logreader.html

用JAVA编写的,在做实验的时候留下来的,本来想删的,但是传上来,大家分享吧

<a name="439" href="#439">439</a>             <strong>return</strong> <strong>null</strong>;
<a name="440" href="#440">440</a>         }
<a name="441" href="#441">441</a>     }
<a name="442" href="#442">442</a> 
<a name="443" href="#443">443</a>     <em>/**<em>*</em></em>
<a name="444" href="#444">444</a> <em>     * Returns all lines in a log/file matching a given regular expression.  </em>
<a name="445" href="#445">445</a> <em>     * Possible to get lines immediately following the matched line.  Also </em>
<a name="446" href="#446">446</a> <em>     * possible to have each line prepended by it's line number.</em>
<a name="447" href="#447">447</a> <em>     *</em>
<a name="448" href="#448">448</a> <em>     * @param reader The reader of the log/file</em>
<a name="449" href="#449">449</a> <em>     * @param regExpr The regular expression that is to be used</em>
<a name="450" href="#450">450</a> <em>     * @param addLines How many lines (in addition to the matched line) to add. </em>
<a name="451" href="#451">451</a> <em>     *                 A value less then 1 will mean that only the matched line </em>
<a name="452" href="#452">452</a> <em>     *                 will be included. If another matched line is hit before </em>
<a name="453" href="#453">453</a> <em>     *                 we reach this limit it will be included and this counter</em>
<a name="454" href="#454">454</a> <em>     *                 effectively reset for it.</em>
<a name="455" href="#455">455</a> <em>     * @param prependLineNumbers If true, then each line will be prepended by </em>
<a name="456" href="#456">456</a> <em>     *                           it's line number in the file.</em>
<a name="457" href="#457">457</a> <em>     * @param skipFirstMatches The first number of matches up to this value will</em>
<a name="458" href="#458">458</a> <em>     *                         be skipped over.</em>
<a name="459" href="#459">459</a> <em>     * @param numberOfMatches Once past matches that are to be skipped this many</em>
<a name="460" href="#460">460</a> <em>     *                        matches will be added to the return value. A</em>
<a name="461" href="#461">461</a> <em>     *                        value of 0 will cause all matching lines to be</em>
<a name="462" href="#462">462</a> <em>     *                        included.</em>
<a name="463" href="#463">463</a> <em>     * @param logsize Size of the log in bytes</em>
<a name="464" href="#464">464</a> <em>     * @return An array of two strings is returned. At index 0 all lines in a</em>
<a name="465" href="#465">465</a> <em>     *         log/file matching a given regular expression is located.</em>
<a name="466" href="#466">466</a> <em>     *         At index 1 there is an informational string about how large a</em>
<a name="467" href="#467">467</a> <em>     *         segment of the file is being returned.</em>
<a name="468" href="#468">468</a> <em>     *         Null is returned if errors occur (file not found or io exception)</em>
<a name="469" href="#469">469</a> <em>     *         If a PatternSyntaxException occurs, it's error message will be</em>
<a name="470" href="#470">470</a> <em>     *         returned and the informational string will be empty (not null).</em>
<a name="471" href="#471">471</a> <em>     */</em>
<a name="472" href="#472">472</a>     <strong>public</strong> <strong>static</strong> String[] getByRegExpr(InputStreamReader reader,
<a name="473" href="#473">473</a>                                       String regExpr,
<a name="474" href="#474">474</a>                                       <strong>int</strong> addLines,
<a name="475" href="#475">475</a>                                       <strong>boolean</strong> prependLineNumbers,
<a name="476" href="#476">476</a>                                       <strong>int</strong> skipFirstMatches,
<a name="477" href="#477">477</a>                                       <strong>int</strong> numberOfMatches,
<a name="478" href="#478">478</a>                                       <strong>long</strong> logsize) {
<a name="479" href="#479">479</a>         StringBuffer ret = <strong>new</strong> StringBuffer();
<a name="480" href="#480">480</a>         String info = <span class="string">""</span>;
<a name="481" href="#481">481</a> 
<a name="482" href="#482">482</a>         <strong>try</strong>{
<a name="483" href="#483">483</a>             Pattern p = Pattern.compile(regExpr);
