java 简单的问题 如何校验我入输的文本是不是数字呀 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 將文本框輸入的文本轉為Double, 然後捕捉異常. 使用formatted类格式化输入即可。Locale[] locales = NumberFormat.getAvailableLocales(); double myNumber = -1234.56; NumberFormat form; for (int j=0; j<4; ++j) { System.out.println("FORMAT"); for (int i = 0; i < locales.length; ++i) { if (locales[i].getCountry().length() == 0) { continue; // Skip language-only locales } System.out.print(locales[i].getDisplayName()); switch (j) { case 0: form = NumberFormat.getInstance(locales[i]); break; case 1: form = NumberFormat.getIntegerInstance(locales[i]); break; case 2: form = NumberFormat.getCurrencyInstance(locales[i]); break; default: form = NumberFormat.getPercentInstance(locales[i]); break; } if (form instanceof DecimalFormat) { System.out.print(": " + ((DecimalFormat) form).toPattern()); } System.out.print(" -> " + form.format(myNumber)); try { System.out.println(" -> " + form.parse(form.format(myNumber))); } catch (ParseException e) {} } } import java.util.regex;public static void isDigital(String data) { Pattern ptn=Pattern.compile("^(-|\\+)?\\d*$"); Matcher mat=ptn.matcher(data); System.out.println(data+" is digitial ?: "+mat.matches()); }不是数字就是取反 高分求解~循环~200分 我的TCP编程怎么在eclipse里无法进行相互发送信息 高手帮改下 急!!!! 一只熊掉进20米的洞,两秒钟到底,问。。。。 求助 java与SNMP的编程!! class or interface expected Java内部类 代码问题 请教包的用法。 equals和==这两种比较方式有什么不同和相同? 递归算法问题,求大神讲解一下为什么 java求10到105以内的质数 怎样实现数据输出打印 怎么判断正在被执行的class的目录
double myNumber = -1234.56;
NumberFormat form;
for (int j=0; j<4; ++j) {
System.out.println("FORMAT");
for (int i = 0; i < locales.length; ++i) {
if (locales[i].getCountry().length() == 0) {
continue; // Skip language-only locales
}
System.out.print(locales[i].getDisplayName());
switch (j) {
case 0:
form = NumberFormat.getInstance(locales[i]); break;
case 1:
form = NumberFormat.getIntegerInstance(locales[i]); break;
case 2:
form = NumberFormat.getCurrencyInstance(locales[i]); break;
default:
form = NumberFormat.getPercentInstance(locales[i]); break;
}
if (form instanceof DecimalFormat) {
System.out.print(": " + ((DecimalFormat) form).toPattern());
}
System.out.print(" -> " + form.format(myNumber));
try {
System.out.println(" -> " + form.parse(form.format(myNumber)));
} catch (ParseException e) {}
}
}
import java.util.regex;
public static void isDigital(String data)
{
Pattern ptn=Pattern.compile("^(-|\\+)?\\d*$");
Matcher mat=ptn.matcher(data);
System.out.println(data+" is digitial ?: "+mat.matches());
}不是数字就是取反