atom10parser.html

解析RSS工具源码

<a name="436" href="#436">436</a>         <strong>return</strong> absoluteURIPattern.matcher(uri).find();
<a name="437" href="#437">437</a>     }
<a name="438" href="#438">438</a>     
<a name="439" href="#439">439</a>     <strong>private</strong> <strong>boolean</strong> isRelativeURI(String uri) {
<a name="440" href="#440">440</a>         <strong>return</strong> !isAbsoluteURI(uri);
<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>     * } </em>
<a name="445" href="#445">445</a> <em>     * Resolve URI based considering xml:base and baseURI.</em>
<a name="446" href="#446">446</a> <em>     * @param baseURI Base URI of feed</em>
<a name="447" href="#447">447</a> <em>     * @param parent  Parent from which to consider xml:base</em>
<a name="448" href="#448">448</a> <em>     * @param url     URL to be resolved</em>
<a name="449" href="#449">449</a> <em>     */</em>
<a name="450" href="#450">450</a>     <strong>private</strong> String resolveURI(String baseURI, Parent parent, String url) {
<a name="451" href="#451">451</a>         <strong>if</strong> (isRelativeURI(url)) {
<a name="452" href="#452">452</a>             url = (!<span class="string">"."</span>.equals(url) &amp;&amp; !<span class="string">"./"</span>.equals(url)) ? url : <span class="string">""</span>;
<a name="453" href="#453">453</a> 
<a name="454" href="#454">454</a>             <em class="comment">// Relative URI with parent</em>
<a name="455" href="#455">455</a>             <strong>if</strong> (parent != <strong>null</strong> &amp;&amp; parent instanceof Element) {
<a name="456" href="#456">456</a> 
<a name="457" href="#457">457</a>                 <em class="comment">// Do we have an xml:base?         </em>
<a name="458" href="#458">458</a>                 String xmlbase = ((Element)parent).getAttributeValue(
<a name="459" href="#459">459</a>                     <span class="string">"base"</span>, Namespace.XML_NAMESPACE);
<a name="460" href="#460">460</a>                 <strong>if</strong> (xmlbase != <strong>null</strong> &amp;&amp; xmlbase.trim().length() > 0) {
<a name="461" href="#461">461</a>                     <strong>if</strong> (isAbsoluteURI(xmlbase)) {
<a name="462" href="#462">462</a>                         <em class="comment">// Absolute xml:base, so form URI right now </em>
<a name="463" href="#463">463</a>                         <strong>if</strong> (url.startsWith(<span class="string">"/"</span>)) { 
<a name="464" href="#464">464</a>                             <em class="comment">// Host relative URI</em>
<a name="465" href="#465">465</a>                             <strong>int</strong> slashslash = xmlbase.indexOf(<span class="string">"//"</span>);
<a name="466" href="#466">466</a>                             <strong>int</strong> nextslash = xmlbase.indexOf(<span class="string">"/"</span>, slashslash + 2);
<a name="467" href="#467">467</a>                             <strong>if</strong> (nextslash != -1) xmlbase = xmlbase.substring(0, nextslash);
<a name="468" href="#468">468</a>                             <strong>return</strong> formURI(xmlbase, url); 
<a name="469" href="#469">469</a>                         }
<a name="470" href="#470">470</a>                         <strong>if</strong> (!xmlbase.endsWith(<span class="string">"/"</span>)) {
<a name="471" href="#471">471</a>                             <em class="comment">// Base URI is filename, strip it off </em>
<a name="472" href="#472">472</a>                             xmlbase = xmlbase.substring(0, xmlbase.lastIndexOf(<span class="string">"/"</span>));
<a name="473" href="#473">473</a>                         }
<a name="474" href="#474">474</a>                         <strong>return</strong> formURI(xmlbase, url);
<a name="475" href="#475">475</a>                     } <strong>else</strong> {
<a name="476" href="#476">476</a>                         <em class="comment">// Relative xml:base, so walk up tree</em>
<a name="477" href="#477">477</a>                         <strong>return</strong> resolveURI(baseURI, parent.getParent(), 
<a name="478" href="#478">478</a>                             stripTrailingSlash(xmlbase) + <span class="string">"/"</span>+ stripStartingSlash(url));
