diskfileitem.html

java 的上传功能很强大的实施上述事实上说是

<a name="539" href="#539">539</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> setFormField(<strong class="jxr_keyword">boolean</strong> state) {
<a name="540" href="#540">540</a>         isFormField = state;
<a name="541" href="#541">541</a>     }
<a name="542" href="#542">542</a> 
<a name="543" href="#543">543</a> 
<a name="544" href="#544">544</a>     <em class="jxr_javadoccomment">/**</em>
<a name="545" href="#545">545</a> <em class="jxr_javadoccomment">     * Returns an {@link java.io.OutputStream OutputStream} that can</em>
<a name="546" href="#546">546</a> <em class="jxr_javadoccomment">     * be used for storing the contents of the file.</em>
<a name="547" href="#547">547</a> <em class="jxr_javadoccomment">     *</em>
<a name="548" href="#548">548</a> <em class="jxr_javadoccomment">     * @return An {@link java.io.OutputStream OutputStream} that can be used</em>
<a name="549" href="#549">549</a> <em class="jxr_javadoccomment">     *         for storing the contensts of the file.</em>
<a name="550" href="#550">550</a> <em class="jxr_javadoccomment">     *</em>
<a name="551" href="#551">551</a> <em class="jxr_javadoccomment">     * @throws IOException if an error occurs.</em>
<a name="552" href="#552">552</a> <em class="jxr_javadoccomment">     */</em>
<a name="553" href="#553">553</a>     <strong class="jxr_keyword">public</strong> OutputStream getOutputStream()
<a name="554" href="#554">554</a>         <strong class="jxr_keyword">throws</strong> IOException {
<a name="555" href="#555">555</a>         <strong class="jxr_keyword">if</strong> (dfos == <strong class="jxr_keyword">null</strong>) {
<a name="556" href="#556">556</a>             File outputFile = getTempFile();
<a name="557" href="#557">557</a>             dfos = <strong class="jxr_keyword">new</strong> DeferredFileOutputStream(sizeThreshold, outputFile);
<a name="558" href="#558">558</a>         }
<a name="559" href="#559">559</a>         <strong class="jxr_keyword">return</strong> dfos;
<a name="560" href="#560">560</a>     }
<a name="561" href="#561">561</a> 
<a name="562" href="#562">562</a> 
<a name="563" href="#563">563</a>     <em class="jxr_comment">// --------------------------------------------------------- Public methods</em>
<a name="564" href="#564">564</a> 
<a name="565" href="#565">565</a> 
<a name="566" href="#566">566</a>     <em class="jxr_javadoccomment">/**</em>
<a name="567" href="#567">567</a> <em class="jxr_javadoccomment">     * Returns the {@link java.io.File} object for the &lt;code&gt;FileItem&lt;/code&gt;'s</em>
<a name="568" href="#568">568</a> <em class="jxr_javadoccomment">     * data's temporary location on the disk. Note that for</em>
<a name="569" href="#569">569</a> <em class="jxr_javadoccomment">     * &lt;code&gt;FileItem&lt;/code&gt;s that have their data stored in memory,</em>
<a name="570" href="#570">570</a> <em class="jxr_javadoccomment">     * this method will return &lt;code&gt;null&lt;/code&gt;. When handling large</em>
<a name="571" href="#571">571</a> <em class="jxr_javadoccomment">     * files, you can use {@link java.io.File#renameTo(java.io.File)} to</em>
<a name="572" href="#572">572</a> <em class="jxr_javadoccomment">     * move the file to new location without copying the data, if the</em>
<a name="573" href="#573">573</a> <em class="jxr_javadoccomment">     * source and destination locations reside within the same logical</em>
<a name="574" href="#574">574</a> <em class="jxr_javadoccomment">     * volume.</em>
<a name="575" href="#575">575</a> <em class="jxr_javadoccomment">     *</em>
<a name="576" href="#576">576</a> <em class="jxr_javadoccomment">     * @return The data file, or &lt;code&gt;null&lt;/code&gt; if the data is stored in</em>
<a name="577" href="#577">577</a> <em class="jxr_javadoccomment">     *         memory.</em>
<a name="578" href="#578">578</a> <em class="jxr_javadoccomment">     */</em>
<a name="579" href="#579">579</a>     <strong class="jxr_keyword">public</strong> File getStoreLocation() {
