java中判断字符串是不是为纯数字

Posted 2023-03-23

方法一：利用正则表达式public class Testone public static void main(String[] args)String str="123456";boolean result=str.matches("[0-9]+");if (result == true) System.out.println("该字符串是纯数字");elseSystem.out.println("该字符串不是纯数字");方法二：利用Pattern.import java.util.regex.Matcher;import java.util.regex.Pattern;public class Testone public static void main(String[] args)String str="123456";Pattern pattern = Pattern.compile("[0-9]1,");Matcher matcher = pattern.matcher((CharSequence)str);boolean result=matcher.matches();System.out.println("该字符串是纯数字");elseSystem.out.println("该字符串不是纯数字"); 参考技术A 方法一：利用正则表达式
public class Testone
public static void main(String[] args)
String str="123456";
boolean result=str.matches("[0-9]+");
if (result == true)
System.out.println("该字符串是纯数字");elseSystem.out.println("该字符串不是纯数字");方法二：利用Pattern.
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Testone
public static void main(String[] args)
String str="123456";
Pattern pattern = Pattern.compile("[0-9]1,");
Matcher matcher = pattern.matcher((CharSequence)str);
boolean result=matcher.matches();
System.out.println("该字符串是纯数字");elseSystem.out.println("该字符串不是纯数字"); 参考技术B java中判断字符串是否为纯数字的方法如下：
方法一：Pattern语句
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Testone
public static void main(String[ ] args)
String str="123456";
Pattern pattern = Pattern.compile("[0-9]1,");
Matcher matcher = pattern.matcher((CharSequence)str);
boolean result=matcher.matches();
if (result == true)
System.out.println("该字符串是纯数字");

else
System.out.println("该字符串不是纯数字");



方法二：正则表达式
<span style="white-space:pre"></span>
public static boolean isNumber(String str)
String reg = "^[0-9]+(.[0-9]+)?$";
return str.matches(reg);
参考技术C //方法一：用JAVA自带的函数
public static boolean isNumeric(String str)
for (int i = str.length();--i>=0;)

if (!Character.isDigit(str.charAt(i)))

return false;6


return true;


/*方法二：推荐，速度最快
* 判断是否为整数
* @param str 传入的字符串
* @return 是整数返回true,否则返回false
*/
public static boolean isInteger(String str)
Pattern pattern = Pattern.compile("^[-\\+]?[\\d]*$");
return pattern.matcher(str).matches();

//方法三：public static boolean isNumeric(String str)
Pattern pattern = Pattern.compile("[0-9]*"); return pattern.matcher(str).matches();


//方法四：public final static boolean isNumeric(String s) if (s != null && !"".equals(s.trim())) return s.matches("^[0-9]*$"); else
return false;

//方法五：用ascii码 public static boolean isNumeric(String str) for(int i=str.length();--i>=0;) int chr=str.charAt(i); if(chr<48 || chr>57) return false;
return true;
参考技术D 方法一：利用正则表达式
public class Testone
public static void main(String[] args)
String str="123456";
boolean result=str.matches("[0-9]+");
if (result == true)
System.out.println("该字符串是纯数字");elseSystem.out.println("该字符串不是纯数字");方法二：利用Pattern.
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Testone
public static void main(String[] args)
String str="123456";
Pattern pattern = Pattern.compile("[0-9]1,");
Matcher matcher = pattern.matcher((CharSequence)str);
boolean result=matcher.matches();

java验证字符串是不是为数字

参考技术A java中判断字符串是否为纯数字的方法如下：
方法一：Pattern语句
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Testone
public static void main(String[ ] args)
String str="123456";
Pattern pattern = Pattern.compile("[0-9]1,");
Matcher matcher = pattern.matcher((CharSequence)str);
boolean result=matcher.matches();
if (result == true)
System.out.println("该字符串是纯数字");

else
System.out.println("该字符串不是纯数字");



方法二：正则表达式

public static boolean isNumber(String str)
String reg = "^[0-9]+(.[0-9]+)?$";
return str.matches(reg);