Java代码实现输入一段代码，当输入exit停止，统计这段代码中的各个关键词个数，需要再创建一个方法除去代码中的注释部分

好的，以下是 Java 实现代码：

import java.util.HashMap;
import java.util.Scanner;

public class KeywordCounter {
    // Java 关键词
    private static final String[] KEYWORDS = new String[] {
        "abstract", "assert", "boolean", "break", "byte", "case", "catch",
        "char", "class", "const", "continue", "default", "do", "double",
        "else", "enum", "extends", "final", "finally", "float", "for",
        "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"
    };

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        StringBuilder code = new StringBuilder();
        String line;
        while (!(line = scanner.nextLine()).equals("exit")) {
            code.append(line).append('\n');
        }
        scanner.close();

        // 计算关键词数量
        HashMap<String, Integer> keywordCount = countKeywords(code.toString());
        System.out.println("关键词数量统计结果：");
        for (String keyword : keywordCount.keySet()) {
            System.out.println(String.format("%-15s: %d", keyword, keywordCount.get(keyword)));
        }
    }

    private static HashMap<String, Integer> countKeywords(String code) {
        HashMap<String, Integer> keywordCount = new HashMap<>();
        code = removeComments(code);
        String[] words = code.split("\\W+");  // 以非单词字符为分隔符
        for (String word : words) {
            if (isKeyword(word)) {
                keywordCount.put(word, keywordCount.getOrDefault(word, 0) + 1);
            }
        }
        return keywordCount;
    }

    private static boolean isKeyword(String word) {
        for (String keyword : KEYWORDS) {
            if (keyword.equals(word)) {
                return true;
            }
        }
        return false;
    }

    private static String removeComments(String code) {
        // 匹配单行注释和多行注释
        code = code.replaceAll("//.*", "");
        code = code.replaceAll("/\\*.*?\\*/", "");
        return code;
    }
}

该程序首先会循环读入用户输入的代码，直到用户输入 `exit`。然后，调用 `countKeywords` 方法统计代码中各个关键词的数量，并输出结果。

`countKeywords` 方法会先调用 `removeComments` 方法去除代码中的注释部分，然后使用正则表达式分割代码为单词，判断每个单词是否为 Java 关键词，最终统计出每个关键词的数量。

`removeComments` 方法使用正则表达式匹配单行注释和多行注释，并将其替换为空字符串。

注意：该程序只能处理不带语法错误的代码。