterValues(String name) {

List<String>values=parametermapValues.get(name);

if(values==null) {

return null;

}else {

return values.toArray(new String[0]);

}

}

//根据表单元素的name获取单个值

private String getParamter(String name) {

//调用本类中根据name获取多个值的方法

String[]value=this.getParamterValues(name);

if(value==null) {

return null;

}else {

return value[0];

}

}

//处理中文 因为浏览器对中文进行编码，进行解密

private String decode(String value,String code) {

try {

return URLDecoder.decode(value, code);

} catch (UnsupportedEncodingException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

public static void main(String []args) {

Request req=new Request();

//调用分解参数的方法

req.parseParm("username=%E5%A4%A7%E6%B2%99%E5%9C%B0%E5%A4%9A%E6%89%80&password=%E5%A4%A7%E8%90%A8%E8%BE%BE&hobby=JAVA&hobby=Python&hobby=%E5%A4%A7%E6%95%B0%E6%8D%AE");

System.out.println(req.parametermapValues);

//调用获取多个值的方法

String []str=req.getParamterValues("hobby");

for(String string:str) {

System.out.println(string);

}

//调用获取单个值的方法

System.out.println(req.getParamter("username"));

}

}

package com.bjsxt.server;

/**

* 响应

* @author guohaifeng

*

*/

import java.io.BufferedWriter;

import java.io.OutputStream;

public class Respose {

private StringBuilder headInfo; //响应头

private StringBuilder content; //响应内容

private int length; //响应内容长度

private static final String CRLF=""; //换行

private static final String BLANK=""; //空格

//流

private BufferedWriter bw;

public Respose(StringBuilder headInfo, StringBuilder content, int length, BufferedWriter bw) {

super();

this.headInfo = headInfo;

this.content = content;

this.length = length;

this.bw = bw;

}

//无参构造方法

public Respose() {

headInfo=new StringBuilder();

content=new StringBuilder();

}

//带参构造

public Respose(OutputStream os) {

this(); //调用本类的无参构造方法

}

}

package com.bjsxt.server;

import java.io.BufferedWriter;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStreamWriter;

import java.net.ServerSocket;

import java.net.Socket;

/**

* 用于启动和停止服务

* @author guohaifeng

*

*/

public class Server {

private ServerSocket server;

public void start() {

this.start(8888); //创建服务器对象

}

public void start(int port) {

try {

server=new ServerSocket(port);

this.receive(); //调用接收请求信息的方法

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

//调用接收请求信息的方法

private void receive() {

try {

//监听数据的方法

Socket client=server.accept();

//获取用户的请求

// InputStream is=client.getInputStream();

// byte[]buf=new byte[20480];

// int len=is.read(buf);

// System.out.println(new String(buf, 0,len));

//封装请求信息

Request request=new Request(client.getInputStream());

//request.show();

/**

* 作出响应

*/

StringBuilder sb=new StringBuilder();

sb.append("HTTP/1.1").append(" ").append(200).append(" ").append("OK").append("rn");

sb.append("Content-Type:text/html;charset=utf-8").append("rn");

//内容

String str="<html><head><title>响应结果</title></head><body>成功</body></html>";

sb.append("Content-Length:"+str.getBytes("utf-8").length).append("rn");

sb.append("rn");

sb.append(str);

//通过输出流发送

BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(client.getOutputStream(),"utf-8"));

bw.write(sb.toString());

bw.flush();

bw.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public void stop() {

}

public static void main(String[] args) {

Server server=new Server();

server.start();

}

}

package com.bjsxt.server;

import java.util.HashMap;

import java.util.Map;

/**

* Entity与Mapping的映射关系

* @author guohaifeng

*servlet上下文 就是一个容器

*/

public class ServletContext {

//key是servlet-name（entity中的name），值是servlet-class（entity中的clazz）

private Map<String,String>servlet;

//key是url-patten(Mapping中的List集合中的每一个元素)，值是servlet-name（Mapping中的name）

private Map<String, String>mapping;

public Map<String, String> getServlet() {

return servlet;

}

public void setServlet(Map<String, String> servlet) {

this.servlet = servlet;

}

public Map<String, String> getMapping() {

return mapping;

}

public void setMapping(Map<String, String> mapping) {

this.mapping = mapping;

}

public ServletContext(Map<String, String> servlet, Map<String, String> mapping) {

super();

this.servlet = servlet;

this.mapping = mapping;

}

public ServletContext() {

servlet=new HashMap<String, String>();

mapping=new HashMap<String, String>();

}

}

package com.bjsxt.server;

import java.util.List;

import java.util.Map;

import com.bjsxt.servlet.Servlet;

/**

* App的意思是应用程序

* @author guohaifeng

*

*/

public class WebApp {

private static ServletContext context;

static {

context=new ServletContext();

//分别获取对应关系的Map集合

Map<String,String>servlet=context.getServlet();

Map<String, String>mapping=context.getMapping();

//创建解析XML文件对象

WebDom4j webDom4j=new WebDom4j();

//开始解析XML

webDom4j.parse(webDom4j.getDocument());

//获取解析XML之后的List集合

List<Entity>entitlist=webDom4j.getEntityList();

List<Mapping>mList=webDom4j.getMappingList();