<a name="484" href="#484">484</a>             BufferedReader bf = <strong>new</strong> BufferedReader(reader, 8192);
<a name="485" href="#485">485</a> 
<a name="486" href="#486">486</a>             String line = <strong>null</strong>;
<a name="487" href="#487">487</a>             <strong>int</strong> i = 1;
<a name="488" href="#488">488</a>             <strong>boolean</strong> doAdd = false;
<a name="489" href="#489">489</a>             <strong>int</strong> addCount = 0;
<a name="490" href="#490">490</a>             <strong>long</strong> linesMatched = 0;
<a name="491" href="#491">491</a>             <strong>while</strong> ((line = bf.readLine()) != <strong>null</strong>) {
<a name="492" href="#492">492</a>                 <strong>if</strong>(p.matcher(line).matches()){
<a name="493" href="#493">493</a>                     <em class="comment">// Found a match</em>
<a name="494" href="#494">494</a>                     <strong>if</strong>(numberOfMatches > 0 &amp;&amp;
<a name="495" href="#495">495</a>                             linesMatched >= skipFirstMatches + numberOfMatches){
<a name="496" href="#496">496</a>                         <em class="comment">// Ok, we are done.</em>
<a name="497" href="#497">497</a>                         <strong>break</strong>;
<a name="498" href="#498">498</a>                     }
<a name="499" href="#499">499</a>                     linesMatched++;
<a name="500" href="#500">500</a>                     <strong>if</strong>(linesMatched > skipFirstMatches){
<a name="501" href="#501">501</a>                         <strong>if</strong>(prependLineNumbers){
<a name="502" href="#502">502</a>                             ret.append(i);
<a name="503" href="#503">503</a>                             ret.append(<span class="string">". "</span>);
<a name="504" href="#504">504</a>                         }
<a name="505" href="#505">505</a>                         ret.append(line);
<a name="506" href="#506">506</a>                         ret.append(<span class="string">"\n"</span>);
<a name="507" href="#507">507</a>                         doAdd = <strong>true</strong>;
<a name="508" href="#508">508</a>                         addCount = 0;
<a name="509" href="#509">509</a>                     }
<a name="510" href="#510">510</a>                 } <strong>else</strong> <strong>if</strong>(doAdd) {
<a name="511" href="#511">511</a>                     <strong>if</strong>(addCount &lt; addLines){
<a name="512" href="#512">512</a>                         <em class="comment">//Ok, still within addLines</em>
<a name="513" href="#513">513</a>                         linesMatched++;
<a name="514" href="#514">514</a>                         <strong>if</strong>(prependLineNumbers){
<a name="515" href="#515">515</a>                             ret.append(i);
<a name="516" href="#516">516</a>                             ret.append(<span class="string">". "</span>);
<a name="517" href="#517">517</a>                         }
<a name="518" href="#518">518</a>                         ret.append(line);
<a name="519" href="#519">519</a>                         ret.append(<span class="string">"\n"</span>);
<a name="520" href="#520">520</a>                     }<strong>else</strong>{
<a name="521" href="#521">521</a>                         doAdd = false;
<a name="522" href="#522">522</a>                         addCount = 0;
<a name="523" href="#523">523</a>                     }
<a name="524" href="#524">524</a>                 }
<a name="525" href="#525">525</a>                 i++;
<a name="526" href="#526">526</a>             }
<a name="527" href="#527">527</a>             info = buildDisplayingHeader(ret.length(), logsize);
<a name="528" href="#528">528</a>         }<strong>catch</strong>(FileNotFoundException e){
<a name="529" href="#529">529</a>             <strong>return</strong> <strong>null</strong>;
<a name="530" href="#530">530</a>         }<strong>catch</strong>(IOException e){
<a name="531" href="#531">531</a>             e.printStackTrace();
<a name="532" href="#532">532</a>             <strong>return</strong> <strong>null</strong>;
<a name="533" href="#533">533</a>         }<strong>catch</strong>(PatternSyntaxException e){
<a name="534" href="#534">534</a>             ret = <strong>new</strong> StringBuffer(e.getMessage());
<a name="535" href="#535">535</a>         }
<a name="536" href="#536">536</a>         String[] tmp = {ret.toString(),info};
<a name="537" href="#537">537</a>         <strong>return</strong> tmp;
<a name="538" href="#538">538</a>     }
<a name="539" href="#539">539</a> 
