关于Compass＋Spring 全文搜索的问题 我的个人站点：http://mao52.com

    最近想使用Compass＋Spring ＋Lucene做全文搜索，在网上找了些代码，但是没有完整的。发现网上的东西都是一枝半解，在自己的机器上调试了一下，但没有成功，希望有识之士帮看一下。

错误如下：

java.lang.NullPointerException
	sc.compass.CompassSearchService.search(CompassSearchService.java:48)
	sc.util.action.SearchAction.s(SearchAction.java:115)
	sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	java.lang.reflect.Method.invoke(Method.java:585)
	org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:280)
	org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:216)
	org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
	org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
	org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
	org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

由于本人对这几个类的代码很陌生，不知道问题出在哪里，原代码如下：

package sc.compass;
import org.compass.core.Compass;
import org.compass.core.CompassCallback;
import org.compass.core.CompassDetachedHits;
import org.compass.core.CompassException;
import org.compass.core.Compass;
import org.compass.core.CompassQuery;
import org.compass.core.CompassSession;
import org.compass.core.CompassTemplate;
import org.compass.core.CompassTransaction;
import org.compass.spring.web.mvc.CompassSearchCommand;
import org.compass.spring.web.mvc.CompassSearchResults;
import org.springframework.beans.factory.InitializingBean;
import sc.compass.AdvancedSearchCommand.CompassSort;
/**
 * 仿照 {@link org.compass.spring.web.mvc.CompassSearchController}
 * 中的代码，构建了一个Service，方便不使用Spring MVC 
 *
 * @see org.compass.spring.web.mvc.CompassSearchController
 * @see org.compass.spring.web.mvc.AbstractCompassCommandController
 */
public class CompassSearchService implements InitializingBean {
    /**
     * 每页显示的条目数量
     */
    private Integer pageSize;
    private Compass compass;
    private CompassTemplate compassTemplate;
    /**
     * 公开的搜索接口，返回匹配的搜索结果，与
     * {@link org.compass.spring.web.mvc.CompassSearchController#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, Object, org.springframework.validation.BindException)
     * 处理相似
     *
     * @param command
     * @return
     * @see org.compass.spring.web.mvc.CompassSearchController#handle(javax.servlet.http.HttpServletRequest,
     *      javax.servlet.http.HttpServletResponse, java.lang.Object,
     *      org.springframework.validation.BindException)
     */
    public CompassSearchResults search(final CompassSearchCommand command) {
        CompassSearchResults searchResults = (CompassSearchResults) getCompassTemplate()
                .execute(
                        CompassTransaction.TransactionIsolation.READ_ONLY_READ_COMMITTED,
                        new CompassCallback() {
                            public Object doInCompass(CompassSession session)
                                    throws CompassException {
                                return performSearch(command, session);
                            }
                        });
        return searchResults;
    }
    /**
     * 通过此方法调用搜索引擎，进行结果匹配搜索
     *
     * @param searchCommand
     * @param session
     * @return
     * @see org.compass.spring.web.mvc.CompassSearchController#performSearch(org.compass.spring.web.mvc.CompassSearchCommand,
     *      org.compass.core.CompassSession)
     */
    protected CompassSearchResults performSearch(
            CompassSearchCommand searchCommand, CompassSession session) {
        if (AdvancedSearchCommand.class.isAssignableFrom(searchCommand
                .getClass())) {
            AdvancedSearchCommand advancedCommand = (AdvancedSearchCommand) searchCommand;
            advancedCommand.setupQuery();
        }
        long time = System.currentTimeMillis();
        CompassQuery query = buildQuery(searchCommand, session);
        Compass hits = query.hits();
        CompassDetachedHits detachedHits;
        CompassSearchResults.Page[] pages = null;
        if (pageSize == null) {
            doProcessBeforeDetach(searchCommand, session, hits, -1, -1);
            detachedHits = hits.detach();
        } else {
            int iPageSize = pageSize.intValue();
            int page = 0;
            int hitsLength = hits.getLength();
            if (searchCommand.getPage() != null) {
                page = searchCommand.getPage().intValue();
            }
            int from = page * iPageSize;
            if (from > hits.getLength()) {
                // 如果起始的条目大于搜索到的条目
                from = hits.getLength() - iPageSize;
                doProcessBeforeDetach(searchCommand, session, hits, from,
                        hitsLength);
                detachedHits = hits.detach(from, hitsLength);
