直接上代码，经过验证。
package javaTest;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class test {
/***
*
* @param args
* java判断字符是否是全部由数字，小写字母，大写字母，特殊符号组成
* 正则表达式判断
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String str = "aksjfjJAJIFJSL12455432^&^&(";
String str1 = "abcdfjijgiaj";
String str2 = "JAOGVNDIJEIO";
String str3 = "12345465870";
String str4 = "@#$^^%^&*(";
Pattern pattern1 = pile("[a-z]*");
Pattern pattern2 = pile("[A-Z]*");
Pattern pattern3 = pile("[0-9]*");
Pattern pattern4 = pile("\\p{Punct}+");
Matcher matcher1 = pattern1.matcher(str1);
Matcher matcher2 = pattern2.matcher(str2);
Matcher matcher3 = pattern3.matcher(str3);
Matcher matcher4 = pattern4.matcher(str4);
if (matcher1.matches()) {
System.out.println("全是小写字母");
}
else {
System.out.println("不全是小写字母");
}
if (matcher2.matches()) {
System.out.println("全是大写字母");
}
else {
System.out.println("不全是大写字母");
}
if (matcher3.matches()) {
System.out.println("全是数字");
}
else {
System.out.println("不全是数字");
}
if (matcher4.matches()) {
System.out.println("全是特殊符号");
}
else {
System.out.println("不全是特殊符号");
}
//判断字符串是否全部由数字组成，java自带方法判断
boolean flag = true;
for (int i = str3.length()-1; i >= 0; i--) {
if (!Character.isDigit(str3.charAt(i))) {
flag = false;
}
}
if (flag) {
System.out.println(str3 + "全部是数字");
}
}
}
转自：/zgcy123456/article/details/9428933
