小确幸BBS论坛-2-首页

话说：
各位读者朋友，晚上好！这一篇展示首页。

难度系数：★★★☆☆
建议用时：1天实际用时1天
目录

工具类
首页面index.jsp
首页面样式
后端代码

首页面复杂点：
1.SQL语句复杂点，要统计下回复次数；

2.搜索。单独搜索简单，但是要实现在不同栏目下的搜索，就相对复杂些，而且不论搜索还是分栏目，分页都要带上；

1. 工具类

DBUtil 连接数据库
GetFormatTimeUtil 格式化时间
GetPreparedStatementUtil 获取PS对象，遍历参数
GetPropertyUtil 获取静态资源
GetStrToInt 字符串转int

DBUtil 连接数据库

package com.hmc.util;
/**
*
*2017年12月30日
*User:Meice
*下午8:35:12
*/import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;public class DBUtil {//封装连接数据库的方法//处理异常:java.sql.SQLNonTransientConnectionException: Could not create connection to database server.static  int retryCount = 5;  static  boolean transactionCompleted = false;  //1.加载驱动static {try {Class.forName(GetPropertyUtil.getVal("driver"));} catch (ClassNotFoundException e) {e.printStackTrace();}}//2.获取连接public static Connection getConn() {do {//分开放 尽量不要合并写在一块String url = GetPropertyUtil.getVal("url");String user = GetPropertyUtil.getVal("user");String password = GetPropertyUtil.getVal("password");try {Connection conn =   DriverManager.getConnection(url, user, password);return conn;} catch (SQLException e) {e.printStackTrace();String sqlState = e.getSQLState();if("08S01".equals(sqlState) || "40001".equals(sqlState)) {retryCount--;}else {retryCount = 0;}}return null;}while(!transactionCompleted && retryCount>0);}//3.关闭资源public static void closeConn(Connection conn,PreparedStatement ps,ResultSet rs) {//Alt + Shift + Z 抛出语句块异常try {if(rs != null) rs.close();if(ps != null) ps.close();if(conn != null) conn.close();} catch (SQLException e) {e.printStackTrace();}}}

GetFormatTimeUtil 格式化时间

package com.hmc.util;
import java.text.SimpleDateFormat;
import java.util.Date;/**
*
*2017年12月30日
*User:Meice
*下午9:44:05
*/
public class GetFormatTimeUtil {public static String getFormatTime(int TwelveOrTwentyFour) {Date date = new Date();SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss");SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");if(TwelveOrTwentyFour == 12) {return sdf2.format(date);}else if(TwelveOrTwentyFour == 24){return sdf.format(date);}else {return null;}}}

GetPreparedStatementUtil 获取PS对象，遍历参数

package com.hmc.util;
/**
*
*2017年12月30日
*User:Meice
*下午9:04:45
*/import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;public class GetPreparedStatementUtil {//定义获取PrepatedStatement对象public static PreparedStatement getPs(Connection conn,PreparedStatement ps,String sql,Object... params) {try {ps =       conn.prepareStatement(sql);//这样有无参数都可以搞定if(params!= null) {for(int i=0;i<params.length;i++) {ps.setObject((i+1),params[i]);}}return ps;} catch (SQLException e) {e.printStackTrace();}return null;}}

GetPropertyUtil 获取静态资源

package com.hmc.util;import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;/**
*
*2017年12月30日
*User:Meice
*下午8:49:31
*/
public class GetPropertyUtil {//获取静态资源public static String getVal(String key) {Properties pro = new Properties();InputStream is;try {is = new FileInputStream("D:\\WorkSpace\\eclipse\\xiaomeibbs\\db.properties");pro.load(is);return pro.getProperty(key);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return null;}}

GetStrToInt 字符串转int

package com.hmc.util;
/**
*
*2018年1月1日
*User:Meice
*上午11:46:00
*/
public class GetStrToInt {public static int getInt(String str) {if(str!= null && !str.equals("")) {return Integer.parseInt(str);}return 0;}
}