<a name="580" href="#580">580</a>         <strong class="jxr_keyword">return</strong> dfos == <strong class="jxr_keyword">null</strong> ? <strong class="jxr_keyword">null</strong> : dfos.getFile();
<a name="581" href="#581">581</a>     }
<a name="582" href="#582">582</a> 
<a name="583" href="#583">583</a> 
<a name="584" href="#584">584</a>     <em class="jxr_comment">// ------------------------------------------------------ Protected methods</em>
<a name="585" href="#585">585</a> 
<a name="586" href="#586">586</a> 
<a name="587" href="#587">587</a>     <em class="jxr_javadoccomment">/**</em>
<a name="588" href="#588">588</a> <em class="jxr_javadoccomment">     * Removes the file contents from the temporary storage.</em>
<a name="589" href="#589">589</a> <em class="jxr_javadoccomment">     */</em>
<a name="590" href="#590">590</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">void</strong> finalize() {
<a name="591" href="#591">591</a>         File outputFile = dfos.getFile();
<a name="592" href="#592">592</a> 
<a name="593" href="#593">593</a>         <strong class="jxr_keyword">if</strong> (outputFile != <strong class="jxr_keyword">null</strong> &amp;&amp; outputFile.exists()) {
<a name="594" href="#594">594</a>             outputFile.delete();
<a name="595" href="#595">595</a>         }
<a name="596" href="#596">596</a>     }
<a name="597" href="#597">597</a> 
<a name="598" href="#598">598</a> 
<a name="599" href="#599">599</a>     <em class="jxr_javadoccomment">/**</em>
<a name="600" href="#600">600</a> <em class="jxr_javadoccomment">     * Creates and returns a {@link java.io.File File} representing a uniquely</em>
<a name="601" href="#601">601</a> <em class="jxr_javadoccomment">     * named temporary file in the configured repository path. The lifetime of</em>
<a name="602" href="#602">602</a> <em class="jxr_javadoccomment">     * the file is tied to the lifetime of the &lt;code&gt;FileItem&lt;/code&gt; instance;</em>
<a name="603" href="#603">603</a> <em class="jxr_javadoccomment">     * the file will be deleted when the instance is garbage collected.</em>
<a name="604" href="#604">604</a> <em class="jxr_javadoccomment">     *</em>
<a name="605" href="#605">605</a> <em class="jxr_javadoccomment">     * @return The {@link java.io.File File} to be used for temporary storage.</em>
<a name="606" href="#606">606</a> <em class="jxr_javadoccomment">     */</em>
<a name="607" href="#607">607</a>     <strong class="jxr_keyword">protected</strong> File getTempFile() {
<a name="608" href="#608">608</a>         <strong class="jxr_keyword">if</strong> (tempFile == <strong class="jxr_keyword">null</strong>) {
<a name="609" href="#609">609</a>             File tempDir = repository;
<a name="610" href="#610">610</a>             <strong class="jxr_keyword">if</strong> (tempDir == <strong class="jxr_keyword">null</strong>) {
<a name="611" href="#611">611</a>                 tempDir = <strong class="jxr_keyword">new</strong> File(System.getProperty(<span class="jxr_string">"java.io.tmpdir"</span>));
<a name="612" href="#612">612</a>             }
<a name="613" href="#613">613</a> 
<a name="614" href="#614">614</a>             String tempFileName =
<a name="615" href="#615">615</a>                 <span class="jxr_string">"upload_"</span> + UID + <span class="jxr_string">"_"</span> + getUniqueId() + <span class="jxr_string">".tmp"</span>;
<a name="616" href="#616">616</a> 
<a name="617" href="#617">617</a>             tempFile = <strong class="jxr_keyword">new</strong> File(tempDir, tempFileName);
<a name="618" href="#618">618</a>         }
<a name="619" href="#619">619</a>         <strong class="jxr_keyword">return</strong> tempFile;
<a name="620" href="#620">620</a>     }
<a name="621" href="#621">621</a> 
<a name="622" href="#622">622</a> 
<a name="623" href="#623">623</a>     <em class="jxr_comment">// -------------------------------------------------------- Private methods</em>
<a name="624" href="#624">624</a> 
<a name="625" href="#625">625</a> 
<a name="626" href="#626">626</a>     <em class="jxr_javadoccomment">/**</em>
