JAVA课程设计模块设计与编程示例.docx

“班级设置”模块设计与编程示例按照MVC设计模式【模型(model)视图(view)控制器(controller)】，每个模块逻辑上按三层结构（数据访问层，业务层，Web层）依次从左到右进行设计。下面是以“班级设置”模块为例介绍设计思路。数据访问层业务层表示层(Web)Dbconnection(数据库连接)ClassinfoServiceImp(业务处理对象)ClassinfoServlet(视图显示对象)数据接口：ClassinfoDao数据访问对象: ClassinfoImp数据访问层：用于与数据库的连接以及各种数据操作，包括增加、删除、查询、修改等。该部分主要包括数据库连接、数据实体接口、数据访问对象。其中“数据访问对象”是对“数据实体接口”的具体实现。例如，数据库连接对象(Dbconnection)主要定义了数据库的访问连接等方法；抽闲数据接口(ClassinfoDao)抽象地定义了操作“班级信息”的各种接口方法(增删查修)；而数据访问对象(ClassinfoImp)实现了ClassinfoDao接口中的所有方法，达到数据操作与访问的目的。业务层：用于业务数据的处理，主要通过“数据访问对象”(ClassinfoImp)中提供的各种数据操作，完成相应的“业务层”功能。例如，ClassinfoServiceImp(班级模块的业务处理对象)调用ClassinfoImp中的各种数据处理方法，以实现业务数据的处理。表示层：采用可视化的界面形式显示各种业务处理上的数据，它主要调用业务层中的ClassinfoServiceImp来完成数据的显示。该层模块通常使用Servlet技术来实现，以动态显示。例如：ClassinfoServlet(班级模块的视图显示对象)调用 ClassinfoServiceImp中的各种操作服务或方法，实现“表示层”功能。注意：该“学生成绩管理系统”中的每个模块都需要定义上述4种对象或文件(除Dbconnection外)。下面将以“班级设置”模块为例，详细介绍具体设计过程。第一步.因为每个模块都要连接数据库。所以编写一个Dbconnection.java公共类（只需写一次）。第二步.每一模块的功能都需要操作数据，可以将数据存取操作都存放在javabean之中。例如，本例是Classinfo.java第三步.首先编写抽象数据接口ClassinfoDao.java(代码如下所示)，然后编写该接口的实现对象-数据访问对象(Classinfoimp.java)。使用该接口的目的是为了让业务层与数据访问层分离。public interface ClassinfoDao void add(Classinfo classinfo);void delete(String classID);void uptate(String classID, String gradeID, String className);Classinfo find(String classID);List getAll();List fenyeList(int page);int findCount();第四步.编写业务层.业务层用于业务数据的处理并完成相应的“业务层”功能。本例中的业务层是ClassinfoServiceImp.java。业务层编写完后以提供web层调用。第五步.编写表示层(web层).表示层是采用可视化的界面形式显示各种业务处理上的数据，它主要调用业务层中的ClassinfoServiceImp来完成数据操作功能，如增加、删除、查询、修改等。本例Web层程序是ClassinfoServlet.java。下面是核心代码解释：因为在修改时要解决中文乱码问题，所以先设置request的编码格式。protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException request.setCharacterEncoding(UTF-8);String method= request.getParameter(method);if(method.equals(add)add(request,response);else if(method.equals(delete)delete(request,response);else if(method.equals(listall)listall(request,response);else if(method.equals(update)update(request,response);else if(method.equals(fenye)fenyelistall(request, response);在增删改查中稍有困难的是删除和修改在一块实现。主要代码如下。function CheckAll(elementsA, elementsB) for (i = 0; i elementsA.length; i+) elementsAi.checked = true;if (elementsB.checked = false) for (j = 0; j elementsA.length; j+) elementsAj.checked = false;/判断用户是否选择了要删除的记录，如果是，则提示“是否删除”；否则提示“请选择要删除的记录”function checkdel(delid, formname) var flag = false;for (i = 0; i delid.length; i+) if (delidi.checked) flag = true;break;if (!flag) alert(请选择要删除的记录！);return false; else if (confirm(确定要删除吗？) formname.submit();班级编号年级编号班级名称删除修改$c.classID$c.gradeID$c.className修改 全选/反选 删除$bar注：一个jsp里可以有多个表单。本例中还有一个值得学习的地方是把数据分页。用mysql和sqlserver数据库实现的方式是不同的。本例还有两个filter类。CheckLoginFilter.java是用来阻止没有登录的用户进入后台管理。后来发现一个问题，就是在登录后，然后退出，再在浏览器里访问main.jsp还是可以进入后台，然后创建一个Nocachefilter.java来阻止浏览器缓存。对于get方式，服务器端用Request.QueryString获取变量的值，对于post方式，服务器端用Request.Form获取提交的数据。附录：1. 数据库连接对象(Dbconnection.java)package stu.utils;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import org.junit.Test;public class Dbconnection protected static String dbClassName = com.microsoft.sqlserver.jdbc.SQLServerDriver;protected static String dbUrl = jdbc:sqlserver:/:1433;+ DatabaseName=DB_Student;protected static String dbUser = sa;protected static String dbPwd = 1234;public Connection connect = null;public Statement stmt=null;public ResultSet rs=null;Testpublic Connection getConnection() Connection conn = null;try if (conn = null) Class.forName(dbClassName).newInstance(); catch (Exception ee) /System.exit(0);try conn=DriverManager.getConnection(dbUrl,dbUser,dbPwd);if(conn=null)System.out.println(数据库名称错误);Statement st=conn.createStatement(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace(); System.out.println(数据库连接错误);return conn;public ResultSet executeQuery(String sql) try connect=getConnection();stmt=connect.