这里要总结一下下：
1）连接数据库，读取配置文件的时候，如果直接把配置文件放到工程目录下，测试是没有问题的，但是一旦涉及Servlet，就会找不到，所以要写绝对路径。

2）封装的时候，不要仅仅考虑方便，比如获取PreparedStatement，要考虑到每次都要用一个新的对象，让外界提供Connection conn,PrepatedStatement
这样，每次调用，对象都不同，避免调用过程中，对象发生混乱！

3）获取时间的工具类可有可无。处理数据库时间方式多样，一般有这几种：

a.数据库时间设置为varchar()，实体类为String，用我写的工具类来添加数据；
b.数据库时间直接设置为Date，传值的时候直接new Date()即可；
c.数据库时间直接设置为Date或者datetime，直接在SQL语句中传值now()；
d.数据库时间不要设置为timestamp.因为这个默认为now(),虽然根本都不用传值，但是只要数据发生变化，比如修改、删除，那么这个时间都会变成修改、删除的时间，这并不是我们想要的。

2. 首页面index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core"  prefix="c" %>
<!--Author:Meice 2017年12月30日下午12:13:19 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>小确幸论坛</title>
<!--  引入外部样式-->
<link href="css/textList.css"  rel="stylesheet" type="text/css"><style type="text/css">/* link visited hover active    love hate  */a:visited{color:gray;}a:hover{color: orange;}</style><!-- 如果当前栏目被选择，给一个样式 -->
<script type="text/javascript">function changeBgColor1() {//alert("进来了！");var a = document.getElementById("liOne");//a.setAttribute("background-color","orange");a.style.backgroundColor = "orange";}
</script></head>
<body>
<!--引入头部  --><jsp:include page="head.jsp"></jsp:include><!--搜索框的div  --><div id="search"><form action="textShow" method="get"><input type="text" name="search" style="width:300px;height:40px;"><input type="submit" value="搜索一下" style="width:60px;height:40px;"><input type="hidden" name="categoryId" value="${categoryId}"></form></div><!--登录后用户信息  --><div id="userInfo"><span class="userInfo">欢迎【${user.userNick}】!</span><br/><a href="userInfo" class="userInfo" style="color:orange;">个人中心</a><a href="login.jsp" class="userInfo">退出</a></div><!--栏目div  --><div id="category"><ul><!-- 前端不好，只能这样变化栏目背景色 --><c:if test="${categoryId==0 }"><li  style="background-color:rgb(104,189,69);"> <a href="textShow" onclick="changeBgColor1()">首页</a></li></c:if><c:if test="${categoryId!=0 }"><li >   <a href="textShow" onclick="changeBgColor1()">首页</a></li></c:if><c:if test="${categoryId ==1 }"><li id="liTwo" style="background-color:rgb(104,189,69);" >  <a href="textShow?categoryId=1">Java</a></li></c:if><c:if test="${categoryId !=1 }"><li id="liTwo"> <a href="textShow?categoryId=1">Java</a></li></c:if><c:if test="${categoryId ==2 }"><li   style="background-color:rgb(104,189,69);"><a href="textShow?categoryId=2">MySQL</a></li></c:if><c:if test="${categoryId !=2 }"><li><a href="textShow?categoryId=2">MySQL</a></li></c:if><c:if test="${categoryId ==3 }"><li  style="background-color:rgb(104,189,69);"><a href="textShow?categoryId=3">大数据</a></li></c:if><c:if test="${categoryId !=3 }"><li><a href="textShow?categoryId=3">大数据</a></li></c:if><c:if test="${categoryId == 4 }"><li style="background-color:rgb(104,189,69);"><a href="textShow?categoryId=4">人工智能</a></li></c:if><c:if test="${categoryId != 4 }"><li><a href="textShow?categoryId=4">人工智能</a></li></c:if><c:if test="${categoryId == 5 }"><li style="background-color:rgb(104,189,69);"><a href="textShow?categoryId=5">HTML5</a></li></c:if><c:if test="${categoryId != 5 }"><li><a href="textShow?categoryId=5">HTML5</a></li></c:if><c:if test="${categoryId == 6 }"><li  style="background-color:rgb(104,189,69);background-color: rgb();"><a href="textShow?categoryId=6">生活</a></li></c:if><c:if test="${categoryId !=6 }"><li><a href="textShow?categoryId=6">生活</a></li></c:if><c:if test="${categoryId == 7 }"><li  style="background-color:rgb(104,189,69);"><a href="textShow?categoryId=7">有趣有料</a></li></c:if><c:if test="${categoryId != 7 }"><li><a href="textShow?categoryId=7">有趣有料</a></li></c:if></ul></div><!