<a name="479" href="#479">479</a>                     }
<a name="480" href="#480">480</a>                 }
<a name="481" href="#481">481</a>                 <em class="comment">// No xml:base so walk up tree</em>
<a name="482" href="#482">482</a>                 <strong>return</strong> resolveURI(baseURI, parent.getParent(), url);
<a name="483" href="#483">483</a> 
<a name="484" href="#484">484</a>             <em class="comment">// Relative URI with no parent (i.e. top of tree), so form URI right now</em>
<a name="485" href="#485">485</a>             } <strong>else</strong> <strong>if</strong> (parent == <strong>null</strong> || parent instanceof Document) {
<a name="486" href="#486">486</a>                 <strong>return</strong> formURI(baseURI, url);        
<a name="487" href="#487">487</a>             } 
<a name="488" href="#488">488</a>         }                
<a name="489" href="#489">489</a>         <strong>return</strong> url;
<a name="490" href="#490">490</a>     }
<a name="491" href="#491">491</a>         
<a name="492" href="#492">492</a>     <em>/**<em>*</em></em>
<a name="493" href="#493">493</a> <em>     * Find base URI of feed considering relative URIs.</em>
<a name="494" href="#494">494</a> <em>     * @param root Root element of feed.</em>
<a name="495" href="#495">495</a> <em>     */</em>
<a name="496" href="#496">496</a>     <strong>private</strong> String findBaseURI(Element root) throws MalformedURLException {
<a name="497" href="#497">497</a>         String ret = findAtomLink(root, <span class="string">"alternate"</span>);
<a name="498" href="#498">498</a>         <strong>if</strong> (ret != <strong>null</strong> &amp;&amp; isRelativeURI(ret)) {
<a name="499" href="#499">499</a>             String self = findAtomLink(root, <span class="string">"self"</span>);
<a name="500" href="#500">500</a>             <strong>if</strong> (self != <strong>null</strong>) {
<a name="501" href="#501">501</a>                 self = resolveURI(<strong>null</strong>, root, self);
<a name="502" href="#502">502</a>                 self = self.substring(0, self.lastIndexOf(<span class="string">"/"</span>));
<a name="503" href="#503">503</a>                 ret = resolveURI(self, root, ret);
<a name="504" href="#504">504</a>             }
<a name="505" href="#505">505</a>         }
<a name="506" href="#506">506</a>         <strong>return</strong> ret;
<a name="507" href="#507">507</a>     } 
<a name="508" href="#508">508</a>     
<a name="509" href="#509">509</a>     <em>/**<em>* </em></em>
<a name="510" href="#510">510</a> <em>     * Return URL string of Atom link element under parent element.</em>
<a name="511" href="#511">511</a> <em>     * Link with no rel attribute is considered to be rel="alternate"</em>
<a name="512" href="#512">512</a> <em>     * @param parent Consider only children of this parent element</em>
<a name="513" href="#513">513</a> <em>     * @param rel    Consider only links with this relationship</em>
<a name="514" href="#514">514</a> <em>     */</em>
<a name="515" href="#515">515</a>     <strong>private</strong> String findAtomLink(Element parent, String rel) {
<a name="516" href="#516">516</a>         String ret = <strong>null</strong>;
<a name="517" href="#517">517</a>         List linksList = parent.getChildren(<span class="string">"link"</span>, ns);
<a name="518" href="#518">518</a>         <strong>if</strong> (linksList != <strong>null</strong>) {
<a name="519" href="#519">519</a>             <strong>for</strong> (Iterator links = linksList.iterator(); links.hasNext(); ) {
<a name="520" href="#520">520</a>                 Element link = (Element)links.next();
<a name="521" href="#521">521</a>                 Attribute relAtt = link.getAttribute(<span class="string">"rel"</span>);
<a name="522" href="#522">522</a>                 Attribute hrefAtt = link.getAttribute(<span class="string">"href"</span>);
<a name="523" href="#523">523</a>                 <strong>if</strong> (   (relAtt == <strong>null</strong> &amp;&amp; <span class="string">"alternate"</span>.equals(rel)) 
<a name="524" href="#524">524</a>                     || (relAtt != <strong>null</strong> &amp;&amp; relAtt.getValue().equals(rel))) {
<a name="525" href="#525">525</a>                     ret = hrefAtt.getValue();