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);rs=stmt.executeQuery(sql); catch (SQLException e) / TODO Auto-generated catch blockSystem.err.println(e.getMessage();e.printStackTrace();return rs;/执行添加public int executeUpdate(String sql)int result=0;try connect=getConnection();stmt=connect.createStatement();result=stmt.executeUpdate(sql);/System.out.print(添加成功); catch (SQLException e) / TODO Auto-generated catch block/e.printStackTrace();result=0;try stmt.close(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();return result;public void close()try if(rs!=null)rs.close(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();try if(stmt!=null)stmt.close(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();try if(connect!=null)connect.close(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();2. 数据实体JavaBean(Classinfo.java)package stu.domain;public class Classinfo public static final int PAGE_SIZE = 2;private String classID;private String gradeID;private String className;public String getClassID() return classID;public void setClassID(String classID) this.classID = classID;public String getGradeID() return gradeID;public void setGradeID(String gradeID) this.gradeID = gradeID;public String getClassName() return className;public void setClassName(String className) this.className = className;3. 抽象数据接口(ClassinfoDao.java)package stu.dao;import java.util.List;import stu.domain.Classinfo;public interface ClassinfoDao void add(Classinfo classinfo);void delete(String classID);void uptate(String classID, String gradeID, String className);Classinfo find(String classID);List getAll();List fenyeList(int page);int findCount();4. 数据访问层(Classinfoimp.java)：实现了ClassinfoDao接口package stu.dao.imp;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.ArrayList;import java.util.List;import stu.dao.ClassinfoDao;import stu.domain.Classinfo;import stu.domain.User;import stu.utils.Dbconnection;public class Classinfoimp implements ClassinfoDao public void add(Classinfo classinfo)Dbconnection conn=new Dbconnection();String sql=Insert into tb_classinfo values(+classinfo.getClassID()+,+classinfo.getGradeID()+,+classinfo.getClassName()+);conn.executeUpdate(sql);conn.close();public void delete(String classID) Dbconnection conn=new Dbconnection();String sql=delete tb_classinfo where classID=+classID+;conn.executeUpdate(sql);conn.close();public void uptate(String classID,String gradeID,String className)Dbconnection conn=new Dbconnection();String sql=update tb_classinfo set gradeID=+gradeID+,className=+className+where classID=+classID+;conn.executeUpdate(sql);conn.close();public Classinfo find(String classID)Classinfo cl=new Classinfo();Dbconnection conn=new Dbconnection();String sql=select * from tb_classinfo where classID=+classID+;ResultSet rs=conn.executeQuery(sql);try while(rs.next() cl.setClassID(rs.getString(1); cl.setGradeID(rs.getString(2); cl.setClassName(rs.getString(3); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();cl.setClassID(classID);return cl;public List getAll()Dbconnection conn=new Dbconnection();String sql=select * from tb_classinfo;ResultSet rs=conn.executeQuery(sql);List list=new ArrayList(); try while(rs.next() Classinfo cl=new Classinfo(); cl.setClassID(rs.getString(1); cl.setGradeID(rs.getString(2); cl.setClassName(rs.getString(3); list.add(cl); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();return list;/SELECT TOP 30 * FROM ARTICLE WHERE ID NOT IN(SELECT TOP 45000 ID FROM ARTICLE ORDER BY YEAR DESC, ID DESC) ORDER BY YEAR DESC,ID DESC public List fenyeList(int page)List list = new ArrayList();Dbconnection conn=new Dbconnection();String sql = select top +Classinfo.PAGE_SIZE+ * from tb_classinfo where classID not in(select top +(page - 1) * Classinfo.PAGE_SIZE+ classID from tb_classinfo order by classID desc) order by classID desc;try ResultSet rs=conn.executeQuery(sql);while(rs.next()Classinfo cl=new Classinfo();cl.setClassID(rs.getString(1);cl.setGradeID(rs.getString(2);cl.setClassName(rs.getString(3);list.add(cl);rs.close(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();return list;public int findCount()int count=0;Dbconnection Dbconn=new Dbconnection();Connection con=Dbconn.getConnection();String sql = select count(*) from tb_classinfo;try Statement stmt = con.createStatement();ResultSet rs = stmt.executeQuery(sql);if (rs.next() / 光标向后移动，并判断是否有效count = rs.getInt(1); / 对总记录数赋值rs.close(); / 关闭ResultSetcon.close(); / 关闭Connection catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();return count;5.