--帖子列表div  --><div id="textList"><table border="1 solid green" width="90%" align="center"><thead><tr style="background-color: rgb(233,248,230);"><th>标题</th><th>作者</th><th>评论数量</th><th>发帖时间</th></tr></thead><tbody><!--遍历textList取值  --><c:if test="${ empty textList}"><tr><td colspan="4" style="color:red;font-weight:bolder;" align="center">It's a pity,未查询到数据奥~~</td></tr></c:if><c:forEach var="ListShow" items="${textList}"><c:if test="${!empty textList}"><tr><td><a href="textDetail?textId=${ListShow.textId}">${ListShow.title }</a></td><td align="center"><a href="#">${ListShow.user.userNick}</a></td><td align="center">${ListShow.replyCount }</td><td align="center">${ListShow.textTime}</td></tr></c:if></c:forEach><tr><td colspan="4" align="center" ><c:if test="${pageIndex>1 }"><button onclick="window.location.href='textShow?pageIndex=1&categoryId=${categoryId }&search=${search}'" style="width:50px;height:25px;" >首页</button><button onclick="window.location.href='textShow?pageIndex=${pageIndex-1}&categoryId=${categoryId }&search=${search}'">上一页</button></c:if><!--总页数要>10 才按照每页10条分页  --><c:if test="${totalPage>=10}"><!--处理前10页  --><c:if test="${pageIndex<=10 }"><c:forEach var="i" begin="1" end="10"><c:if test="${pageIndex==i}">${i}</c:if><c:if test="${pageIndex!=i }"><button onclick="window.location.href='textShow?pageIndex=${i}&categoryId=${categoryId }&search=${search}'" style="width:25px;height:25px;">${i}</button></c:if></c:forEach></c:if><!-- 处理大于10页 小于(totalPage-10)页 --><c:if test="${pageIndex>10 and pageIndex<(totalPage-4 )}"><c:forEach var="i" begin="${pageIndex-4 }" end="${pageIndex+5}"><c:if test="${pageIndex==i}">${i}</c:if><c:if test="${pageIndex!=i }"><button onclick="window.location.href='textShow?pageIndex=${i}&categoryId=${categoryId }&search=${search}'" style="width:25px;height:25px;">${i}</button></c:if></c:forEach></c:if><!-- 处理最后几页 --><c:if test="${pageIndex>=(totalPage-4) }"><c:forEach var="i" begin="${totalPage-9}" end="${totalPage}"><c:if test="${pageIndex==i}">${i}</c:if><c:if test="${pageIndex!=i }"><button onclick="window.location.href='textShow?pageIndex=${i}&categoryId=${categoryId }&search=${search}'" style="width:25px;height:25px;">${i}</button></c:if></c:forEach></c:if></c:if><!-- 总页数小于10  --><c:if test="${totalPage<10 }"><c:forEach var="i" begin="1" end="${totalPage}"><c:if test="${pageIndex==i}">${i}</c:if><c:if test="${pageIndex!=i }"><button onclick="window.location.href='textShow?pageIndex=${i}&categoryId=${categoryId }&search=${search}'" style="width:25px;height:25px;">${i}</button></c:if></c:forEach></c:if><c:if test="${pageIndex<totalPage }"><button onclick="window.location.href='textShow?pageIndex=${pageIndex+1}&categoryId=${categoryId }&search=${search}'">下一页</button><button onclick="window.location.href='textShow?pageIndex=${totalPage}&categoryId=${categoryId }&search=${search}'" style="width:50px;height:25px;" >末页</button></c:if>&nbsp;&nbsp;&nbsp;  <span style="color:orange;">${pageIndex }</span>/${totalPage}<!-- <div style="float:right;">`<form action="#" mehtod="get"><select id="goto" name="goto" ><option value="5">5</option><option value="10">10</option><option value="20">20</option> <input type="submit" value="goto"></form></div> --></td></tr></tbody></table></div><!--  引入尾部--><jsp:include page="foot.jsp"></jsp:include></body>
</html>

