public class StringUtil {
/**
* 例如：StringUtil.substring("richer",4) 得到的结果为：rich
* <p>
* 得到字符串指定长度字符
*
* @param str
* 字符串
* @param len：
* 要得到的字符个数
* @return 截取后得到的字符
*/
public static String substring(String str, int len)
{
if(str==null || len<1){
return null;
}else if(str.length()<len){
return str;
}else{
return str.substring(0,len);
}
}
/**
* 根据时间用于生成自定义文件
* 例如：StringUtil.formatDateHtml("2006-10-10 23:22:09",null)结果为：20061010232209
* StringUtil.formatDateHtml("2006-10-10 23:22:09",".html")结果为：20061010232209.html
* <p>
* 用于生成随机的HTML文件
*
* @param str
* 日期字符串
* @param s
* 文件的后缀名,注意前面加“.”
*
* @return 返回格式化完成后的字符串
*/
public static String formatDateHtml(String str,String s)
{
StringBuffer re=new StringBuffer();
java.util.StringTokenizer analysis=new java.util.StringTokenizer(str,"- :");
while(analysis.hasMoreTokens())
{
re.append(analysis.nextToken());
}
if(!(s==null)){
re.append(s);
}
return re.toString();
}
/**
* <p>
* 把字符打散转换成UTF-8的格式，用于解决网页上汉字乱码
*
* @param str
* 字符串
* @return 截取后得到的字符
*/
public static String getEncodeStr(String str) {
String strUtf8 = null;
try {
strUtf8 = new String(str.getBytes("ISO-8859-1"),"utf-8");
} catch (UnsupportedEncodingException e) {
}
return strUtf8;
}
/**
* <p>
* 把字符打散转换成自定义的格式，用于解决网页上汉字乱码
*
* @param str
* 字符串
* @param from
* 字符集名
* @param to
* 字符集名
* @return 截取后得到的字符
*/
public static String getEncodeStr(String str,String from, String to) {
String strUtf8 = null;
try {
strUtf8 = new String(str.getBytes(from),to);
} catch (UnsupportedEncodingException e) {
}
return strUtf8;
}
/**
* <p>
* 类似ORACLE中的nvl函数，如果str为空，就把d的值赋给str
* @param str
* 字符串
* @param d
* 字符串
* @return
*/
public static String nvl(String str, String d){
return str==null? d:str;
}
/**
* <p>
* 检查字符串是否为空或空白
* @param param
* 字符串
* @return
*/
public static boolean isNullOrBlank(String param) {
return (param == null || param.trim().equals("")) ? true : false;
}
/**
* 把String转换成double，JDK自带的有时候转换比较麻烦
*/
public static double parseDouble(String param) {
double d = 0;
try {
d = Double.parseDouble(param);
} catch (Exception e) {
//
}
return d;
}
/**
* 把String转换成float，JDK自带的有时候转换比较麻烦
*/
public static float parseFloat(String param) {
float f = 0f;
try {
f = Float.parseFloat(param);
} catch (Exception e) {
//
}
return f;
}
/**
* 把String转换成int，JDK自带的有时候转换比较麻烦
*/
public static int parseInt(String param) {
int i = 0;
try {
i = Integer.parseInt(param);
} catch (Exception e) {
i = (int) parseFloat(param);
}
return i;
}
/**
* 把String转换成long，JDK自带的有时候转换比较麻烦
*/
public static long parseLong(String param) {
long l = 0;
try {
l = Long.parseLong(param);
} catch (Exception e) {
l = (long) parseDouble(param);
}
return l;
}
private static char[] numbersAndLetters = ("0123456789abcdefghijklmnopqrstuvwxyz"
+ "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
private static Random randGen = new Random();
/**
* 例如：StringUtil.randomStr(5) 生成：Ja251
* <p>
* 生成一个指定长度的随机字符串，使用于做文件名
* @param length
* 生成的长度
* @return
*/
public static final String randomStr(int length) {
if (length < 1) {
return null;
}
char[] randBuffer = new char[length];
for (int i = 0; i < randBuffer.length; i++) {
randBuffer[i] = numbersAndLetters[randGen.nextInt(71)];
}
return new String(randBuffer);
}
/**
* 例如：StringUtil.randomNum(5) 生成：06512
* <p>
* 生成一个指定长度的随机数，使用于做文件名
* @param length
* 生成的长度
* @return
*/
public static final String randomNum(int length) {
if (length < 1) {
return null;
}
StringBuffer randBuffer = new StringBuffer();
for (int i = 0; i < length; i++) {
randBuffer.append(Integer.toString(randGen.nextInt(9)));
}
return randBuffer.toString();
}
/**
* 将半角的符号转换成全角符号
*/
public static String changeToFull(String str) {
String source = "1234567890!@#$%^&*()abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_=+\\|[];:'\",<.>/?";
String[] decode = { "１", "２", "３", "４", "５", "６", "７", "８", "９", "０",