<a name="540" href="#540">540</a>     <em>/**<em>*</em></em>
<a name="541" href="#541">541</a> <em>     * Returns all lines in a log/file matching a given regular expression.  </em>
<a name="542" href="#542">542</a> <em>     * Possible to get lines immediately following the matched line.  Also </em>
<a name="543" href="#543">543</a> <em>     * possible to have each line prepended by it's line number.</em>
<a name="544" href="#544">544</a> <em>     *</em>
<a name="545" href="#545">545</a> <em>     * @param aFileName The filename of the log/file</em>
<a name="546" href="#546">546</a> <em>     * @param regExpr The regular expression that is to be used</em>
<a name="547" href="#547">547</a> <em>     * @param addLines Any lines following a match that &lt;b>begin&lt;/b> with this </em>
<a name="548" href="#548">548</a> <em>     *                 string will also be included. We will stop including new </em>
<a name="549" href="#549">549</a> <em>     *                 lines once we hit the first that does not match.</em>
<a name="550" href="#550">550</a> <em>     * @param prependLineNumbers If true, then each line will be prepended by </em>
<a name="551" href="#551">551</a> <em>     *                           it's line number in the file.</em>
<a name="552" href="#552">552</a> <em>     * @param skipFirstMatches The first number of matches up to this value will</em>
<a name="553" href="#553">553</a> <em>     *                         be skipped over.</em>
<a name="554" href="#554">554</a> <em>     * @param numberOfMatches Once past matches that are to be skipped this many</em>
<a name="555" href="#555">555</a> <em>     *                        matches will be added to the return value. A</em>
<a name="556" href="#556">556</a> <em>     *                        value of 0 will cause all matching lines to be</em>
<a name="557" href="#557">557</a> <em>     *                        included.</em>
<a name="558" href="#558">558</a> <em>     * @return An array of two strings is returned. At index 0 tall lines in a</em>
<a name="559" href="#559">559</a> <em>     *         log/file matching a given regular expression is located.</em>
<a name="560" href="#560">560</a> <em>     *         At index 1 there is an informational string about how large a</em>
<a name="561" href="#561">561</a> <em>     *         segment of the file is being returned.</em>
<a name="562" href="#562">562</a> <em>     *         Null is returned if errors occur (file not found or io exception)</em>
<a name="563" href="#563">563</a> <em>     *         If a PatternSyntaxException occurs, it's error message will be</em>
<a name="564" href="#564">564</a> <em>     *         returned and the informational string will be empty (not null).</em>
<a name="565" href="#565">565</a> <em>     */</em>
<a name="566" href="#566">566</a>     <strong>public</strong> <strong>static</strong> String[] getByRegExpr(String aFileName, 
<a name="567" href="#567">567</a>                                         String regExpr, 
<a name="568" href="#568">568</a>                                         String addLines, 
<a name="569" href="#569">569</a>                                         <strong>boolean</strong> prependLineNumbers,
<a name="570" href="#570">570</a>                                         <strong>int</strong> skipFirstMatches,
<a name="571" href="#571">571</a>                                         <strong>int</strong> numberOfMatches){
<a name="572" href="#572">572</a>         <strong>try</strong> {
<a name="573" href="#573">573</a>             File f = <strong>new</strong> File(aFileName);
<a name="574" href="#574">574</a>             <strong>return</strong> getByRegExpr(
<a name="575" href="#575">575</a>                     <strong>new</strong> FileReader(f),
<a name="576" href="#576">576</a>                     regExpr,
<a name="577" href="#577">577</a>                     addLines,
<a name="578" href="#578">578</a>                     prependLineNumbers,
<a name="579" href="#579">579</a>                     skipFirstMatches,
<a name="580" href="#580">580</a>                     numberOfMatches,
<a name="581" href="#581">581</a>                     f.length());
<a name="582" href="#582">582</a>         } <strong>catch</strong> (FileNotFoundException e) {
<a name="583" href="#583">583</a>             e.printStackTrace();
<a name="584" href="#584">584</a>             <strong>return</strong> <strong>null</strong>;
<a name="585" href="#585">585</a>         }
<a name="586" href="#586">586</a>     }
<a name="587" href="#587">587</a>