java 字符串中截取英文部分

话不多说，上代码：
提取英文部分

public static String extractEn(String s1) {
        StringBuilder sb = new StringBuilder(s1);
        (0, ()).forEach(k -> {
            char c = (k);
            if (!isChinese(c))
                (c);
        });
        return ().substring((), ());
    }

其中调用了一个网上的函数，判断是不是中文

private static boolean isChinese(char c) {
     ub = (c);
    return ub == .CJK_UNIFIED_IDEOGRAPHS
            || ub == .CJK_COMPATIBILITY_IDEOGRAPHS
            || ub == .CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
            || ub == .GENERAL_PUNCTUATION
            || ub == .CJK_SYMBOLS_AND_PUNCTUATION
            || ub == .HALFWIDTH_AND_FULLWIDTH_FORMS;
}

另：判断字符是不是汉字

    public static boolean isChineseChar(char c) {
        return (c).matches("[\u4e00-\u9fa5]");
    }