数据处理业务类(ClassinfoServiceImp.java)package stu.service.imp;import java.util.List;import stu.dao.ClassinfoDao;import stu.dao.imp.Classinfoimp;import stu.domain.Classinfo;public class ClassinfoServiceImp private ClassinfoDao dao=new Classinfoimp();public void addClassinfo(Classinfo classinfo) dao.add(classinfo); public void deleteClassinfo(String classID) dao.delete(classID); public void uptateClassinfo(String classID,String gradeID,String className) dao.uptate(classID, gradeID, className); public Classinfo findClassinfo(String classID) return dao.find(classID); public List getAllClassinfo()return dao.getAll(); public List fenyeListClassinfo(int page)return dao.fenyeList(page); public int ClassinfofindCount() return dao.findCount();6. 视图显示模块(ClassinfoServlet.java)package stu.web.controller;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import stu.domain.Classinfo;import stu.service.imp.ClassinfoServiceImp;/* * Servlet implementation class ClassinfoServlet */WebServlet(/ClassinfoServlet)public class ClassinfoServlet extends HttpServlet private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException request.setCharacterEncoding(UTF-8);String method= request.getParameter(method);if(method.equals(add)add(request,response);else if(method.equals(delete)delete(request,response);else if(method.equals(listall)listall(request,response);else if(method.equals(update)update(request,response);else if(method.equals(fenye)fenyelistall(request, response);private void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException request.setCharacterEncoding(UTF-8);String classID=request.getParameter(classID);String gradeID=request.getParameter(gradeID);String className=request.getParameter(className);ClassinfoServiceImp service=new ClassinfoServiceImp();service.uptateClassinfo(classID, gradeID, className);listall(request, response);private void fenyelistall(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException request.setCharacterEncoding(UTF-8);int currPage = 1;if(request.getParameter(page) != null) / 判断传递页码是否有效currPage = Integer.parseInt(request.getParameter(page);/ 对当前页码赋值ClassinfoServiceImp service= new ClassinfoServiceImp();List Classinfos=service.fenyeListClassinfo(currPage);request.setAttribute(Classinfos, Classinfos);int pages ;int count = service.ClassinfofindCount();if(count % Classinfo.PAGE_SIZE=0)pages=count/Classinfo.PAGE_SIZE;elsepages=count/Classinfo.PAGE_SIZE+1;StringBuffer sb = new StringBuffer();if(currPage1)int c=currPage-1;sb.append( + 首页);sb.append();sb.append( + 上一页);sb.append();elsesb.append(首页);sb.append();sb.append(上一页);sb.append();for(int i=1;i=pages;i+)if(i=currPage)sb.append( + i + );elsesb.append( + i + );sb.append();if(currPagepages)int c=currPage+1;sb.append( + 下一页);sb.append();sb.append( + 尾页);sb.append();elsesb.append(下一页);sb.append();sb.append(尾页);sb.append();request.setAttribute(bar, sb.toString();request.getRequestDispatcher(/banjishezhi.jsp).forward(request, response);private void listall(HttpServletRequest request,HttpServletResponse response) ClassinfoServiceImp cs=new ClassinfoServiceImp();List Classinfos=cs.getAllClassinfo();request.setAttribute(Classinfos, Classinfos);try request.getRequestDispatcher(/banjishezhi.jsp).forward(request, response); catch (ServletException e) / TODO Auto-generated catch blocke.printStackTrace(); catch (IOException e) / TODO Auto-generated catch blocke.printStackTrace();private void delete(HttpServletRequest request, HttpServletResponse response) / TODO Auto-generated method stubString ID=request.getParam