我正在写一个服务器程序试图猜测客户端有一个数字。服务器从客户端接收一个低数字和高数字（相隔300），并使用二进制搜索算法最多9次来尝试确定该数字。我在一些测试用例“错误打开客户端服务器”上收到错误。单独运行时，大多数测试用例都会通过，但按顺序运行则不会。我认为这是正确打开和关闭套接字和服务器的问题，但似乎无法搞清楚。这是我的代码：
import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Random;
import java.util.Scanner;
public class GuessingServer {
public static void main(String[] args)
{
try{
ServerSocket server;
server = new ServerSocket( 5150 );
System.out.println("awaiting client...");
Socket client = server.accept();
System.out.println("client connected");
Scanner in = new Scanner ( client.getInputStream() );
PrintWriter out = new PrintWriter( client.getOutputStream(), true );
String first = in.next();
int high = in.nextInt();
int low = Integer.parseInt(first);
boolean serverRun = true;
while(serverRun == true)
{
if(!first.equals("SHUT DOWN"))
{
System.out.println(low);
System.out.println(high);
int bNum = ((high - low) / 2) + low;
out.println(bNum);
System.out.println(bNum);
String temp = in.next();
if(temp.equals("high"))
{
high = bNum;
System.out.println(temp + ": ");
System.out.println(high);
i++;
}
else if(temp.equals("low"))
{
low = bNum;
System.out.println(temp + ": ");
System.out.println(low);
i++;
}
else if(temp.equals("won"))
{
System.out.println(temp);
serverRun = false;
}
else if(temp.equals("lost"))
{
System.out.println(temp);
serverRun = false;
}
}
else
{
serverRun = false;
}
}
client.close();
in.close();
out.close();
server.close();
}
catch(IOException e)
{
}
}
}
这是JUnit测试：
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.net.Socket;
import java.util.NoSuchElementException;
import java.util.Random;
import java.util.Scanner;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runners.MethodSorters;
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class GuessingServerTest {
@Test
public void testReflection() {
Class<?> iClass = GuessingServer.class;
Field[] iFields = iClass.getDeclaredFields();
for (Field f : iFields) {
if (!f.isSynthetic()) {
assertTrue ( "Field \""+f.getName()+"\" should be private", Modifier.isPrivate( f.getModifiers() ));
assertFalse( "Field \""+f.getName()+"\" can't be static", Modifier.isStatic ( f.getModifiers() ));
}
}
}
@BeforeClass
public static void startServer() {
// run server
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
GuessingServer.main( new String[]{ } );
}
});
thread.start();
}
@Before
public void waitTwoSecondsBetweenTests() {
try {
Thread.sleep( 2000 );
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
@Test(timeout=3000)
public void testA_WinningAfter1Try() {
try {
// run client
Socket socket = new Socket( "localhost", 5150 );
Scanner scanner = new Scanner ( socket.getInputStream() );
PrintWriter writer = new PrintWriter( socket.getOutputStream(), true );
writer.println( "101 401" );
// try 1
int actual = scanner.nextInt();
assertEquals( "Incorrect result", 251, actual );
writer.println( "won" );
socket .close();
scanner.close();
}
catch (IOException e) {
e.printStackTrace();
fail( "Error opening client socket" );
}
catch (NoSuchElementException e) {
e.printStackTrace();
fail( "The server didn't return a value" );
}
}
@Test(timeout=3000)
public void testB_WinningAfter2Tries() {
try {
// run client
Socket socket = new Socket( "localhost", 5150 );
Scanner scanner = new Scanner ( socket.getInputStream() );
PrintWriter writer = new PrintWriter( socket.getOutputStream(), true );
writer.println( "37 337" );
// try 1
int actual = scanner.nextInt();
assertEquals( "Incorrect result", 187, actual );
writer.println( "low" );
// try 2
actual = scanner.nextInt();
assertEquals( "Incorrect result", 262, actual );
writer.println( "high" );
// try 3
actual = scanner.nextInt();
assertEquals( "Incorrect result", 224, actual );
writer.println( "high" );
// try 4
actual = scanner.nextInt();
assertEquals( "Incorrect result", 205, actual );
writer.println( "low" );
// try 5
actual = scanner.nextInt();
assertEquals( "Incorrect result", 214, actual );
writer.println( "high" );
// try 6
actual = scanner.nextInt();
assertEquals( "Incorrect result", 209, actual );
writer.println( "high" );
// try 7
actual = scanner.nextInt();
assertEquals( "Incorrect result", 207, actual );
writer.println( "high" );
// try 8
actual = scanner.nextInt();
assertEquals( "Incorrect result", 206, actual );
writer.println( "won" );
socket .close();
scanner.close();
}
catch (IOException e) {
e.printStackTrace();
fail( "Error opening client socket" );
}
catch (NoSuchElementException e) {
e.printStackTrace();
fail( "The server didn't return a value" );
}
}
@Test(timeout=3000)
public void testC_PlayingARandomGame() throws IOException {
final int UPPER = 200;
final int RANGE = 300;
final int TRIES = 9;
final Random random = new Random();
try {
// run client
Socket socket = new Socket( "localhost", 5150 );
Scanner scanner = new Scanner ( socket.getInputStream() );
PrintWriter writer = new PrintWriter( socket.getOutputStream(), true );
int low = random.nextInt( UPPER );
int hi = low + RANGE;
int number = low + random.nextInt( RANGE );
writer.println( low + " " + hi );
int tries = 0;
boolean gameOver = false;
while (!gameOver) {
int guess = scanner.nextInt();
if (guess == number) {
writer.println( "won" );
gameOver = true;
}
else {
if (++tries > TRIES) {
writer.println( "lose" );
gameOver = true;
}
else {
if (guess < number) {
writer.println( "low" );
}
else {
writer.println( "high" );
}
}
}
}
socket .close();
scanner.close();
}
catch (IOException e) {
e.printStackTrace();
fail( "Error opening client socket" );
}
catch (NoSuchElementException e) {
e.printStackTrace();
fail( "The server didn't return a value" );
}
}
@Test(expected = IOException.class)
public void testD_RunsLast_ServerShutsDown() throws IOException {
try {
// running client #1...shuts down server
Socket socket = new Socket( "localhost", 5150 );
PrintWriter writer = new PrintWriter( socket.getOutputStream(), true );
writer.println( "SHUT DOWN" );
socket.close();
}
catch (IOException e) {
e.printStackTrace();
fail( "Error opening client socket" );
}
waitTwoSecondsBetweenTests();
// running client #2...should throw exception (server should have stopped)
new Socket( "localhost", 5150 ).close();
fail( "Socket should not connect after server was shut down" );
}
}