豬

01 public class Test {
02 /**
03 * Simplest in Java 1.5, using the replace method, which
04 * takes CharSequence objects.
05 */
06 public static String replace15(
07     String aInput, String aOldPattern, String aNewPattern){
08     return aInput.replace(aOldPattern, aNewPattern);
09 }
10 /**
11 * Not quite as simple in Java 1.4. The replaceAll method works,
12 * but requires more care, since it uses regular expressions, which
13 * may contain special characters.
14 */
15 public static String replace14(
16     String aInput, String aOldPattern, String aNewPattern){
17     /*
18     * The replaceAll method is a bit dangerous to use.
19     * The aOldPattern is converted into a regular expression.
20     * Thus, if aOldPattern may contain characters which have
21     * special meaning to regular expressions, then they must
22     * be 'escaped' before being passed to replaceAll. It is
23     * easy to forget to do this.
24     *
25     * In addition, aNewPattern treats '$' as special characters
26     * as well: they refer to 'back references'.
27     */
28     return aInput.replaceAll(aOldPattern, aNewPattern);
29     /*
30     Here is an alternative implementation using Pattern and Matcher,
31     which is preferred when the same pattern is used repeatedly
32     final Pattern pattern = Pattern.compile( aOldPattern );
33     final Matcher matcher = pattern.matcher( aInput );
34     return matcher.replaceAll( aNewPattern );
35     */
36 }
37 /**
38 * If Java 1.4 is unavailable, the following technique may be used.
39 *
40 * @param aInput is the original String which may contain substring aOldPattern
41 * @param aOldPattern is the non-empty substring which is to be replaced
42 * @param aNewPattern is the replacement for aOldPattern
43 */
44 public static String replaceOld(
45     final String aInput,
46     final String aOldPattern,
47     final String aNewPattern){
48      if ( aOldPattern.equals("") ) {
49         throw new IllegalArgumentException("Old pattern must have content.");
50      }
51      final StringBuffer result = new StringBuffer();
52      //startIdx and idxOld delimit various chunks of aInput; these
53      //chunks always end where aOldPattern begins
54      int startIdx = 0;
55      int idxOld = 0;
56      while ((idxOld = aInput.indexOf(aOldPattern, startIdx)) >= 0) {
57        //grab a part of aInput which does not include aOldPattern
58        result.append( aInput.substring(startIdx, idxOld) );
59        //add aNewPattern to take place of aOldPattern
60        result.append( aNewPattern );
61        //reset the startIdx to just after the current match, to see
62        //if there are any further matches
63        startIdx = idxOld + aOldPattern.length();
64      }
65      //the final chunk will go to the end of aInput
66      result.append( aInput.substring(startIdx) );
67      return result.toString();
68 }
69 /** Example: update an ip address appearing in a link. */
70 public static void main (String[] aArguments) {
71     String OLD_IP = "insert into LOAD_POLIINFO (IDCARD,POLISTAT,JOINDATE,LOADNO) values ('110102197906300508','13',to_date('null ','yyyy-mm-dd'),70990)";
72 log(replaceOld(OLD_IP,"to_date('null ','yyyy-mm-dd')","null"));
73 }
74 private static void log(String aMessage){
75     System.out.println(aMessage);
76 }
77 }