<a name="526" href="#526">526</a>                     <strong>break</strong>;
<a name="527" href="#527">527</a>                 }
<a name="528" href="#528">528</a>             }
<a name="529" href="#529">529</a>         }
<a name="530" href="#530">530</a>         <strong>return</strong> ret;
<a name="531" href="#531">531</a>     }
<a name="532" href="#532">532</a>         
<a name="533" href="#533">533</a>     <em>/**<em>* </em></em>
<a name="534" href="#534">534</a> <em>     * Form URI by combining base with append portion and giving </em>
<a name="535" href="#535">535</a> <em>     * special consideration to append portions that begin with ".."</em>
<a name="536" href="#536">536</a> <em>     * @param base   Base of URI, may end with trailing slash</em>
<a name="537" href="#537">537</a> <em>     * @param append String to append, may begin with slash or ".."</em>
<a name="538" href="#538">538</a> <em>     */</em>
<a name="539" href="#539">539</a>     <strong>private</strong> <strong>static</strong> String formURI(String base, String append) {
<a name="540" href="#540">540</a>         base = stripTrailingSlash(base);
<a name="541" href="#541">541</a>         append = stripStartingSlash(append);
<a name="542" href="#542">542</a>         <strong>if</strong> (append.startsWith(<span class="string">".."</span>)) {
<a name="543" href="#543">543</a>             String ret = <strong>null</strong>;
<a name="544" href="#544">544</a>             String[] parts = append.split(<span class="string">"/"</span>);
<a name="545" href="#545">545</a>             <strong>for</strong> (<strong>int</strong> i=0; i&lt;parts.length; i++) {
<a name="546" href="#546">546</a>                 <strong>if</strong> (<span class="string">".."</span>.equals(parts[i])) {
<a name="547" href="#547">547</a>                     <strong>int</strong> last = base.lastIndexOf(<span class="string">"/"</span>);
<a name="548" href="#548">548</a>                     <strong>if</strong> (last != -1) {
<a name="549" href="#549">549</a>                         base = base.substring(0, last);
<a name="550" href="#550">550</a>                         append = append.substring(3, append.length());
<a name="551" href="#551">551</a>                     }
<a name="552" href="#552">552</a>                     <strong>else</strong> <strong>break</strong>;
<a name="553" href="#553">553</a>                 }
<a name="554" href="#554">554</a>             }
<a name="555" href="#555">555</a>         }
<a name="556" href="#556">556</a>         <strong>return</strong> base + <span class="string">"/"</span> + append;
<a name="557" href="#557">557</a>     }
<a name="558" href="#558">558</a>     
<a name="559" href="#559">559</a>     <em>/**<em>* </em></em>
<a name="560" href="#560">560</a> <em>     * Strip starting slash from beginning of string.</em>
<a name="561" href="#561">561</a> <em>     */</em>
<a name="562" href="#562">562</a>     <strong>private</strong> <strong>static</strong> String stripStartingSlash(String s) {
<a name="563" href="#563">563</a>         <strong>if</strong> (s != <strong>null</strong> &amp;&amp; s.startsWith(<span class="string">"/"</span>)) {
<a name="564" href="#564">564</a>             s = s.substring(1, s.length());
<a name="565" href="#565">565</a>         }
<a name="566" href="#566">566</a>         <strong>return</strong> s;
<a name="567" href="#567">567</a>     }
<a name="568" href="#568">568</a>     
<a name="569" href="#569">569</a>     <em>/**<em>* </em></em>
<a name="570" href="#570">570</a> <em>     * Strip trailing slash from end of string.</em>
<a name="571" href="#571">571</a> <em>     */</em>
<a name="572" href="#572">572</a>     <strong>private</strong> <strong>static</strong> String stripTrailingSlash(String s) {
<a name="573" href="#573">573</a>         <strong>if</strong> (s != <strong>null</strong> &amp;&amp; s.endsWith(<span class="string">"/"</span>)) {
<a name="574" href="#574">574</a>             s = s.substring(0, s.length() - 1);
<a name="575" href="#575">575</a>         }
<a name="576" href="#576">576</a>         <strong>return</strong> s;
<a name="577" href="#577">577</a>     }
<a name="578" href="#578">578</a> }
</pre>
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