首页面后台是重点，前端分页是重点。

3.首页面样式
textList.css

@CHARSET "UTF-8";
/*--Author:Meice
2018年1月1日 下午4:02:50*//* 搜索框样式 */
#search{
/*  border:1px solid red; */width:450px;height:80px;margin: -70px 0px 0px 600px;}/*  登录信息样式*/
#userInfo{/* border: 1px solid red; */width: 200px;height: 60px;margin: -100px 0px 0px 1280px;
}/* 栏目样式 */
#category{/* border:1px solid red; */width:200px;height:300px;margin: 60px 0px 0px 70px;
}/* 帖子列表样式 */
#textList{/* border:1px solid red; */width:1200px;height:700px;margin: -300px 0px 0px 700px;float:right;
}/*
去除a 标签下划线*/a{text-decoration:none;/* 因为是蓝色字体，所以 */color:black;}/*设置li标签样式  */#category ul li{list-style:none;margin:15px;background-color: rgb(233,248,230);height:35px;width:100px;font-weight:bolder;}/* 登录信息字体样式  */
.userInfo{color:white;font-weight:bolder;font-size:15px;}

4. 后端代码
因为搜索、分栏、及首页都是在同一个页面展示，而且有分页，尤其是分页的时候，点击要去调用一个Servlet，所以最好的处理方式是按照接收的参数（栏目Id，搜索内容）来确定调用不同的方法，但是用一个Servlet来写。

TextShowDao
TextShowDaoImpl

TextShowService
TextShowServiceImpl

TextShowServlet
TextSearchServlet

TextShowDao

package com.hmc.dao;import java.util.List;import com.hmc.pojo.Category;
import com.hmc.pojo.TextAll;
import com.hmc.pojo.TextShow;
import com.hmc.pojo.User;
import com.hmc.pojo.UserInfo;/**
*
*2018年1月1日
*User:Meice
*上午10:59:20
*/
public interface TextShowDao {//1.查询首页帖子方法List<TextShow> listText (String sql,Object... params);//2.根据帖子Id返回整个user对象User listUser(int textId);//3.根据帖子Id，首页显示个人中心List<UserInfo> listUserInfo(String sql,Object... params);//4.帖子详情显示方法List<TextAll> listAll(String sql,Object... params);
}

