test



package com.ebay.test;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public
class StringUtil {

public
static
void main(String[] args) {

try {

int result = StringUtil.stringToInt("-1000.01");

System.out.println(result);

} catch (NumFmtException e) {

e.printStackTrace();
} catch (NumExcessException e) {

e.printStackTrace();
}
}

public
static
int stringToInt(String str)
throws NumFmtException, NumExcessException {

int result = 0;

//preProcess string

String tmpStr = preProcess(str);
if (tmpStr.equals(""))
{

return 0;

}
if(isLegalInt(tmpStr)) {

System.out.println("is
legalInt");

result = process(tmpStr);
} else {

throw
new NumFmtException("string
must match ^-?([1-9]\\d*\\.\\d*|0\\.\\d*[1-9]\\d*|0?\\.0+|0|1-9]\\d*)$");

}

return result;

}

/**

* check if the string match regex

*
@param str

*
@return

*/

private
static
boolean isLegalInt(String str) {

Pattern p = Pattern
.compile("^-?([1-9]\\d*\\.\\d*|0\\.\\d*[1-9]\\d*|0?\\.0+|0|[1-9]\\d*)$");

Matcher m = p.matcher(str);
if (m.matches()) {

return
true;

} else {

return
false;

}
}

/**

* trim the string
*
*
@param str

*
@return

*/

private
static String preProcess(String str) {

if(str ==
null) {

return
"";

}
return str.trim();

}

private
static
int process(String str)
throws NumExcessException {

//remove '.' and negative sign

boolean isNegative =
false;

int result = 0;

String tmpStr = "";

if(str.contains("."))
{

tmpStr = str.substring(0, str.indexOf("."));

}
if (tmpStr.startsWith("-"))
{

isNegative = true;

tmpStr = tmpStr.substring(1, tmpStr.length());
}

//convert to long first

char[] chs = tmpStr.toCharArray();

long l = 0l;

for (int
i = chs.length-1, j =0; i >= 0; i--, j++) {

l += (chs[i]-'0') * Math.pow(10, j);

}

//check value range

if (l>Integer.MAX_VALUE)
{

throw
new NumExcessException("string
is excess integer max value");

}
result = (int)l;

if (isNegative) {

result *= -1;
}
return result;

}

/**

* validate the string
*
*
@param str

*
@return

*/

private
static
boolean
validate(String str) {

return
true;

}

static
class
NumFmtException extends Exception {

public NumFmtException(String message) {

super(message);

}
}

static
class
NumExcessException extends Exception {

public NumExcessException(String message) {

super(message);

}
}
}