package com.baomidou.mybatisplus.toolkit;
/**
* <p>
* StringEscape ，数据库字符串转义
* </p>
*
* @author Caratacus
* @Date 2016-10-16
*/
public class StringEscape {
/**
* 字符串是否需要转义
*
* @param str
* @param len
* @return
*/
private static boolean isEscapeNeededForString(String str, int len) {
boolean needsHexEscape = false;
for (int i = 0; i < len; ++i) {
char c = str.charAt(i);
switch (c) {
case 0: /* Must be escaped for 'mysql' */
needsHexEscape = true;
break;
case '\n': /* Must be escaped for logs */
needsHexEscape = true;
break;
case '\r':
needsHexEscape = true;
break;
case '\\':
needsHexEscape = true;
break;
case '\'':
needsHexEscape = true;
break;
case '"': /* Better safe than sorry */
needsHexEscape = true;
break;
case '\032': /* This gives problems on Win32 */
needsHexEscape = true;
break;
}
if (needsHexEscape) {
break; // no need to scan more
}
}
return needsHexEscape;
}
/**
* 转义字符串
*
* @param escapeStr
* @return
*/
public static String escapeString(String escapeStr) {
if (escapeStr.matches("\'(.+)\'")) {
escapeStr = escapeStr.substring(1, escapeStr.length() - 1);
}
String parameterAsString = escapeStr;
int stringLength = escapeStr.length();
if (isEscapeNeededForString(escapeStr, stringLength)) {
StringBuilder buf = new StringBuilder((int) (escapeStr.length() * 1.1));
//
// Note: buf.append(char) is _faster_ than appending in blocks,
// because the block append requires a System.arraycopy().... go
// figure...
//
for (int i = 0; i < stringLength; ++i) {
char c = escapeStr.charAt(i);
switch (c) {
case 0: /* Must be escaped for 'mysql' */
buf.append('\\');
buf.append('0');
break;
case '\n': /* Must be escaped for logs */
buf.append('\\');
buf.append('n');
break;
case '\r':
buf.append('\\');
buf.append('r');
break;
case '\\':
buf.append('\\');
buf.append('\\');
break;
case '\'':
buf.append('\\');
buf.append('\'');
break;
case '"': /* Better safe than sorry */
buf.append('\\');
buf.append('"');
break;
case '\032': /* This gives problems on Win32 */
buf.append('\\');
buf.append('Z');
break;
default:
buf.append(c);
}
}
parameterAsString = buf.toString();
}
return "\'" + parameterAsString + "\'";
}
}