随机字符串生成器，字符集为ascii可打印字符

RandomPrintableStringGenerator.java

package test;

import java.util.Random;

/**
 * 生成指定长度的随机串，字符范围仅限于ascii可打印字符: https://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters
 * @author pf-miles Nov 16, 2015 3:18:13 PM
 */
public abstract class RandomPrintableStringGenerator {
    private static final Random r  = new Random();
    // 33 ~ 126是ascii可见字符
    private static final char[] cs = new char[126 - 32];
    static {
        for (int i = 0; i < cs.length; i++) {
            cs[i] = (char) (i + 33);
        }
    }

    /**
     * 生成指定长度的随机串， 字符范围为ascii可打印字符
     * @param length
     */
    public static String randString(int length) {
        if (length < 1 || length > 128)
            throw new IllegalArgumentException("Illegal random string length.");
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < length; i++)
            sb.append(cs[r.nextInt(cs.length)]);
        return sb.toString();
    }

}