Java SQL Unescape unescapeSQLString(String b)

Description

unescape SQL String

License

Apache License

Declaration

@SuppressWarnings("nls")
    public static String unescapeSQLString(String b) 

Method Source Code

//package com.java2s;
/**//w  ww  .j  av  a  2 s  .c o m
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class Main {
    private static final int[] multiplier = new int[] { 1000, 100, 10, 1 };

    @SuppressWarnings("nls")
    public static String unescapeSQLString(String b) {
        Character enclosure = null;

        // Some of the strings can be passed in as unicode. For example, the
        // delimiter can be passed in as \002 - So, we first check if the
        // string is a unicode number, else go back to the old behavior
        StringBuilder sb = new StringBuilder(b.length());
        for (int i = 0; i < b.length(); i++) {

            char currentChar = b.charAt(i);
            if (enclosure == null) {
                if (currentChar == '\'' || b.charAt(i) == '\"') {
                    enclosure = currentChar;
                }
                // ignore all other chars outside the enclosure
                continue;
            }

            if (enclosure.equals(currentChar)) {
                enclosure = null;
                continue;
            }

            if (currentChar == '\\' && (i + 6 < b.length()) && b.charAt(i + 1) == 'u') {
                int code = 0;
                int base = i + 2;
                for (int j = 0; j < 4; j++) {
                    int digit = Character.digit(b.charAt(j + base), 16);
                    code += digit * multiplier[j];
                }
                sb.append((char) code);
                i += 5;
                continue;
            }

            if (currentChar == '\\' && (i + 4 < b.length())) {
                char i1 = b.charAt(i + 1);
                char i2 = b.charAt(i + 2);
                char i3 = b.charAt(i + 3);
                if ((i1 >= '0' && i1 <= '1') && (i2 >= '0' && i2 <= '7') && (i3 >= '0' && i3 <= '7')) {
                    byte bVal = (byte) ((i3 - '0') + ((i2 - '0') * 8) + ((i1 - '0') * 8 * 8));
                    byte[] bValArr = new byte[1];
                    bValArr[0] = bVal;
                    String tmp = new String(bValArr);
                    sb.append(tmp);
                    i += 3;
                    continue;
                }
            }

            if (currentChar == '\\' && (i + 2 < b.length())) {
                char n = b.charAt(i + 1);
                switch (n) {
                case '0':
                    sb.append("\0");
                    break;
                case '\'':
                    sb.append("'");
                    break;
                case '"':
                    sb.append("\"");
                    break;
                case 'b':
                    sb.append("\b");
                    break;
                case 'n':
                    sb.append("\n");
                    break;
                case 'r':
                    sb.append("\r");
                    break;
                case 't':
                    sb.append("\t");
                    break;
                case 'Z':
                    sb.append("\u001A");
                    break;
                case '\\':
                    sb.append("\\");
                    break;
                // The following 2 lines are exactly what MySQL does TODO: why do we do this?
                case '%':
                    sb.append("\\%");
                    break;
                case '_':
                    sb.append("\\_");
                    break;
                default:
                    sb.append(n);
                }
                i++;
            } else {
                sb.append(currentChar);
            }
        }
        return sb.toString();
    }
}

Related

1. unescapeMySQLString(String s)
2. unescapeSQL(String input)
3. unescapeSQLString(String b)
4. unescapeSqlString(String input)
5. unescapeSQLString(String str, String delim)