下面是字符串,例如:
"Apple"
我想加零来填充8个字符:
"000Apple"
我该怎么做呢?
下面是字符串,例如:
"Apple"
我想加零来填充8个字符:
"000Apple"
我该怎么做呢?
当前回答
public static String lpad(String str, int requiredLength, char padChar) {
if (str.length() > requiredLength) {
return str;
} else {
return new String(new char[requiredLength - str.length()]).replace('\0', padChar) + str;
}
}
其他回答
这是快速的,适用于任何长度。
public static String prefixZeros(String value, int len) {
char[] t = new char[len];
int l = value.length();
int k = len-l;
for(int i=0;i<k;i++) { t[i]='0'; }
value.getChars(0, l, t, k);
return new String(t);
}
这并不漂亮,但很有效。如果你有apache commons,我建议你使用它
if (val.length() < 8) {
for (int i = 0; i < val - 8; i++) {
val = "0" + val;
}
}
public class LeadingZerosExample {
public static void main(String[] args) {
int number = 1500;
// String format below will add leading zeros (the %0 syntax)
// to the number above.
// The length of the formatted string will be 7 characters.
String formatted = String.format("%07d", number);
System.out.println("Number with leading zeros: " + formatted);
}
}
有人尝试过这个纯Java解决方案吗(没有SpringUtils):
//decimal to hex string 1=> 01, 10=>0A,..
String.format("%1$2s", Integer.toString(1,16) ).replace(" ","0");
//reply to original question, string with leading zeros.
//first generates a 10 char long string with leading spaces, and then spaces are
//replaced by a zero string.
String.format("%1$10s", "mystring" ).replace(" ","0");
不幸的是,这个解决方案只有在字符串中没有空格时才有效。
public static void main(String[] args)
{
String stringForTest = "Apple";
int requiredLengthAfterPadding = 8;
int inputStringLengh = stringForTest.length();
int diff = requiredLengthAfterPadding - inputStringLengh;
if (inputStringLengh < requiredLengthAfterPadding)
{
stringForTest = new String(new char[diff]).replace("\0", "0")+ stringForTest;
}
System.out.println(stringForTest);
}