TextShowDaoImpl

package com.hmc.dao;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;import com.hmc.pojo.Category;
import com.hmc.pojo.Reply;
import com.hmc.pojo.Text;
import com.hmc.pojo.TextAll;
import com.hmc.pojo.TextShow;
import com.hmc.pojo.User;
import com.hmc.pojo.UserInfo;
import com.hmc.util.DBUtil;
import com.hmc.util.GetPreparedStatementUtil;
import com.mysql.cj.api.xdevapi.Result;/**
*
*2018年1月1日
*User:Meice
*上午11:00:23
*/
public class TextShowDaoImpl implements TextShowDao {//1.返回首页帖子列表@Overridepublic List<TextShow> listText(String sql, Object... params) {Connection conn = DBUtil.getConn();PreparedStatement ps = null;ResultSet rs = null;ps = GetPreparedStatementUtil.getPs(conn, ps, sql, params);List<TextShow> listText = new ArrayList<>();//执行查询try {rs =    ps.executeQuery();while(rs != null && rs.next()) {TextShow ts = new TextShow();int textId = rs.getInt("textId");String title = rs.getString("title");//根据textId获取整个用户对象//select userId from text where textId = ?int replyCount = rs.getInt("replyCount");String textTime = rs.getString("textTime");User user = listUser(textId);//System.out.println("第一个user对象 "+user);ts.setTextId(textId);ts.setTitle(title);ts.setUser(user);ts.setReplyCount(replyCount);ts.setTextTime(textTime);listText.add(ts);}return listText;} catch (SQLException e) {e.printStackTrace();}finally {DBUtil.closeConn(conn, ps, rs);}return null;}//2.根据帖子Id返回整个user对象@Overridepublic User listUser(int textId) {Connection conn = DBUtil.getConn();PreparedStatement ps = null;ResultSet rs2 = null;List<User> listUser = new ArrayList<>();String sql = "select userId from text where textId = ?";Object[] params = {textId};PreparedStatement   ps2 = GetPreparedStatementUtil.getPs(conn, ps, sql, params);try {rs2 =  ps2.executeQuery();int userId =0;if(rs2!= null && rs2.next()) {userId =    rs2.getInt("userId");}//根据userId，返回对象UserLoginDao uld = new UserLoginDaoImpl();String sql2 = "select * from user where userId = ?";Object[] params2 = {userId};List<User> listUser2 =  uld.listUser(sql2, params2);return listUser2.get(0);} catch (SQLException e) {e.printStackTrace();}finally {DBUtil.closeConn(conn, ps2, rs2);}return null;}//3.根据帖子Id，展示个人中心@Overridepublic List<UserInfo> listUserInfo(String sql, Object... params) {Connection conn = DBUtil.getConn();List<UserInfo> list = new ArrayList<>();PreparedStatement ps = null;PreparedStatement ps3 = GetPreparedStatementUtil.getPs(conn, ps, sql, params);try {ResultSet rs3 = ps3.executeQuery();while(rs3!= null && rs3.next()) {UserInfo ui = new UserInfo();Text text = new Text();text.setTextId(rs3.getInt("textId"));text.setTitle(rs3.getString("title"));text.setContext(rs3.getString("context"));text.setTextTime(rs3.getString("textTime"));text.setUserId(rs3.getInt("userId"));Category category = new Category();category.setCategoryId(rs3.getInt("categoryId"));category.setCategoryName(rs3.getString("categoryName"));ui.setText(text);ui.setCategory(category);list.add(ui);}return list;    } catch (SQLException e) {e.printStackTrace();}finally {DBUtil.closeConn(conn, ps3, null);}return null;}//4.显示帖子详情，四表联查@Overridepublic List<TextAll> listAll(String sql, Object... params) {Connection conn = DBUtil.getConn();List<TextAll> listAll = new ArrayList<>();System.out.println("进来了...");PreparedStatement ps = null;PreparedStatement ps4 = GetPreparedStatementUtil.getPs(conn, ps, sql, params);try {ResultSet rs4 = ps4.executeQuery();while(rs4 != null && rs4.next()) {TextAll ta = new TextAll();Text text = new Text();text.setTextId(rs4.getInt("textId"));text.setTitle(rs4.getString("title"));text.setContext(rs4.getString("context"));text.setTextTime(rs4.getString("textTime"));text.setUserId(rs4.getInt("userId"));text.setCategoryId(rs4.getInt("categoryId"));User user = new User();user.setUserId(rs4.getInt("userId"));//text.setUserId(user.getUserId()); //据说，这样会导致hashCode()重复调用，导致内存溢出！user.setUserName(rs4.getString("userName"));user.setUserNick(rs4.getString("userNick"));user.setLoginTime(rs4.getString("loginTime"));user.setRegisterTime(rs4.getString("registerTime"));Category category = new Category();category.setCategoryId(rs4.getInt("categoryId"));//text.setCategoryId(category.getCategoryId());category.setCategoryName(rs4.getString("categoryName"));Reply reply = new Reply();reply.setReplyId(rs4.getInt("replyId"));reply.setReplyContext(rs4.getString("replyContext"));reply.setReplyTime(rs4.getString("replyTime"));reply.setReplyCount(rs4.getInt("replyCount"));//reply.setTextId(text.getTextId());//reply.setUserId(user.getUserId());reply.setTextId(rs4.getInt("textId"));reply.setReplyCount(rs4.getInt("replyCount"));ta.setText(text);ta.setUser(user);ta.setCategory(category);ta.setReply(reply);listAll.add(ta);}return listAll;} catch (SQLException e) {e.printStackTrace();}finally {DBUtil.closeConn(conn, ps4, null);}return null;}//5.返回帖子总条目数public int getCountAll(String sql,Object... params) {int countAll = 0;//String sql = "select count(textId) countAll from text";Connection conn = DBUtil.getConn();PreparedStatement ps = null;ps = GetPreparedStatementUtil.getPs(conn, ps, sql, params);ResultSet rs = null;try {rs = ps.executeQuery();if(rs != null && rs.next()) {countAll = rs.getInt("countAll");}} catch (SQLException e) {e.printStackTrace();}finally {DBUtil.closeConn(conn, ps, rs);}return countAll;}}

