任務(wù)四新聞發(fā)布系統(tǒng)－訪問數(shù)據(jù)庫(kù)實(shí)驗(yàn)3數(shù)據(jù)庫(kù)操作實(shí)驗(yàn)?zāi)康模?.掌握數(shù)據(jù)庫(kù)新聞數(shù)據(jù)表增刪改查的方法；掌握數(shù)據(jù)庫(kù)新聞?lì)悇e數(shù)據(jù)表增刪改查的方法（自行補(bǔ)充）；掌握數(shù)據(jù)庫(kù)用戶數(shù)據(jù)庫(kù)增刪改查的方法（自行補(bǔ)充）實(shí)驗(yàn)步驟：新建NewsDao接口publicinterfaceNewsDao{ publicList<News>search();//查詢所有新聞 publicList<News>search(intt_id);//根據(jù)新聞?lì)悇eID查詢新聞 publicList<News>searchByNtitle(Stringn_title);//根據(jù)新聞標(biāo)題的關(guān)鍵字查詢新聞 publicList<News>searchByNcontent(Stringn_content);//根據(jù)新聞內(nèi)容的關(guān)鍵字查詢新聞 publicNewssearchByNid(intn_id);//根據(jù)新聞ID查詢新聞 publicbooleanadd(Newsnews);//添加新聞 publicbooleandelete(intid);//根據(jù)新聞ID刪除新聞 publicbooleanupdate(Newsnews);//修改新聞}新建NewsDao接口的實(shí)現(xiàn)類NewsDaoImplpublicclassNewsDaoImplextendsBaseDaoimplementsNewsDao{｝接口實(shí)現(xiàn)類NewsDaoImpl實(shí)現(xiàn)NewsDao接口中所有的抽象方法publicList<News>search(){//查詢所有新聞 List<News>list=newArrayList(); Stringsql="select*fromnrc_news"; try{ super.getConnection(); pstm=con.prepareStatement(sql); rs=pstm.executeQuery(); while(rs.next()){ Newsnews=newNews(); news.setN_id(rs.getInt("n_id")); news.setN_title(rs.getString("n_title")); news.setN_content(rs.getString("n_content")); news.setT_id(rs.getInt("t_id")); news.setN_publishtime(rs.getString("n_publishtime"));news.setN_source(rs.getString("n_source")); list.add(news); } }catch(Exceptione){ e.printStackTrace(); }finally{ super.closeAll(); } returnlist; }//根據(jù)新聞?lì)悇eID查詢新聞 publicListsearch(intt_id){ Listlist=newArrayList(); Stringsql="select*fromnrc_newswheret_id=?"; try{ super.getConnection(); pstm=con.prepareStatement(sql); pstm.setInt(1,t_id); rs=pstm.executeQuery(); while(rs.next()){ Newsnews=newNews(); news.setN_id(rs.getInt(1)); news.setN_title(rs.getString(2)); news.setN_content(rs.getString(3)); news.setT_id(rs.getInt(4)); news.setN_publishtime(rs.getString(5));news.setN_source(rs.getString("n_source")); list.add(news); } }catch(Exceptione){ e.printStackTrace(); }finally{ super.closeAll(); } returnlist; } //根據(jù)新聞ID查詢新聞publicNewssearchByNid(intn_id){ Newsnews=null; Stringsql="select*fromnrc_newswheren_id=?"; try{ super.getConnection(); pstm=con.prepareStatement(sql); pstm.setInt(1,n_id); rs=pstm.executeQuery(); if(rs.next()){ Stringn_title=rs.getString("n_title"); Stringn_content=rs.getString("n_content"); intt_id=rs.getInt("t_id"); Stringn_publishtime=rs.getString("n_publishtime");Stringn_source=rs.getString("n_source"); news=newNews(n_id,n_title,n_content,t_id,n_publishtime,n_source); } }catch(Exceptione){ e.printStackTrace(); }finally{ closeAll(); } returnnews; }//根據(jù)新聞標(biāo)題模糊查詢新聞 publicListsearchByNtitle(Stringn_title){ Listlist=newArrayList(); Stringsql="SELECT*FROMnrc_newsWHEREN_TITLELIKE?ORDERBYN_IDDESC"; try{ super.getConnection(); pstm=con.prepareStatement(sql); pstm.setString(1,"%"+n_title+"%"); rs=pstm.executeQuery(); while(rs.next()){ Newsnews=newNews(); news.setN_id(rs.getInt("n_id")); news.setN_title(rs.getString("n_title")); news.setN_content(rs.getString("n_content")); news.setT_id(rs.getInt("t_id")); news.setN_publishtime(rs.getString("n_publishtime")); news.setN_source(rs.getString("n_source"));list.add(news); } }catch(Exceptione){ e.printStackTrace(); }finally{ super.closeAll(); } returnlist; }//根據(jù)新聞內(nèi)容模糊查詢新聞 publicListsearchByNcontent(Stringn_content){ Listlist=newArrayList(); Stringsql="SELECT*FROMnrc_newsWHEREN_CONTENTLIKE?ORDERBYN_IDDESC"; try{ super.getConnection(); pstm=con.prepareStatement(sql); pstm.setString(1,"%"+n_content+"%"); rs=pstm.executeQuery(); while(rs.next()){ Newsnews=newNews(); news.setN_id(rs.getInt("n_id")); news.setN_title(rs.getString("n_title")); news.setN_content(rs.getString("n_content")); news.setT_id(rs.getInt("t_id")); news.setN_publishtime(rs.getString("n_publishtime"));news.setN_source(rs.getString("n_source")); list.add(news); } }catch(Exceptione){ e.printStackTrace(); }finally{ super.closeAll(); } returnlist; }//添加新聞publicbooleanadd(Newsnews){ booleanflag=false; try{ super.getConnection(); Stringsql="insertintonrc_news(n_title,n_content,t_id,n_publishtime,n_source)values(?,?,?,?,?)"; if(i>0){ System.out.println("插入新聞成功！"); } flag=true; }catch(Exceptione){ e.printStackTrace(); }finally{ //釋放資源 super.closeAll(); } returnflag; }//根據(jù)新聞ID刪除新聞 publicbooleandelete(intid){ booleanflag=false; try{ super.getConnection(); Stringsql="deletefromnrc_newswheren_id=?"; //處理執(zhí)行結(jié)果 if(i>0){ System.out.println("刪除新聞成功！"); } flag=true; }catch(Exceptione){ e.printStackTrace(); }finally{ //釋放資源 super.closeAll(); } returnflag; }//修改新聞 publicbooleanupdate(Newsnews){ booleanflag=false; try{ super.getConnection(); Stringsql="updatenrc_newssetn_title=?,n_content=?,t_id=?,n_publishtime=?,n_source=?wheren_id=?"; //處理執(zhí)行結(jié)果 if(i>0){ System.out.println("修改新聞成功！"); } flag=true; }catch(Exceptione){ e.printStackTrace(); }finally{ //釋放資源 super.closeAll(); } returnflag; }}4.使用測(cè)試類測(cè)試數(shù)據(jù)庫(kù)訪問與結(jié)果數(shù)據(jù)顯示publicclassTest{publicstaticvoidmain(String[]args){NewsDaoImplnewsDao=newNewsDaoImpl();ListnewsList=newArr