//将list中的数据存储到Map集合

for (Entity entity : entitlist) {

servlet.put(entity.getName(),entity.getClazz());

}

//System.out.println(servlet);

for (Mapping map : mList) {

//遍历url-pattern的集合

List<String>urlpattern=map.getUrlPattern();

for(String s:urlpattern) {

mapping.put(s, map.getName());

}

}

System.out.println(mapping);

}

/**

* 根据url创建不同的Servlet对象

* @param url

* @return

* @throws

*/

public static Servlet getServlet(String url) {

if (url==null||url.trim().equals("")) {

return null;

}

try {

//如果url正确

//根据url的key获取servlet-name的值 /login,/reg=register

String servletName= context.getMapping().get(url);

//根据servletName得到对应的servlet-class

//得到是一个完整的包名加类名的字符串

String servletClass = context.getServlet().get(servletName);

//使用反射创建Servlet对象

Class<?>clazzClass=Class.forName(servletClass);

//调用无参构造方法创建Servlet对象

Servlet servlet = (Servlet)clazzClass.newInstance();

return servlet;

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (InstantiationException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalAccessException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

public static void main(String[] args) {

System.out.println(getServlet("/log"));

}

}

package com.bjsxt.server;

/**

* 解析XML的类

* @author guohaifeng

*

*/

import java.io.File;

import java.lang.Character.Subset;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

import org.omg.CORBA.PRIVATE_MEMBER;

public class WebDom4j {

//用于存储N多Entity,而每一个Entity都是Servlet-name与servlet-class

private List<Entity>entityList;

//用于存储N多Mapping,而每一个Mapping都是一个Servlet-name与N多个url-pattern

private List<Mapping>mappingList;

public List<Entity> getEntityList() {

return entityList;

}

public void setEntityList(List<Entity> entityList) {

this.entityList = entityList;

}

public List<Mapping> getMappingList() {

return mappingList;

}

public void setMappingList(List<Mapping> mappingList) {

this.mappingList = mappingList;

}

public WebDom4j(List<Entity> entityList, List<Mapping> mappingList) {

super();

this.entityList = entityList;

this.mappingList = mappingList;

}

public WebDom4j() {

entityList=new ArrayList<Entity>();

mappingList=new ArrayList<Mapping>();

}

/**

* 获取Document对象

* @return

*/

public Document getDocument() {

//创建SAXReader对象

try {

SAXReader reader=new SAXReader();

// 调用read方法

return reader.read(new File("src/WEB_INFO/web.xml"));

} catch (DocumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

public void parse(Document doc) {

//获取根元素

Element root=doc.getRootElement();

//获取servlet子元素

for(Iterator<Element> ite=root.elementIterator("servlet");ite.hasNext();) {

Element subElement=ite.next();

//创建一个实体类

//用于存储servlet-name与servlet-class

Entity entity=new Entity();

for (Iterator<Element> subite=subElement.elementIterator();subite.hasNext();) {

//可能是servlet-name也可能是servlet-class

Element ele=subite.next();

if("servlet-name".equals(ele.getName())) {

entity.setName(ele.getText());

}else if ("servlet-class".equals(ele.getName())) {

entity.setClazz(ele.getText());

}

}

entityList.add(entity);

}

// //测试

// for(Entity e:entityList) {

// System.out.println(e.getName()+"t"+e.getClazz());

// }

//解析servletMapping

for (Iterator<Element>ite=root.elementIterator("servlet-mapping");ite.hasNext();) {

//得到每一个Servlet-mapping

Element subele=ite.next();

Mapping mapping=new Mapping();

//解析servlet-mapping下的子元素

for (Iterator<Element>subite=subele.elementIterator();subite.hasNext();) {

Element ele = subite.next();

if("servlet-name".equals(ele.getName())) {

mapping.setName(ele.getText());

}else if ("url-pattern".equals(ele.getName())) {

//获取集合对象，调用集合对象的添加方法，添加元素

mapping.getUrlPattern().add(ele.getText());

}

}

mappingList.add(mapping);

}

// for (Mapping m : mappingList) {

// System.out.println(m.getName());

// for(String str:m.getUrlPattern()) {

// System.out.print(str);

// }

// }

}

// public static void main(String[] args) {

// WebDom4j webDom4j=new WebDom4j();

// webDom4j.parse(webDom4j.getDocument());

// }

}

package com.bjsxt.servlet;

public class LoginServlet extends Servlet {

}

package com.bjsxt.servlet;

/**

* 是所有的请求的Servlet的父类

* @author guohaifeng

*

*/

public class Servlet {

}

package com.bjsxt.util;

import java.io.Closeable;

import java.io.IOException;

/**

* 封装关闭IO流的类

* @author guohaifeng

*

*/

public class IOCloseUtil {

public static void CloseAll(Closeable... able) {

for(Closeable c:able) {

if(c!=null) {

try {

c.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

}

<?xml version="1.0" encoding="UTF-8"?>

<web-app>

<servlet>

<servlet-name>login</servlet-name>

<servlet-class>com.bjsxt.servlet.LoginServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>login</servlet-name>

<url-pattern>/login</url-pattern>

<url-pattern>/log</url-pattern>

</servlet-mapping>

</web-app>