处理输入框中输入非法字符的办法，将输入的非法字符转化成合法字符。

（原创）转贴请标明出处
/**
* 将输入字符串中的"/"转化为"//"
* 将单引号"'"转化为双引号"''"
* 返回类型：String
*/
public static String escapeSQLTags(String input) {
if (input != null) {
// input = replaceString(input, "//", "////");
input = replaceString(input, "/'", "/'/'");
}
return input;
}
/**
* 将输入的字符串中的"<" ">" "&" """
* 转化为Html显示的转义字符
* 返回类型：String
*/
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();
}

/**
* 将maiString中的所有oldString替换成newString
* 返回类型：String
*/
public static String replaceString(
String mainString,
String oldString,
String newString) {
if (mainString == null) {
return null;
}
if (oldString == null || oldString.length() == 0) {
return mainString;
}
if (newString == null) {
newString = "";
}
int i = mainString.lastIndexOf(oldString);
if (i < 0)
return mainString;
StringBuffer mainSb = new StringBuffer(mainString);
while (i >= 0) {
mainSb.replace(i, i + oldString.length(), newString);
i = mainString.lastIndexOf(oldString, i - 1);
}
return mainSb.toString();
}