主要是讲解一下点赞功能实现的思路。
首先实现页面端js控制点赞数的增减，这一步很简单。按钮点击事件绑定，控制点赞数的增减。在数据库中设计一个表（praise_tab）,表的列（文章点赞，评论点赞） id INT PRIMARY KEY AUTO_INCREMENT, userid VARCHAR(20) NOT NULL, articleid INT DEFAULT 0, commentid INT DEFAULT 0 主要是，用户主键，文章主键，评论主键，形成一个记录，当用户点赞后插入一条数据。文章id，评论id默认为0，区分是对文章点赞还是对评论点赞。ajax实现对后台提交数据与返回判断值。点击按钮触发priase函数，ajax向后台提交，userId,articleId,commentId,其中给文章点赞，则commentId为0,反之同样如此。以下是简单实现代码
js: //praiseN,pra为span的id function priase(articleid,commentid,praiseN,pra){ var type = "json"; var praiseNum = parseInt(document.getElementById(praiseN).innerHTML); $.ajax({ url:"${pageContext.request.contextPath}/RecivePraiseServlet?sendType=post&dataType="+type, data:{"anthorid":'${sessionScope.user.userId}',"articleid":articleid,"commentid":commentid}, type: "post", dataType:type, success:function(data){ if("json" == type){ if(data != undefined && data != null){ var flag = data.praiseflag; // 1已点过赞 if(flag == 0){ document.getElementById(praiseN).innerHTML = praiseNum + 1; $('#'+pra).css("color","red"); }else if(flag == 1){ alert("你已经点过赞了！"); $('#'+pra).css("color","red"); } } } } }); } body: <a href="javascript:void(0)" onclick="priase(${Article.aid },0,'praiseOne','praiseTwo')"><span id="praiseTwo">赞</span></a> <span id="praiseOne" >${Article.articlePraiseNum }</span> servlet: public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { StringBuffer sb = new StringBuffer(""); PraiseService praises = new PraiseServiceImpl(); ArticleService ars = new ArticleServiceImpl(); CommentService cms = new CommentServiceImpl(); request.setCharacterEncoding("utf-8"); String userId = request.getParameter("anthorid"); String articleId = request.getParameter("articleid"); String commentId = request.getParameter("commentid"); String dataType = request.getParameter("dataType"); String sendType = request.getParameter("sendType"); if ("json".equals(dataType)){ if(articleId != null && !articleId.equals("0")){ //查找是否有对文章点赞记录 Praise pr = praises.findArticlePraise(Integer.parseInt(articleId), userId); if(pr != null){ sb.append("{"); sb.append("\"praiseflag\":1"); sb.append("}"); }else{ ars.addPraiseNum(Integer.parseInt(articleId)); praises.addArticlePriase(Integer.parseInt(articleId), userId); sb.append("{"); sb.append("\"praiseflag\":0"); sb.append("}"); } } if(commentId != null && !commentId.equals("0")){ //查找是否有对评论点赞记录 Praise pr = praises.findCommentPraise(Integer.parseInt(commentId), userId); if(pr != null){ sb.append("{"); sb.append("\"praiseflag\":1"); sb.append("}"); }else{ cms.addCommentNum(Integer.parseInt(commentId)); praises.addCommentPraise(Integer.parseInt(commentId), userId); sb.append("{"); sb.append("\"praiseflag\":0"); sb.append("}"); } } response.setContentType("text/html;charset=utf-8"); } PrintWriter out = response.getWriter(); out.println(sb.toString()); out.flush(); out.close(); }代码比较简单，主要是思路很重要！