代码有注释，就不在赘述。

TextShowService

package com.hmc.service;
/**
*
*2018年1月1日
*User:Meice
*上午10:58:08
*/import java.util.List;import com.hmc.pojo.Category;
import com.hmc.pojo.TextAll;
import com.hmc.pojo.TextShow;
import com.hmc.pojo.User;
import com.hmc.pojo.UserInfo;public interface TextShowService {//1.查询首页帖子方法List<TextShow> listText (String sql,Object... params);//2.根据帖子Id返回整个user对象User listUser(int textId);//3.根据帖子Id，返回整个Category对象  因为查，只有反射可以优化，只有把对象写固定List<UserInfo> listUserInfo(String sql,Object... params);//4.帖子详情显示方法List<TextAll> listAll(String sql,Object... params);}

TextShowServiceImpl

package com.hmc.service;import java.util.List;import com.hmc.dao.TextShowDaoImpl;
import com.hmc.pojo.Category;
import com.hmc.pojo.TextAll;
import com.hmc.pojo.TextShow;
import com.hmc.pojo.User;
import com.hmc.pojo.UserInfo;/**
*
*2018年1月1日
*User:Meice
*上午10:59:51
*/
public class TextShowServiceImpl implements TextShowService {//1.首页显示帖子@Overridepublic List<TextShow> listText(String sql, Object... params) {return new TextShowDaoImpl().listText(sql, params);}//2.根据textId返回user对象@Overridepublic User listUser(int textId) {return new TextShowDaoImpl().listUser(textId);}//3.根据帖子Id，个人中心显示内容@Overridepublic List<UserInfo> listUserInfo(String sql, Object... params) {return new TextShowDaoImpl().listUserInfo(sql, params);}//4.显示帖子详情（四表联查）@Overridepublic List<TextAll> listAll(String sql, Object... params) {return new TextShowDaoImpl().listAll(sql, params);}}

