What is @SuppressWarnings(“deprecation”) and how do I fix it?

问题

I am following a YouTube tutorial and I came across this error.

At this line, @SuppressWarnings("deprecation") comes up.

Player targerPlayer = Bukkit.getServer().getPlayer(args[0]);

Here is my simple healing plugin.

package me.roofer.youtube;

import java.util.logging.Logger;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.PluginDescriptionFile;
import org.bukkit.plugin.java.JavaPlugin;

public class youtube extends JavaPlugin {
    public static Logger logger = Logger.getLogger("Minecraft");   
    public static youtube plugin;

    @Override
    public void onDisable() {
        PluginDescriptionFile pdfFile = this.getDescription();
        youtube.logger.info(pdfFile.getName() + " has been disabled!");
    }
    @Override
    public void onEnable() {
        PluginDescriptionFile pdfFile = this.getDescription();
        youtube.logger.info(pdfFile.getName() + " Version" + pdfFile.getVersion() + " has been Enabled!");

    public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args){
        @SuppressWarnings("unused")
        Player player = (Player) sender;
        if(commandLabel.equalsIgnoreCase("heal") || commandLabel.equalsIgnoreCase("h")) {
            // heal >> 0 args | heal roofer777 >> 1 arg
            if (args.length == 0){
                player.setHealth(20);
                player.sendMessage(ChatColor.RED + "Healed!");
            }else if(args.length == 1){
                @SuppressWarnings({"unused", "deprecation"})
                Player targerPlayer = Bukkit.getServer().getPlayer(args[0]);
                targetPlayer.setHealth(20);
            }
        }
        return false;
    }
}

回答1:

That is not an error. You should read up on the definition of deprecation.

A program element annotated @Deprecated is one that programmers are discouraged from using, typically because it is dangerous, or because a better alternative exists. Compilers warn when a deprecated program element is used or overridden in non-deprecated code.

The reason why that specific method is deprecated is because Bukkit is now moving over to the new UUID system, so using names is not the best way to get a Player object.

来源：https://stackoverflow.com/questions/27325391/what-is-suppresswarningsdeprecation-and-how-do-i-fix-it

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java

bukkit

suppress-warnings