"！", "＠", "＃", "＄", "％", "︿", "＆", "＊", "（", "）", "ａ", "ｂ",
"ｃ", "ｄ", "ｅ", "ｆ", "ｇ", "ｈ", "ｉ", "ｊ", "ｋ", "ｌ", "ｍ", "ｎ",
"ｏ", "ｐ", "ｑ", "ｒ", "ｓ", "ｔ", "ｕ", "ｖ", "ｗ", "ｘ", "ｙ", "ｚ",
"Ａ", "Ｂ", "Ｃ", "Ｄ", "Ｅ", "Ｆ", "Ｇ", "Ｈ", "Ｉ", "Ｊ", "Ｋ", "Ｌ",
"Ｍ", "Ｎ", "Ｏ", "Ｐ", "Ｑ", "Ｒ", "Ｓ", "Ｔ", "Ｕ", "Ｖ", "Ｗ", "Ｘ",
"Ｙ", "Ｚ", "－", "＿", "＝", "＋", "＼", "｜", "【", "】", "；", "：",
"'", "\"", "，", "〈", "。", "〉", "／", "？" };
String result = "";
for (int i = 0; i < str.length(); i++) {
int pos = source.indexOf(str.charAt(i));
if (pos != -1) {
result += decode[pos];
} else {
result += str.charAt(i);
}
}
return result;
}
private final static String[] hexDigits = {
"0", "1", "2", "3", "4", "5", "6", "7",
"8", "9", "a", "b", "c", "d", "e", "f"};
private static String byteArrayToHexString(byte[] b) {
StringBuffer resultSb = new StringBuffer();
for (int i = 0; i < b.length; i++) {
resultSb.append(byteToHexString(b[i]));
}
return resultSb.toString();
}
private static String byteToHexString(byte b) {
int n = b;
if (n < 0)
n = 256 + n;
int d1 = n / 16;
int d2 = n % 16;
return hexDigits[d1] + hexDigits[d2];
}
/**
* 例如：StringUtil.MD5("richer") 生成：43091a5955ffeb31300b99c81bf90094
* <p>
* 把字符串转换成MD5，使用于加密
* @param origin
* 字符串
* @return
*/
public static String md5(String origin) {
String resultString = null;
try {
resultString = new String(origin);
MessageDigest md = MessageDigest.getInstance("MD5");
resultString = byteArrayToHexString(md.digest(resultString
.getBytes()));
} catch (Exception ex) {
}
return resultString;
}
private static final char[] zeroArray = "0000000000000000".toCharArray();
/**
* 例如：StringUtil.zeroPadStr("1234",10) 生成：0000001234
* <p>
* 把字符串转换成指定长度，不够在前面补0，适用于数据库ID补位
* @return
*/
public static final String zeroPadStr(String string, int length) {
if (string == null || string.length() > length) {
return string;
}
StringBuffer buf = new StringBuffer(length);
buf.append(zeroArray, 0, length - string.length()).append(string);
return buf.toString();
}
private static final char[] GT_ENCODE = ">".toCharArray();
private static final char[] LT_ENCODE = "<".toCharArray();
/**
* 例如：StringUtil.escapeHTMLTags("<P>richer</P>") 生成：<P>richer</P>
* <p>
* 把HTML中的字符进行转换，适用于网页
* @param in
* 字符串
* @return
*/
public static final String escapeHTMLTags(String in) {
if (in == null) {
return null;
}
char ch;
int i = 0;
int last = 0;
char[] input = in.toCharArray();
int len = input.length;
StringBuffer out = new StringBuffer((int) (len * 1.3));
for (; i < len; i++) {
ch = input[i];
if (ch > '>') {
continue;
} else if (ch == '<') {
if (i > last) {
out.append(input, last, i - last);
}
last = i + 1;
out.append(LT_ENCODE);
} else if (ch == '>') {
if (i > last) {
out.append(input, last, i - last);
}
last = i + 1;
out.append(GT_ENCODE);
}
}
if (last == 0) {
return in;
}
if (i > last) {
out.append(input, last, i - last);
}
return out.toString();
}
private static final String cvt =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "abcdefghijklmnopqrstuvwxyz"
+ "0123456789+/";
private static final int fillchar = '=';
private static String encodeBase64(byte[] data) {
int c;
int len = data.length;
StringBuffer ret = new StringBuffer(((len / 3) + 1) * 4);
for (int i = 0; i < len; ++i) {
c = (data[i] >> 2) & 0x3f;
ret.append(cvt.charAt(c));
c = (data[i] << 4) & 0x3f;
if (++i < len)
c |= (data[i] >> 4) & 0x0f;
ret.append(cvt.charAt(c));
if (i < len) {
c = (data[i] << 2) & 0x3f;
if (++i < len)
c |= (data[i] >> 6) & 0x03;
ret.append(cvt.charAt(c));
} else {
++i;
ret.append((char) fillchar);
}
if (i < len) {
c = data[i] & 0x3f;
ret.append(cvt.charAt(c));
} else {
ret.append((char) fillchar);
}
}
return ret.toString();
}
/**
* 把一个字符串转换成64位编码
*
* @param data
* 字符
* @return
*/
public static String encodeBase64(String data) {
return encodeBase64(data.getBytes());
}
}
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