java - 将字符串转换为字节时，addr 的长度非法

Question

我正在为一个 friend 编写一个游戏(《我的世界》)的模组。为了执行 mod 的指定功能，我需要确保在特定时间内可以访问服务器，我使用 InetAddress 来执行此操作，但每次使用该命令时都会收到此错误

2012-12-02 18:45:53 [INFO] [STDERR] java.net.UnknownHostException: addr is of illegal length
2012-12-02 18:45:53 [INFO] [STDERR]     at java.net.InetAddress.getByAddress(Unknown Source)
2012-12-02 18:45:53 [INFO] [STDERR]     at java.net.InetAddress.getByAddress(Unknown Source)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.CommandServSwitch.processCommand(CommandServSwitch.java:40)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.CommandHandler.executeCommand(CommandHandler.java:81)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.NetServerHandler.handleSlashCommand(NetServerHandler.java:715)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.NetServerHandler.handleChat(NetServerHandler.java:681)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.Packet3Chat.processPacket(Packet3Chat.java:60)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.MemoryConnection.processReadPackets(MemoryConnection.java:79)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.NetServerHandler.networkTick(NetServerHandler.java:82)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.NetworkListenThread.networkTick(NetworkListenThread.java:55)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.IntegratedServerListenThread.networkTick(IntegratedServerListenThread.java:111)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:696)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:592)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.IntegratedServer.tick(IntegratedServer.java:110)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:499)
2012-12-02 18:45:53 [INFO] [STDERR]     at net.minecraft.src.ThreadMinecraftServer.run(ThreadMinecraftServer.java:17)

生成此错误的方法(以及您需要了解的所有代码):

    @Override
public void processCommand(ICommandSender var1, String[] var2) {
    if(var2.length < 1 || var2.length > 3) {
            throw new WrongUsageException("command.switch.usage", new Object[0]);
    }
    else {
             servport = Integer.parseInt(var2[1]);

            boolean ping = false;
            try {
                InetAddress IP = InetAddress.getByAddress(var2[0].getBytes());
                ping = IP.isReachable(400);
            } catch(UnknownHostException e) {
                e.printStackTrace();
            } catch(IOException e) {
                e.printStackTrace();
            }

Answer 1

getByAddress 的文档说:“返回一个 InetAddress 对象给定原始 IP 地址。参数按网络字节顺序:地址的最高顺序字节位于 getAddress()[0] ”

            InetAddress IP = InetAddress.getByAddress(var2[0].getBytes());

这行代码没有任何意义。该字符串不是函数所需的网络字节顺序的原始 IP 地址。否则，它的长度将恰好是四个字节。

您需要调用InetAddress.getByName从文本字符串(如 foo.domain.com 或 1.2.3.4)转换为内部二进制格式。