            } else if ((from + iPageSize) > hitsLength) {
                // 结束的条目大于搜索到的结果
                doProcessBeforeDetach(searchCommand, session, hits, from,
                        hitsLength);
                detachedHits = hits.detach(from, hitsLength);
            } else {
                // 中间的页码，直接取出相应的条目
                doProcessBeforeDetach(searchCommand, session, hits, from,
                        iPageSize);
                detachedHits = hits.detach(from, iPageSize);
            }
            doProcessAfterDetach(searchCommand, session, detachedHits);
            int numberOfPages = (int) Math.ceil((float) hitsLength / iPageSize);
            pages = new CompassSearchResults.Page[numberOfPages];
            for (int i = 0; i < pages.length; i++) {
                pages[i] = new CompassSearchResults.Page();
                pages[i].setFrom(i * iPageSize + 1);
                pages[i].setSize(iPageSize);
                pages[i].setTo((i + 1) * iPageSize);
                if (from >= (pages[i].getFrom() - 1) && from < pages[i].getTo()) {
                    pages[i].setSelected(true);
                } else {
                    pages[i].setSelected(false);
                }
            }
            if (numberOfPages > 0) {
                CompassSearchResults.Page lastPage = pages[numberOfPages - 1];
                if (lastPage.getTo() > hitsLength) {
                    lastPage.setSize(hitsLength - lastPage.getFrom());
                    lastPage.setTo(hitsLength);
                }
            }
        }
        time = System.currentTimeMillis() - time;
        CompassSearchResults searchResults = new CompassSearchResults(
                detachedHits.getHits(), time);
        searchResults.setPages(pages);
        return searchResults;
    }
    /**
     * 构建Lucene 搜索器
     *
     * @param searchCommand
     * @param session
     * @return
     */
    protected CompassQuery buildQuery(CompassSearchCommand searchCommand,
                                      CompassSession session) {
        CompassQuery query = session.queryBuilder().queryString(
                searchCommand.getQuery().trim()).toQuery();
        if (AdvancedSearchCommand.class.isAssignableFrom(searchCommand
                .getClass())) {
            AdvancedSearchCommand advancedSearchCommand = (AdvancedSearchCommand) searchCommand;
            for (CompassSort sort : advancedSearchCommand.getSortMap()) {
                query.addSort(sort.name, sort.type, sort.direction);
            }
        }
        return query;
    }
    /**
     * 在detach 之前，可以做一些操作。比如highlighting...
     *
     * @param searchCommand
     * @param session
     * @param hits
     * @param from          需要注意的是，如果pageSize 没有指定，那么这里传入的参数为-1
     * @param size
     */
    protected void doProcessBeforeDetach(CompassSearchCommand searchCommand,
                                         CompassSession session, Compass hits, int from, int size) {
    }
    /**
     * An option to perform any type of processing before the hits are detached.
     */
    protected void doProcessAfterDetach(CompassSearchCommand searchCommand,
                                        CompassSession session, CompassDetachedHits hits) {
    }
    public void afterPropertiesSet() throws Exception {
        if (compass == null) {
            throw new IllegalArgumentException("Must set compass proerty");
        }
        this.compassTemplate = new CompassTemplate(compass);
    }
    public Integer getPageSize() {
        return pageSize;
    }
    public void setPageSize(Integer pageSize) {
        this.pageSize = pageSize;
    }
    public void setCompass(Compass compass) {
        this.compass = compass;
    }
    protected CompassTemplate getCompassTemplate() {
        return this.compassTemplate;
    }
}
Action如下：
 public ActionForward s(ActionMapping mapping, ActionForm form, HttpServletRequest request,
              HttpServletResponse response) throws Exception {
    CompassSearchService aa = new CompassSearchService();
    AdvancedSearchCommand ac = new AdvancedSearchCommand();
    
    //String sm = request.getParameter("query");
    ac.addSort("临床医学科研程序与方法", "String", true);
    CompassSearchResults  result = aa.search(ac);
    for(int i=0;i       Compas hits=result.getHits()[i];
       Book book=(Book)hits.getData();
       System.out.println(book.getSm());
       
       System.out.println(book.getId());
      }
    //request.setAttribute("result", result);
    return mapping.findForward("test");
    
   }

评论

2 楼 shaucle 2006-12-22  

或手工注入compassTemplate

1 楼 shaucle 2006-12-22  

CompassSearchService要从spring中取得！

晕死，这是很低级的问题啊！