java String工具类

package util;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Random;

/**
* 字符串处理相关工具类
*
* @author
* @date
* @version 1.0
*/
public class StringUtil {

/**
* 判断字符串是否为空或null，为空返回true
*
* @param str
*            待判定字符串
* @return 是否为空或null
*/
public static boolean isEmpty(String str) {
return (str == null || "".equals(str.trim()));
}

/**
* 对象转为string格式，为空时，转为默认带入字符串
*
* @param obj
*            待转对象
* @param defaultStr
*            默认字符串
* @return 字符串
*/
public static String objToString(Object obj, String defaultStr) {
if (obj == null || obj.toString().equals("")) {
return defaultStr;
} else {
return obj.toString();
}
}

/**
* 判断字符串长度是否合法
*
* @param instr
*            输入字符串
* @param minLength
*            最小长度
* @param maxLength
*            最大长度
* @return true=合法
*/
public static boolean chackStringLength(String instr, int minLength, int maxLength) {
return !(instr.length() < minLength || instr.length() > maxLength);
}

/**
* 判断字符串是否全是数字
*
* @param str
*            输入字符串
* @return true=全是数字
*/
public static boolean isNum(String str) {
if (null == str) {
return false;
}
return str.matches("\\d+");
}

/**
* 字符串长度处理，过长切除，不足补空格.
*
* @param str
*            传入字符串
* @param length
*            传入指定长度(字节数)
* @param defaultStr
*            默认字符
* @param isRight
*            是否右补齐
* @return 返回指定长度的字符串
*/
public static String supplyString(String str, int length, String defaultStr, boolean isRight) {
if (str != null) {
int len = str.length();
if (len < length) {
if (isRight) {
for (int i = 0; i < (length - len); i++) {
str = str + defaultStr;
}
} else {
for (int i = 0; i < (length - len); i++) {
str = defaultStr + str;
}
}
} else {
str = str.substring(0, length);
}
} else {// 空字符串
if (isRight) {
for (int i = 0; i < length; i++) {
str = str + defaultStr;
}
} else {
for (int i = 0; i < length; i++) {
str = defaultStr + str;
}
}
}
return str;
}

/**
* 字符串倒转
*
* @param str
*            输入字符串
* @return 倒转后字符串
*/
public static String reverseStr(String str) {
StringBuilder strbuff = new StringBuilder();
for (int i = str.length() - 1; i >= 0; i--) {
strbuff.append(str.charAt(i));
}
return strbuff.toString();
}

/**
* 生成随机几位数字
*
* @param k
*            生成位数
* @return
*/
public static String createRand(int k) {
Random random = new Random();
String sRand = "";
for (int i = 0; i < k; i++) {
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
}
return sRand;
}

/**
* 判断字符串起止时间格式
*
* @param time
*            如：12002400
* @return
*/
public static boolean checkTime(String time) throws Exception {
boolean result = true;
// 按逗号截取
String[] sptime = time.trim().split(",");
String lastsp = time.substring(time.length() - 1, time.length());
String firstsp = time.substring(0, 1);
for (int i = 0; i < sptime.length; i++) {
// 判断首字符是否为空
if (StringUtil.isEmpty(firstsp)) {
result = false;
break;
}
// 判断最后个时间串是否为,号
if (lastsp.equals(",")) {
result = false;
break;
}
// 判断是时间串否为数字
if (StringUtil.isNum(sptime[i]) && sptime[i].length() == {
String gettime = sptime[i];
String starttime = gettime.substring(0, 4);
String endtime = gettime.substring(4,;
// 判断时间格式是否属于24小时内
if (Integer.parseInt(starttime) > 2400 || Integer.valueOf(endtime) > 2400) {
result = false;
break;
}
// 判断起始时间是否大于截止时间
if (Integer.valueOf(starttime) >= Integer.valueOf(endtime)) {
result = false;
break;
}
} else {
result = false;
break;
}
}
return result;
}

/* String类型到Date类型转化 */

public static java.util.Date StringToDate(String strDate, int type) {
java.util.Date result = null;
String format = "yyyy-MM-dd";
if (type == 0) {
format = "yyyy-MM-dd";
}
if (type == 1) {
format = "yyyy/MM/dd";
} else if (type == 2) {
format = "yyyyMMdd";
} else if (type == 21) {
format = "yyyyMM";
} else if (type == 3) {
format = "MM/dd/yy";
} else if (type == 4) {
format = "yyyy-MM-dd HH:mm:ss";
} else if (type == 5) {
format = "yyyyMMddHHmm";
}
SimpleDateFormat formatter = new SimpleDateFormat(format);
if (strDate != null && !strDate.equals("")) {
try {
result = formatter.parse(strDate);
} catch (ParseException ex) {
result = null;
}
}
return result;
}

/* Date类型转化到String类型 */
public static String DateToString(java.util.Date date, int type) {
String result = null;
String format = "yyyy-MM-dd";
if (type == 0) {
format = "yyyy-MM-dd";
}
if (type == 1) {
format = "yyyy/MM/dd";
} else if (type == 2) {
format = "yyyyMMdd";
} else if (type == 21) {
format = "yyyyMM";
} else if (type == 3) {
format = "MM/dd/yy";
} else if (type == 4) {
format = "yyyy-MM-dd HH:mm:ss";
} else if (type == 5) {
format = "yyyyMMddHHmmss";
}
SimpleDateFormat formatter = new SimpleDateFormat(format);
if (date != null) {
result = formatter.format(date);
} else {
result = "";
}
return result;
}

/**
* 判断是否为整数
*
* @param s
* @return
*/
public static boolean isNumeric(String s) {
if ((s != null) && (s != ""))
return s.matches("^[0-9]*$");
else
return false;
}

/**
* 判断字符串是否由字母和数字和|号组成
*
* @param str 输入字符串
* @return
*/
public static boolean isNumOrLetter(String str) {
if (null == str) {
return false;
}
return str.matches("^[0-9a-zA-Z|]+$");
}
}