TextShowServlet

package com.hmc.controller;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hamcrest.core.Is;
import com.hmc.dao.TextShowDaoImpl;
import com.hmc.pojo.TextShow;
import com.hmc.service.TextShowService;
import com.hmc.service.TextShowServiceImpl;
import com.hmc.util.GetStrToInt;/**
*
*2018年1月1日
*User:Meice
*下午7:00:16
*/
public class TextShowServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {TextShowService tss = new TextShowServiceImpl();TextShowDaoImpl tsd = new TextShowDaoImpl();//1.接收参数//传递2个参数search 、 categoryId String search = req.getParameter("search");String categoryIdStr = req.getParameter("categoryId");int categoryId = GetStrToInt.getInt(categoryIdStr);System.out.println("search内容:"+search+"categoryId "+categoryId);//得到当前页pageIndex String pageIndexStr = req.getParameter("pageIndex");int pageIndex = GetStrToInt.getInt(pageIndexStr);/*** 分页* 分页五要素：* countAll 总条目数* pageSize 每页显示数目* totalPage 总页数 （countAll /pageSize）* pageIndex 当前页* offset 偏移量，从第几条数据开始显示，也就是limit ?  (pageindex-1)*pageSize*/int countAll =0;//查首页帖子总条目数String sqlCountAll = "select count(textId) countAll from text";countAll = new TextShowDaoImpl().getCountAll(sqlCountAll, null);int pageSize = 20;int totalPage =(int)Math.ceil((double) countAll/pageSize);System.out.println("总页数："+totalPage);if(pageIndex ==0) {pageIndex = 1;}//页面传int offset  = (pageIndex-1)*pageSize;//limit offset,pageSize;//2.调用方法//定义全局的List<TextShow> textList 不论首页、搜索 、栏目都用同一个。分页只用做一次List<TextShow> textList = null;//执行首页查询方法if( search !=null && categoryId ==0) {//这是多余的判断/*if(search.equals("")) {search = "";}*///TODO  调用模糊查询方法System.out.println("调用模糊查询方法.....模糊查询进来了。。。。。。");String sqlSearch = "  select a.textId,a.title,a.userId,b.replyCount,a.textTime from (select t.textId,t.title,t.userId,t.textTime from text t left join user u on t.textId = u.userId) a "+ "left join (select r.textId, count(r.replyId) replyCount from reply  r group by textId) b "+ "on a.textId = b.textId where a.title like ? order by a.textId desc limit ?,?";System.out.println(sqlSearch);System.out.println("search内容："+search);Object[] paramsSearch = {"%"+search+"%",offset,pageSize};textList = tss.listText(sqlSearch, paramsSearch);System.out.println("模糊查询结果："+textList);System.out.println("模糊查询textList大小："+textList.size());//改变总页数String sqlSearchCountAll = "select count(textId) countAll from text where title like ?";Object[] paramsSearchCountAll = {"%"+search+"%"};if(textList != null) {countAll = tsd.getCountAll(sqlSearchCountAll, paramsSearchCountAll);}totalPage =(int)Math.ceil((double) countAll/pageSize);System.out.println("模糊查询总页数:"+totalPage);}if(categoryId != 0) {//TODO 调用分栏目查询//如果在栏目下查询if(search != null &&!search.equals("")) {String sqlSearchByCategoryId = "select a.textId,a.title,a.userId,a.categoryId,b.replyCount,a.textTime \r\n" + "               from \r\n" + "               (select t.textId,t.title,t.userId,t.textTime,t.categoryId from text t left join user u on t.textId = u.userId) a\r\n" + "               left join  \r\n" + "               (select r.textId, count(r.replyId) replyCount from reply  r group by textId) b\r\n" + "               on \r\n" + "               a.textId = b.textId \r\n" + "               where a.categoryId = ? and a.title like ?\r\n" + "               order by \r\n" + "               a.textId desc \r\n" + "               limit ?,?";Object[] paramsSearchByCategoryId = {categoryId,"%"+search+"%",offset,pageSize};textList = tss.listText(sqlSearchByCategoryId, paramsSearchByCategoryId);//分栏目在查询总条目数String sqlSearchByCategoryIdCountAll = "select count(textId) countAll from text where title like ? and categoryId = ?";Object[] paramsSearchByCategoryIdCountAll = {"%"+search+"%",categoryId};countAll = tsd.getCountAll(sqlSearchByCategoryIdCountAll, paramsSearchByCategoryIdCountAll);totalPage = (int)Math.ceil((double) countAll/pageSize);}else {System.out.println("分栏查询进来了。。。。。。。");String sqlCategory = " select a.textId,a.title,a.userId,a.categoryId,b.replyCount,a.textTime \r\n" + "               from \r\n" + "               (select t.textId,t.title,t.userId,t.textTime,t.categoryId from text t left join user u on t.textId = u.userId) a\r\n" + "               left join  \r\n" + "               (select r.textId, count(r.replyId) replyCount from reply  r group by textId) b\r\n" + "               on \r\n" + "               a.textId = b.textId \r\n" + "               where a.categoryId = ?\r\n" + "               order by \r\n" + "               a.textId desc \r\n" + "               limit ?,?";Object[] paramsCategory = {categoryId,offset,pageSize};textList =  tss.listText(sqlCategory, paramsCategory);//变化总页数String sqlCategoryCountAll = "select count(textId) countAll from text where categoryId = ?";Object[] paramsCategoryCountAll = {categoryId};countAll = tsd.getCountAll(sqlCategoryCountAll, paramsCategoryCountAll);totalPage =(int)Math.ceil((double) countAll/pageSize);}}//其他情况全部调用首页查询if(search == null  && categoryId ==0) {String sql = "select a.textId,a.title,a.userId,b.replyCount,a.textTime from (select t.textId,t.title,t.userId,t.textTime from text t left join user u on t.textId = u.userId) a left join  (select r.textId, count(r.replyId) replyCount from reply  r group by textId) b on a.textId = b.textId "+ "order by a.textId desc limit ?,?";Object[] params = {offset,pageSize};textList =  tss.listText(sql, params);System.out.println("textList大小："+textList.size());System.out.println(textList);}//当search categoryId 都有值的时候，怎么办？？/*  if(categoryId != 0 && search != null &&! search.equals("")) {System.out.println("执行在分栏中搜索的方法。。。。");}*///3，传值及页面跳转System.out.println("实际传过去总条目数:"+countAll);req.setAttribute("textList", textList);req.setAttribute("countAll", countAll);req.setAttribute("pageSize", pageSize);req.setAttribute("totalPage", totalPage);req.setAttribute("pageIndex", pageIndex);//传过去search categoryId便于点击分页的时候，调用不同的方法  否则永远调用textShowreq.setAttribute("search", search);req.setAttribute("categoryId", categoryId);req.getRequestDispatcher("index.jsp").forward(req, resp);}
}