<a name="627" href="#627">627</a> <em class="jxr_javadoccomment">     * Returns an identifier that is unique within the class loader used to</em>
<a name="628" href="#628">628</a> <em class="jxr_javadoccomment">     * load this class, but does not have random-like apearance.</em>
<a name="629" href="#629">629</a> <em class="jxr_javadoccomment">     *</em>
<a name="630" href="#630">630</a> <em class="jxr_javadoccomment">     * @return A String with the non-random looking instance identifier.</em>
<a name="631" href="#631">631</a> <em class="jxr_javadoccomment">     */</em>
<a name="632" href="#632">632</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> String getUniqueId() {
<a name="633" href="#633">633</a>         <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> limit = 100000000;
<a name="634" href="#634">634</a>         <strong class="jxr_keyword">int</strong> current;
<a name="635" href="#635">635</a>         <strong class="jxr_keyword">synchronized</strong> (DiskFileItem.<strong class="jxr_keyword">class</strong>) {
<a name="636" href="#636">636</a>             current = counter++;
<a name="637" href="#637">637</a>         }
<a name="638" href="#638">638</a>         String id = Integer.toString(current);
<a name="639" href="#639">639</a> 
<a name="640" href="#640">640</a>         <em class="jxr_comment">// If you manage to get more than 100 million of ids, you'll</em>
<a name="641" href="#641">641</a>         <em class="jxr_comment">// start getting ids longer than 8 characters.</em>
<a name="642" href="#642">642</a>         <strong class="jxr_keyword">if</strong> (current &lt; limit) {
<a name="643" href="#643">643</a>             id = (<span class="jxr_string">"00000000"</span> + id).substring(id.length());
<a name="644" href="#644">644</a>         }
<a name="645" href="#645">645</a>         <strong class="jxr_keyword">return</strong> id;
<a name="646" href="#646">646</a>     }
<a name="647" href="#647">647</a> 
<a name="648" href="#648">648</a> 
<a name="649" href="#649">649</a> 
<a name="650" href="#650">650</a> 
<a name="651" href="#651">651</a>     <em class="jxr_javadoccomment">/**</em>
<a name="652" href="#652">652</a> <em class="jxr_javadoccomment">     * Returns a string representation of this object.</em>
<a name="653" href="#653">653</a> <em class="jxr_javadoccomment">     *</em>
<a name="654" href="#654">654</a> <em class="jxr_javadoccomment">     * @return a string representation of this object.</em>
<a name="655" href="#655">655</a> <em class="jxr_javadoccomment">     */</em>
<a name="656" href="#656">656</a>     <strong class="jxr_keyword">public</strong> String toString() {
<a name="657" href="#657">657</a>         <strong class="jxr_keyword">return</strong> <span class="jxr_string">"name="</span> + <strong class="jxr_keyword">this</strong>.getName()
<a name="658" href="#658">658</a>             + <span class="jxr_string">", StoreLocation="</span>
<a name="659" href="#659">659</a>             + String.valueOf(<strong class="jxr_keyword">this</strong>.getStoreLocation())
<a name="660" href="#660">660</a>             + <span class="jxr_string">", size="</span>
<a name="661" href="#661">661</a>             + <strong class="jxr_keyword">this</strong>.getSize()
<a name="662" href="#662">662</a>             + <span class="jxr_string">"bytes, "</span>
<a name="663" href="#663">663</a>             + <span class="jxr_string">"isFormField="</span> + isFormField()
<a name="664" href="#664">664</a>             + <span class="jxr_string">", FieldName="</span>
<a name="665" href="#665">665</a>             + <strong class="jxr_keyword">this</strong>.getFieldName();
<a name="666" href="#666">666</a>     }
<a name="667" href="#667">667</a> 
<a name="668" href="#668">668</a> 
<a name="669" href="#669">669</a>     <em class="jxr_comment">// -------------------------------------------------- Serialization methods</em>
<a name="670" href="#670">670</a> 
<a name="671" href="#671">671</a> 
<a name="672" href="#672">672</a>     <em class="jxr_javadoccomment">