MathUtil.java
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package com.meishu.util;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Random;
public class MathUtil {
public static String getRandomCode(int randomLength) {
StringBuilder str = new StringBuilder();
Random random = new Random();
for (int i = 0; i < randomLength; i++) {
str.append(random.nextInt(10));
}
return str.toString();
}
public static String getRandomString(int length) {
StringBuilder val = new StringBuilder();
Random random = new Random();
for (int i = 0; i < length; ++i) {
String charOrNum = random.nextInt(3) % 3 == 0 ? "num" : "char";
if ("char".equalsIgnoreCase(charOrNum)) {
int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
val.append((char) (random.nextInt(26) + temp));
} else {
val.append(random.nextInt(10));
}
}
return val.toString();
}
//习题/视频 ==> 秒钟向上取整
public static String ceilSecond(int length) {
return String.valueOf((int) Math.ceil((double) length / 60));
}
//视频秒数处理
public static String vodLength(int i) {
if (i > 60) {
if (i % 60 >= 10) {
return i / 60 + ":" + i % 60;
} else {
return i / 60 + ":0" + i % 60;
}
} else {
if (i % 60 >= 10) {
return "00:" + i;
} else {
return "00:0" + i;
}
}
}
//文件大小处理
public static String fileUnit(int i) {
if (i / 1024 > 1024) {
return String.format("%.2f", (double) i / 1024 / 1024) + "M";
} else {
return String.format("%.2f", (double) i / 1024) + "K";
}
}
//单个题目秒数处理
public static String exerciseLength(int i) {
if (i >= 60 * 60) {
return i / 60 / 60 + "时" + (i - 60 * 60) / 60 + "分" + i % 60 + "秒";
} else if (i >= 60) {
return i / 60 + "分" + i % 60 + "秒";
} else {
return i % 60 + "秒";
}
}
// 除法取整
public static String getAvgIndex(BigDecimal counts, BigDecimal total) {
if (BigDecimal.ZERO.equals(total)) {
return "0";
} else {
return counts.divide(total, RoundingMode.CEILING).stripTrailingZeros().toPlainString();
}
}
//百分比 取整 返回字符串
public static String getPercentAvgIndex(BigDecimal counts, BigDecimal total) {
if (BigDecimal.ZERO.equals(total) || BigDecimal.ZERO.equals(counts)) {
return "0%";
} else {
return counts.multiply(new BigDecimal(100)).divide(total, RoundingMode.CEILING).stripTrailingZeros().toPlainString() + "%";
}
}
//百分比 不带%输出
public static String getPercentAvgIndexWithPercent(BigDecimal counts, BigDecimal total) {
if (BigDecimal.ZERO.equals(total) || BigDecimal.ZERO.equals(counts)) {
return "0";
} else {
return counts.multiply(new BigDecimal(100)).divide(total, RoundingMode.CEILING).stripTrailingZeros().toPlainString();
}
}
//习题序号生成规则 sid 从数据取出某科目某知识点的最大的序号
public static String getExeCode(String sid) {
Integer integer = Integer.valueOf(sid.substring(9));
return sid.substring(0, 9) + (++integer);
}
// 整型a 整型b a/b 向上取整
public static Integer intDivCeil(long a, int b) {
return (int) Math.ceil((double) a / b);
}
// 整型a 整型b a/b 向下取整
public static Integer intDivFloorPercent(long a, int b) {
return (int) Math.floor((double) a * 100 / b);
}
public static Integer getRandomNum(Integer i){
Random random = new Random();
return random.nextInt(i);
}
// public static void main(String[] args) {
// for (int i= 1;i<100;i++){
// System.out.println(getRandomNum(2));
// }
// }
}