拿java的web开发为例子，相信有很多小伙伴是做j2EE开发的，htpp请求，json数据传输都是工作中经常用的，查询请求，添加请求，修改请求前端配个url，例如https://localhost/intsmaze/user/add?name=intsmaze。然后后端建立一个controler类（类上配置url映射/user），然后创建一个addUser方法(在方法上配置映射/add)。然后启动web应用，前端发送的请求就会自动走到后端的addUser方法了。
但是你知道为什么这个请求走对应的方法吗？下面让我拿我大三期间基于TCP写的服务端程序做例子来看看背后的原理吧。这个程序时一个超市管理系统，客户端使用javaSwing编写，服务端使用javaSE编写，双方通信使用TCP协议，数据存储在mysql中。完整的项目上传在github上https://github.com/intsmaze/Swing-TCP-mysql。
服务端启动类，绑定端口。
public class LoginServer {
private int port=1000;
private ServerSocket serversocket;
private ExecutorService executorservice;
private final int POOL_SIZE=1;//一个CPU线程池中工作线程的数目
public LoginServer() throws Exception
{
serversocket=new ServerSocket();
serversocket.bind(new InetSocketAddress("127.0.0.1",port));
executorservice=Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()*POOL_SIZE);
//当前CPU数*1就是总线程池数目
}
public void service()
{
while(true)
{
Socket socket=null;
try
{
socket=serversocket.accept();
executorservice.execute(new Handler(socket));
}catch(IOException e)
{
e.printStackTrace();
}
}
}
public static void main(String[] args) throws Exception {
new LoginServer().service();
}
}
路径映射方法
localhost/intsmaze/后面不同的路径就是截取对应的字符串然后调用对应的方法
public class Handler implements Runnable{
public static final int SOLDERCONNECTION=0;//售货员登录
public static final int MANAGERADDSOLDER=7;//管理员添加售货员
public static final int MANAGERDELETESOLDER=8;//管理员删除售货员
public static final int MANAGERMOIDFYSOLDER=9;//管理员修改售货员
private Socket socket;
private BufferedReader bufIn=null;
private BufferedWriter bufOut=null;
private Connection connection=null;
private PreparedStatement preparedstatement=null;
private ResultSet resultset=null;
public Handler(Socket socket) throws IOException
{
this.socket=socket;
bufIn=new BufferedReader(new InputStreamReader(socket.getInputStream()));
bufOut=new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
}
public void run()
{
try
{
String line=bufIn.readLine();
//读取第一个选着功能
int i=Integer.valueOf(line);
switch(i)
{
case SOLDERCONNECTION:
solderConnection();//售货员登录0
break;
case MANAGERADDSOLDER:
managerAddSolder();//管理员添加售货员7
break;
case MANAGERDELETESOLDER:
managerDeleteSolder();//管理员删除售货员8
break;
case MANAGERMOIDFYSOLDER:
managerModifySolder();//管理员修改售货员9
break;
}
}catch(Exception e)
{
socketUtil.close(socket);
}
}
public void solderConnection() throws Exception
{
String sr=null;
//读取账号和密码
String arr[] =bufIn.readLine().split("#");;
connection=JdbcUtil.getConnection();
preparedstatement=connection.prepareStatement("SELECT * FROM solder WHERE solder_number=? and solder_password=?");
preparedstatement.setString(1,arr[0]);
preparedstatement.setString(2,arr[1]);
resultset=preparedstatement.executeQuery();
if(resultset.next()){
bufOut.write("ok\n");//回馈查询信心
bufOut.flush();
sr=resultset.getInt(1)+"#"+resultset.getString(2)+"#"+resultset.getString(3)+"\n";
bufOut.write(sr);
bufOut.flush();
}
else
{
bufOut.write("no");//回馈查询信心
bufOut.flush();
}
JdbcUtil.release(resultset, preparedstatement, connection);
}
public void managerAddSolder() throws Exception
{
connection=JdbcUtil.getConnection();
String name=bufIn.readLine();
System.out.println(name);
preparedstatement=connection.prepareStatement("insert into solder(solder_name) values(?) ");
preparedstatement.setString(1,name);
preparedstatement.executeUpdate();//执行更新
preparedstatement=connection.prepareStatement("select *from solder where solder_number=(select MAX(solder_number)from solder) ");
resultset=preparedstatement.executeQuery();//执行更新
if(resultset.next())
{
bufOut.write("ok\n");//回馈查询信心
bufOut.flush();
String str=resultset.getString(1)+"#"+resultset.getString(2)+"#"+resultset.getString(3);
bufOut.write(str+"\n");//回馈查询信心
bufOut.flush();
}
else
{
bufOut.write("no\n");//回馈查询信心
bufOut.flush();
}
JdbcUtil.release(resultset, preparedstatement, connection);
}
public void managerModifySolder() throws Exception
{
connection=JdbcUtil.getConnection();
String arr[] = null;
String line=null;
String number=bufIn.readLine();
preparedstatement=connection.prepareStatement("select *from solder WHERE solder_number=? ");
preparedstatement.setString(1,number);
resultset=preparedstatement.executeQuery();
if(resultset.next())
{
bufOut.write("ok\n");//回馈查询信心
bufOut.flush();
line=bufIn.readLine();
arr=line.split("#");
preparedstatement=connection.prepareStatement("update solder set solder_password=?,solder_name=? WHERE solder_number=? ");
preparedstatement.setString(1,arr[2]);
preparedstatement.setString(2,arr[1]);
preparedstatement.setString(3,arr[0]);
preparedstatement.executeUpdate();//执行更新
}
else
{
bufOut.write("no\n");//回馈查询信心
bufOut.flush();
}
socket.close();
JdbcUtil.release(resultset, preparedstatement, connection);
}
public void managerDeleteSolder() throws Exception
{
connection=JdbcUtil.getConnection();
String number=bufIn.readLine();
preparedstatement=connection.prepareStatement("select *from solder WHERE solder_number=? ");
preparedstatement.setString(1,number);
resultset=preparedstatement.executeQuery();
if(resultset.next())
{
bufOut.write("ok\n");//回馈查询信心
bufOut.flush();
preparedstatement=connection.prepareStatement("delete from solder WHERE solder_number=? ");
preparedstatement.setString(1,number);
preparedstatement.executeUpdate();//执行更新
}
else
{
bufOut.write("no\n");//回馈查询信心
bufOut.flush();
}
socket.close();
JdbcUtil.release(resultset, preparedstatement, connection);
}
}
以localhost/intsmaze/user/add?name=intsmaze的url来反向剖析tcp服务端如何接收，并调用对应方法。localhost是与服务器建立连接，然后发送intsmaze/user/add?name=intsmaze为一个数据到服务器，服务器接收到该字符串后，根据/截取，然后判断该请求是发给intsmaze的应用。然后通过user知道这个请求时user模块（用户管理模块），然后通过add知道是调用添加用户方法。?后面就是对于的参数获取存入数据库即可.
对上面的方法改进如下即可实现
String line=bufIn.readLine();
//读取第一个选着功能 line的值为intsmaze/user/add?name=intsmaze
String arr[]=line.split("/");
String model=arr[1];
String method=arr[2].split("?")[0];
String param=arr[2].split("?")[1];
if(model.endsWith("user"))
{
if(method.equals("add"))
{
user.add(param);
}
}
else if(model.equals("goods"))
{
...
}
else if
...
老铁，你的--->推荐，--->关注,--->评论--->是我继续写作的动力。
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