Java、Android 相关工具代码记录

1、生成随机字符串

//length表示生成字符串的长度
public static String getRandomStr(int length) {   
        String source = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        Random random = new Random();
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < length; i++) {
            int number = random.nextInt(source .length());
            sb.append(source .charAt(number));
        }
        return sb.toString();
    }

2、Android检测手机是否安装了某个应用

public static boolean isInstalled(Context context, String packageName) {
        PackageManager pm = context.getPackageManager();
        try {
            pm.getPackageInfo(packageName, PackageManager.GET_ACTIVITIES);
            return true;
        } catch (PackageManager.NameNotFoundException e) {
            return false;
        }
    }

3、字符串相似度判断

public static float getSimilarityRatio(String str, String target) {

        int d[][]; // 矩阵
        int n = str.length();
        int m = target.length();
        int i; // 遍历str的
        int j; // 遍历target的
        char ch1; // str的
        char ch2; // target的
        int temp; // 记录相同字符,在某个矩阵位置值的增量,不是0就是1
        if (n == 0 || m == 0) {
            return 0;
        }
        d = new int[n + 1][m + 1];
        for (i = 0; i <= n; i++) { // 初始化第一列
            d[i][0] = i;
        }

        for (j = 0; j <= m; j++) { // 初始化第一行
            d[0][j] = j;
        }

        for (i = 1; i <= n; i++) { // 遍历str
            ch1 = str.charAt(i - 1);
            // 去匹配target
            for (j = 1; j <= m; j++) {
                ch2 = target.charAt(j - 1);
                if (ch1 == ch2 || ch1 == ch2 + 32 || ch1 + 32 == ch2) {
                    temp = 0;
                } else {
                    temp = 1;
                }
                // 左边+1,上边+1, 左上角+temp取最小
                d[i][j] = Math.min(Math.min(d[i - 1][j] + 1, d[i][j - 1] + 1), d[i - 1][j - 1] + temp);
            }
        }

        return (1 - (float) d[n][m] / Math.max(str.length(), target.length())) * 100F;
    }

 

4、时间转多久之前

public static String getShortTime(String dateStr) {
        String shortstring = null;
        String time = timestampToStr(Long.parseLong(dateStr));
        Date date = getDateByString(time);
        if (date == null) return shortstring;

        long now = Calendar.getInstance().getTimeInMillis();
        long deltime = (now - date.getTime()) / 1000;
        if (deltime > 365 * 24 * 60 * 60) {
            shortstring = (int) (deltime / (365 * 24 * 60 * 60)) + "年前";
        } else if (deltime > 30 * 24 * 60 * 60) {
            shortstring = (int) (deltime / (30 * 24 * 60 * 60)) + "月前";
        }else if (deltime > 24 * 60 * 60) {
            shortstring = (int) (deltime / (24 * 60 * 60)) + "天前";
        } else if (deltime > 60 * 60) {
            shortstring = (int) (deltime / (60 * 60)) + "小时前";
        } else if (deltime > 60) {
            shortstring = (int) (deltime / (60)) + "分前";
        } else if (deltime > 1) {
            shortstring = deltime + "秒前";
        } else {
            shortstring = "1秒前";
        }
        return shortstring;
    }

5、隐藏手机号中间数字为星号

public static String phoneFormat(String str) {
        if (TextUtils.isEmpty(str)) return "";
        if (str.length() < 8) return str;
        String startStr = str.substring(0, 3);
        String endStr = str.substring(7);
        StringBuilder sb = new StringBuilder();
        sb.append(startStr).append("****").append(endStr);
        return sb.toString();
    }

6、证件号中部分间隐藏

public static String phoneIdCardFormat(String phone) {
        if (TextUtils.isEmpty(phone)) return "";
        if (phone.length() < 6) return phone;
        String endStr = "";
        String startStr = "";
        if (phone.length() % 2 == 0) {
            if (phone.length() <= 10) {
                startStr = phone.substring(0, (phone.length() - 5) / 2);
                endStr = phone.substring(phone.length() - (phone.length() - 1) / 2, phone.length());
            } else {
                startStr = phone.substring(0, (phone.length() - 5) / 2);
                endStr = phone.substring(phone.length() - (phone.length() - 10) / 2, phone.length());
            }
        } else {
            if (phone.length() <= 10) {
                startStr = phone.substring(0, (phone.length() - 1 - 4) / 2);
                endStr = phone.substring(phone.length() - (phone.length()) / 2, phone.length());
            } else {
                startStr = phone.substring(0, (phone.length() - 1 - 4) / 2);
                endStr = phone.substring(phone.length() - (phone.length() + 1 - 11) / 2, phone.length());
            }
        }

        StringBuilder sb = new StringBuilder();
        sb.append(startStr).append("****").append(endStr);
        return sb.toString();
    }

 

// cmd 查看当前Android设备的 CPU 架构

adb shell getprop ro.product.cpu.abi