我正在尝试从这里编译代码：http://www.brackeen.com/javagamebook/#download（第6章）并且遇到了麻烦。我不明白java.util.logging.Logger和log4j是如何协同工作的，但这似乎是个问题。我得到的错误都在log.error()或log.warn()方法调用上。
以下是NetBeans的输出：
init:
deps-clean:
Deleting directory C:\JB\NetBeansProjects\WRServer\build
Deleting directory C:\JB\NetBeansProjects\WRServer\dist
clean:
init:
deps-jar:
Created dir: C:\JB\NetBeansProjects\WRServer\build\classes
Compiling 23 source files to C:\JB\NetBeansProjects\WRServer\build\classes
C:\JB\NetBeansProjects\WRServer\src\com\hypefiend\javagamebook\server\GameServer.java:110: cannot find symbol
symbol : method error(java.lang.String,java.lang.Exception)
location: class java.util.logging.Logger
log.error("error initializing ServerSocket", e);
^
C:\JB\NetBeansProjects\WRServer\src\com\hypefiend\javagamebook\server\GameServer.java:152: cannot find symbol
symbol : method warn(java.lang.String)
location: class java.util.logging.Logger
log.warn("error during serverSocket select(): " + ioe.getMessage());
^
C:\JB\NetBeansProjects\WRServer\src\com\hypefiend\javagamebook\server\GameServer.java:155: cannot find symbol
symbol : method error(java.lang.String,java.lang.Exception)
location: class java.util.logging.Logger
log.error("exception in run()", e);
^
C:\JB\NetBeansProjects\WRServer\src\com\hypefiend\javagamebook\server\GameServer.java:187: cannot find symbol
symbol : method error(java.lang.String)
location: class java.util.logging.Logger
log.error("no gamecontroller for gameNameHash: " + gameNameHash);
^
C:\JB\NetBeansProjects\WRServer\src\com\hypefiend\javagamebook\server\GameServer.java:203: cannot find symbol
symbol : method error(java.lang.String)
location: class java.util.logging.Logger
log.error("error getting GameController directory");
^
C:\JB\NetBeansProjects\WRServer\src\com\hypefiend\javagamebook\server\GameServer.java:223: cannot find symbol
symbol : method warn(java.lang.String)
location: class java.util.logging.Logger
log.warn("class file does not extend GameController: " + file);
^
C:\JB\NetBeansProjects\WRServer\src\com\hypefiend\javagamebook\server\GameServer.java:238: cannot find symbol
symbol : method error(java.lang.String,java.lang.Exception)
location: class java.util.logging.Logger
log.error("Error instantiating GameController from file: " + file, e);
^
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
7 errors
BUILD FAILED (total time: 0 seconds)
以下是本书的代码。我还没有尝试过编辑它。
package com.hypefiend.javagamebook.server;
import com.hypefiend.javagamebook.common.*;
import com.hypefiend.javagamebook.server.controller.*;
import java.nio.channels.*;
import java.util.*;
import java.net.*;
import java.io.*;
import java.util.logging.Logger;
import org.apache.log4j.*;
/**
* GameServer.java
*
* The heart of the framework, GameServer accepts
* incoming client connections and hands them off to
* the SelectAndRead class.
* GameServer also keeps track of the connected players
* and the GameControllers.
*
* @author <a href="mailto:bret@hypefiend.com">bret barker</a>
* @version 1.0
*/
public class GameServer extends Thread {
/** log4j Logger */
private Logger log = Logger.getLogger("GameServer");
/** ServerSocketChannel for accepting client connections */
private ServerSocketChannel sSockChan;
/** selector for multiplexing ServerSocketChannels */
private Selector selector;
/** GameControllers keyed by GameName */
private Hashtable gameControllers;
/** classname prefix used for dynamically loading GameControllers */
private static final String CONTROLLER_CLASS_PREFIX =
"com.hypefiend.javagamebook.server.controller.";
/** players keyed by playerId */
private static Hashtable playersByPlayerId;
/** players keyed by sessionId */
private static Hashtable playersBySessionId;
private boolean running;
private SelectAndRead selectAndRead;
private EventWriter eventWriter;
private static long nextSessionId = 0;
/**
* main.
* setup log4j and fireup the GameServer
*/
public static void main(String args[]) {
BasicConfigurator.configure();
GameServer gs = new GameServer();
gs.start();
}
/**
* constructor, just initialize our hashtables
*/
public GameServer() {
gameControllers = new Hashtable();
playersByPlayerId = new Hashtable();
playersBySessionId = new Hashtable();
}
/**
* init the GameServer, startup our workers, etc.
*/
public void init() {
log.info("GameServer initializing");
loadGameControllers();
initServerSocket();
selectAndRead = new SelectAndRead(this);
selectAndRead.start();
eventWriter = new EventWriter(this, Globals.EVENT_WRITER_WORKERS);
}
/**
* GameServer specific initialization, bind to the server port,
* setup the Selector, etc.
