如何修改Java Scanner中正确输入内容的显示颜色？

核心问题分析 #

你当前的思路是对的——通过ANSI转义码实现控制台文本变色，但需要调整实现逻辑，避免将带颜色代码的字符串存入集合，同时确保转义码定义正确。

可行优化建议 #

• 定义正确的ANSI颜色转义码
  先在代码中明确绿色和重置的转义常量（你的bien应该对应这个绿色常量）：

  public static final String ANSI_GREEN = "\u001B[32m";
  public static final String ANSI_RESET = "\u001B[0m";
  public static final String ANSI_RED = "\u001B[31m"; // 错误提示用红色
  

• 调整输出与存储逻辑
  不要把带颜色代码的字符串存入acertadas集合（否则后续打印集合时会重复显示颜色代码），应该验证通过后直接打印带颜色的输入内容，再存储原始字符串：

  if(reservadas.contains(palabras)) {
      // 先打印绿色的正确保留字
      System.out.println(ANSI_GREEN + palabras + ANSI_RESET);
      // 存入原始字符串，保证集合数据纯净
      acertadas.add(palabras);
      contador++;
  }
  

• 优化Scanner实例创建
  循环内反复创建Scanner会浪费资源，把实例移到循环外初始化：

  Scanner scanner = new Scanner(System.in);
  while (repetir || contador == max) {
      String palabras = scanner.nextLine().toLowerCase();
      // 后续逻辑...
  }
  scanner.close(); // 循环结束后关闭资源
  

• 处理控制台兼容性
  部分Windows默认CMD不支持ANSI转义码，可通过以下方式解决：

  • 改用PowerShell运行程序（原生支持ANSI）
  • 添加JVM启动参数：-Dconsole.encoding=UTF-8
  • 若需兼容旧版Windows，可使用Jansi第三方库处理颜色

修改后的完整代码示例 #

import java.util.Scanner;
import java.util.List;
import java.util.ArrayList;

public class ReservedWordPractice {
    public static final String ANSI_GREEN = "\u001B[32m";
    public static final String ANSI_RED = "\u001B[31m";
    public static final String ANSI_RESET = "\u001B[0m";

    public static void main(String[] args) {
        boolean repetir = true;
        int contador = 0;
        int max = 0;
        List<String> acertadas = new ArrayList<>();
        // 预定义Java所有保留字集合
        List<String> reservadas = List.of("abstract", "assert", "boolean", "break", "byte", "case", "catch", "char", "class", "const", "continue", "default", "do", "double", "else", "enum", "extends", "final", "finally", "float", "for", "goto", "if", "implements", "import", "instanceof", "int", "interface", "long", "native", "new", "package", "private", "protected", "public", "return", "short", "static", "strictfp", "super", "switch", "synchronized", "this", "throw", "throws", "transient", "try", "void", "volatile", "while");

        Scanner scanner = new Scanner(System.in);
        while (repetir || contador == max) {
            String palabras = scanner.nextLine().toLowerCase();
            
            if (palabras.contains(".")) {
                System.out.println("Has acertado las siguientes palabras: " + acertadas);
                repetir = false;
            } else {
                if(reservadas.contains(palabras)) {
                    System.out.println(ANSI_GREEN + palabras + ANSI_RESET);
                    acertadas.add(palabras);
                    contador++;
                } else {
                    System.out.println(ANSI_RED + "No es correcto" + ANSI_RESET);
                }
                if (contador == 50) {
                    System.out.println("ENHORABUENA!!!");
                    System.out.println("Has acertado todas las palabras reservadas");
                    repetir = false;
                }
            }
        }
        scanner.close();
    }
}

内容的提问来源于stack exchange，提问作者Ivan Parra