stringutil.java

Struts入门的一个好例子 Struts入门的一个好例子

package bily.notebook.util;

public class StringUtil {
	
	/**
	 * 判断字符串为空，为空则返回true
	 * @param str
	 * @return
	 */
	public static boolean isEmpty(String str) {
		return (str == null || "".equals(str.trim()));
	}
	
	/**
	 * 判断字符串不空，不空则返回true
	 * @param str
	 * @return
	 */
	public static boolean isNotEmpty(String str) {
		return !isEmpty(str);
	}
	
	/**
	 * 判断字符串是否为数字格式
	 * @param str
	 * @return
	 */
	public static boolean isInteger(String str) {
		boolean yes = false;
		try {
			Long.parseLong(str);
			yes = true;
		} catch (Exception e) {
		}		
		return yes;
	}
	
	public static String replaceSqlLike(String strin, char chEscape) {
		if (isEmpty(strin)) return "";
        String strEscape = String.valueOf(chEscape);
        strin = replace(strin, strEscape, strEscape + strEscape);
        strin = replace(strin, "%", strEscape + "%");
        strin = replace(strin, "_", strEscape + "_");
        strin = replace(strin, "'", "''");
        return strin;
    }
	
	public static String replace(String str1, String str2, String str3) {
		if (isEmpty(str1)) return "";
		String str = str1.replaceAll(str2, str3);
		return str;
	}
	
	public static String emptyToNull(String str) {
		return isNotEmpty(str) ? str : null;
	}
	
	public static String emptyToChar(String str, String rep) {
		return isNotEmpty(str) ? str : rep;
	}
	
	public static String nullToEmpty(String str) {
		return isNotEmpty(str) ? str : "";
	}
	
	public static String lpad(int num, int length, char c) {
		String str = String.valueOf(num);
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < length - str.length(); i++ ) sb.append(c);
		sb.append(str);
		return sb.toString();
	}
}