*/
private void initServerSocket() {
try {
// open a non-blocking server socket channel
sSockChan = ServerSocketChannel.open();
sSockChan.configureBlocking(false);
// bind to localhost on designated port
InetAddress addr = InetAddress.getLocalHost();
log.info("binding to address: " + addr.getHostAddress());
sSockChan.socket().bind(new InetSocketAddress(addr, Globals.PORT));
// get a selector
selector = Selector.open();
// register the channel with the selector to handle accepts
SelectionKey acceptKey = sSockChan.register(selector, SelectionKey.OP_ACCEPT);
}
catch (Exception e) {
log.error("error initializing ServerSocket", e);
System.exit(1);
}
}
/**
* Here's the meat, loop over the select() call to
* accept socket connections and hand them off to SelectAndRead
*/
public void run() {
init();
log.info("******** GameServer running ********");
running = true;
int numReady = 0;
while (running) {
// note, since we only have one ServerSocket to listen to,
// we don't need a Selector here, but we set it up for
// later additions such as listening on another port
// for administrative uses.
try {
// blocking select, will return when we get a new connection
selector.select();
// fetch the keys
Set readyKeys = selector.selectedKeys();
// run through the keys and process
Iterator i = readyKeys.iterator();
while (i.hasNext()) {
SelectionKey key = (SelectionKey) i.next();
i.remove();
ServerSocketChannel ssChannel = (ServerSocketChannel) key.channel();
SocketChannel clientChannel = ssChannel.accept();
// add to the list in SelectAndRead for processing
selectAndRead.addNewClient(clientChannel);
log.info("got connection from: " + clientChannel.socket().getInetAddress());
}
}
catch (IOException ioe) {
log.warn("error during serverSocket select(): " + ioe.getMessage());
}
catch (Exception e) {
log.error("exception in run()", e);
}
}
}
/**
* shutdown the GameServer
*/
public void shutdown() {
selector.wakeup();
}
/**
* Return the next available sessionId
*/
public synchronized String nextSessionId() {
return "" + nextSessionId++;
}
/**
* finds the GameController for a given GameName
*/
public GameController getGameController(String gameName) {
return getGameControllerByHash(gameName.hashCode());
}
/**
* finds the GameController for a given GameName hash code
*/
public GameController getGameControllerByHash(int gameNameHash) {
GameController gc = (GameController) gameControllers.get("" + gameNameHash);
if (gc == null)
log.error("no gamecontroller for gameNameHash: " + gameNameHash);
return gc;
}
/**
* Dynamically loads GameControllers
*/
private void loadGameControllers() {
log.info("loading GameControllers");
// grab all class files in the same directory as GameController
String baseClass = "com/hypefiend/javagamebook/server/controller/GameController.class";
File f = new File( this.getClass( ).getClassLoader().getResource(baseClass).getPath());
File[] files = f.getParentFile().listFiles( );
if (files == null) {
log.error("error getting GameController directory");
return;
}
for( int i = 0; ( i < files.length); i++) {
String file = files[i].getName( );
if (file.indexOf( ".class") == -1)
continue;
if (file.equals("GameController.class"))
continue;
try {
// grab the class
String controllerClassName = CONTROLLER_CLASS_PREFIX + file.substring(0, file.indexOf(".class"));
log.info("loading class: " + controllerClassName);
Class cl = Class.forName(controllerClassName);
// make sure it extends GameController
if (!GameController.class.isAssignableFrom(cl)) {
log.warn("class file does not extend GameController: " + file);
continue;
}
// get an instance and initialize
GameController gc = (GameController) cl.newInstance();
String gameName = gc.getGameName();
gc.init(this, getGameConfig(gameName));
// add to our controllers hash
gameControllers.put("" + gameName.hashCode(), gc);
log.info("loaded controller for gameName: " + gameName + ", hash: " + gameName.hashCode());
}
catch (Exception e) {
log.error("Error instantiating GameController from file: " + file, e);
}
}
}
/**
* pass the event on to the EventWriter
*/
public void writeEvent(GameEvent e) {
eventWriter.handleEvent(e);
}
/**
* returns the GameConfig object for the given gameName
*/
public GameConfig getGameConfig(String gameName) {
// todo: implement getGameConfig()
return null;
}
/**
* fetches the Player for a given playerId
*/
public static Player getPlayerById( String id) {
return (Player) playersByPlayerId.get(id);
}
/**
* fetches the Player for a given sessionId
*/
public static Player getPlayerBySessionId(String id) {
return (Player) playersBySessionId.get(id);
}
/**
* add a player to our lists
*/
public static void addPlayer(Player p) {
playersByPlayerId.put(p.getPlayerId(), p);
playersBySessionId.put(p.getSessionId(), p);
}
/**
* remove a player from our lists
*/
public static void removePlayer(Player p) {
playersByPlayerId.remove(p.getPlayerId());
playersBySessionId.remove(p.getPlayerId());
}
}// GameServer
答案 0 :(得分：5)
java.util.logging.Logger没有warn()方法（尽管它有warning()方法）。
但是，org.apache.log4j.Logger确实有一个名为warn()的方法。
您确定要导入正确的课程吗？
答案 1 :(得分：5)
在您的类中导入java.util.logging.Logger似乎会导致问题（编译器尝试针对该编译器进行编译，尽管似乎打算使用log4j Logger类）。
尝试从导入和重新编译中删除java.util.logging.Logger。
编辑： 好吧，我刚从问题中链接的页面中链接的ZIP文件中检查了原始的GameServer.java。它不包含任何java.util.logging.Logger的导入。我猜是这样的：
因此，首先将log4j添加到类路径中，然后从导入中删除java.util.logging.Logger。
答案 2 :(得分：0)
您可以格式化代码吗？ Ti会更具可读性......
您正在尝试在java.util.logger.Logger的实例上调用错误（String，String）方法。没有这样的方法。您应该使用Logger.log（Level.SEVERE，“mesage”），或使用log4J Logger的实例。检查源文件的导入部分......