TextSearchServlet

package com.hmc.controller;import java.io.IOException;
import java.util.List;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.hmc.pojo.TextShow;
import com.hmc.service.TextShowService;
import com.hmc.service.TextShowServiceImpl;/**
*
*2018年1月7日
*User:Meice
*下午5:10:12
*/
public class TextSearchServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException ,IOException {//1.接收参数 search//传递1个参数searchString search = req.getParameter("search");//2.调用方法if(search != null) {if(search.equals("")) {search = "";}TextShowService tss = new TextShowServiceImpl();String sql = " select a.textId,a.title,a.userId,b.replyCount,a.textTime \r\n" + "               from \r\n" + "               (select t.textId,t.title,t.userId,t.textTime from text t left join user u on t.textId = u.userId) a\r\n" + "               left join  \r\n" + "               (select r.textId, count(r.replyId) replyCount from reply  r group by textId) b\r\n" + "               on \r\n" + "               a.textId = b.textId \r\n" + "               where a.title like ？\r\n" + "               order by \r\n" + "               a.textId desc \r\n" + "               limit ?,?";Object[] params = {};List<TextShow> textList =   tss.listText(sql, params);}//3.跳转页面};
}

哈哈，功能看起来不多，细节还是蛮多的。

呵呵呵，如果读者能坚持看到这里，那么我也就不用总结了。后面会专门发表一篇博客，来总结这个小项目。
下期预告：个人中心，再会！

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