Servlet的知识点大致讲完了，今天补充下与之相关的一些小知识，然后做一个完整的小例子。
一、MVC设计模式
1、MVC设计模式是什么？
在了解MVC之前，先聊聊Model1、Model2开发模式。
Model1开发模式中，使用jsp页面嵌套一些java代码、代码块，既处理请求，又处理数据，将java代码和html代码高度耦合在一起，对于后期的维护和拓展非常不便，这就是Model1开发模式。
Model2开发模式，引入了分层思想，即MVC模式，将代码进行了分层，降低了耦合度，方便后期的维护和扩展。
MVC模式，其中M是Model的缩写，表示模型，在应用中包含业务处理层和数据访问层。数据访问层主要是对数据库的一些操作的封装。业务处理层应用JavaBean构建， JavaBean主要是用作将从View层获取的数据和数据库的数据进行桥接。
V是View的缩写，表示视图，视图提供了可交互的用户界面，向用户显示模型数据，通常使用jsp和HTML搭建。
C是Controller的缩写，表示控制层，负责调度，是模型和视图的桥梁。
2、为什么要用MVC设计模式？
一是程序耦合度较低，方便修改和维护；二是可扩展性高，方便后期的业务扩展；三是可重用性高，可以重复使用已有的控制层，减少重复代码。
二、完整的CRUD
1、新建一个Maven项目，建好目录结构
项目结构使用了上面提到的MVC分层结构，如下图所示
2、配置web.xml和pom.xml文件
web.xml文件是配置servlet的，pom.xml是配置所需要的jar包。
<servlet> <servlet-name>servlet</servlet-name> <servlet-class>web.EmployeeServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>servlet</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping>
<dependencies> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.8</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> </dependencies>
3、连接数据库
先建库，再建表，然后插入原始数据。
CREATE TABLE employee( id varchar(36) NOT NULL, name varchar(50), gender varchar(4), birthday DATE, email varchar(20), salary varchar(20), remark varchar(200), PRIMARY KEY (`id`) )ENGINE=InnoDB DEFAULT CHARSET=utf8; insert into employee values ('5476cbc52c084d56a8d2492a372450a3','小川94','男','2000-05-25','1340059045@qq.com','10000','无');
编写DBUtil类，连接数据库
/** * 管理数据库连接 * @author 小川94 * @date 2018年6月11日 */ public class DBUtil { private static String user =""; private static String password = ""; private static String url = ""; private static String driver = ""; private static Connection conn = null; /** * 获取数据库连接 * @return Connection */ public static Connection getConnection(){ try{ // 读取配置文件 user = ConfigUtil.getConfigValue("jdbc.user"); password = ConfigUtil.getConfigValue("jdbc.password"); url = ConfigUtil.getConfigValue("jdbc.jdbcUrl"); driver = ConfigUtil.getConfigValue("jdbc.driverClass"); // 加载驱动 Class.forName(driver); conn = DriverManager.getConnection(url, user, password); }catch(Exception e){ System.out.println("数据库连接异常"); e.printStackTrace(); } return conn; } /** * 关闭数据库连接 * @param conn */ public static void closeConnection(Connection conn){ if(conn != null){ try{ conn.close(); }catch(SQLException e){ System.out.println("数据库关闭异常"); e.printStackTrace(); } } } }
其中使用了读取配置文件的ConfigUtil类
/** * 读取配置文件 * @author 小川94 * @date 2018年6月11日 */ public class ConfigUtil { public static String getConfigValue(String tagName) { String tagValue = null; Properties prop = new Properties(); try { ClassLoader classLoader = ConfigUtil.class.getClassLoader(); // 读取配置文件dbconfig.properties InputStream in = classLoader.getResourceAsStream("dbconfig.properties"); prop.load(in); // 加载属性列表 Iterator<String> it = prop.stringPropertyNames().iterator(); while (it.hasNext()) { if (it.next().equals(tagName)) { tagValue = prop.getProperty(tagName); } } in.close(); } catch (Exception e) { e.printStackTrace(); } return tagValue; } }
4、编写实体类
/** * 实体类 * @author 小川94 * @date 2018年6月11日 */ public class Employee { private String id; // 主键 private String name; // 姓名 private String gender; // 性别 private String email; // 邮箱 private String salary; // 薪水 private String remark; // 备注 private Date birthday; // 出生日期 public Employee(){ } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getSalary() { return salary; } public void setSalary(String salary) { this.salary = salary; } public String getRemark() { return remark; } public void setRemark(String remark) { this.remark = remark; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } /** * 重写toString方法，方便junit测试 */ @Override public String toString() { return "Employee [id=" + id + ", name=" + name + ", gender=" + gender + ", birthday=" + birthday +", salary=" + salary + ", email=" + email + ", remark=" + remark + "]"; } }
5、查询数据
查询数据功能，一是查询出所有数据，二是需要考虑页面的查询条件，需要两者结合考虑。
控制层使用了反射机制，使用一个Servlet处理多个请求，减少代码重复。
@Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 获取请求的URI地址信息 String url = request.getRequestURI(); // 截取其中的方法名 String methodName = url.substring(url.lastIndexOf("/")+1, url.lastIndexOf(".")); Method method = null; try { // 使用反射机制获取在本类中声明了的方法 method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class); // 执行方法 method.invoke(this, request, response); } catch (Exception e) { throw new RuntimeException("调用方法出错！"); } }
/** * 查询employee表中的所有数据 * @return List<Employee> 包含所有员工信息的list */ public List<Employee> queryAllEmployee(String name, String salary, String salary2) { Connection conn = null; List<Employee> employees = new ArrayList<Employee>(); try{ // 连接数据库 conn = DBUtil.getConnection(); if (StringUtil.isEmpty(conn)) { throw new Exception("数据库连接失败"); } // 编写sql语句 String sql = "SELECT * FROM EMPLOYEE"; String str = ""; if(StringUtil.isNotEmpty(name) || StringUtil.isNotEmpty(salary) || StringUtil.isNotEmpty(salary2)){ if(StringUtil.isNotEmpty(name)){ str = " WHERE NAME LIKE '%"+name+"%'"; } if(StringUtil.isNotEmpty(salary)){ if(str.length() == 0){ str = " WHERE SALARY > " + salary; }else{ str = str + " AND SALARY > " + salary; } } if(StringUtil.isNotEmpty(salary2)){ if(str.length() == 0){ str = " WHERE SALARY < " + salary2; }else{ str = str + " AND SALARY < " + salary2; } } } // 创建一个 PreparedStatement 对象，初始化sql语句 PreparedStatement ps = conn.prepareStatement(sql+str); // 获取执行sql语句后的结果集 ResultSet rs = ps.executeQuery(); Employee emp = null; // 遍历结果集，添加到list中 while (rs.next()) { emp = new Employee(); emp.setId(rs.getString("id")); emp.setName(rs.getString("name")); emp.setGender(rs.getString("gender")); emp.setEmail(rs.getString("email")); emp.setBirthday(rs.getDate("birthday")); emp.setRemark(rs.getString("remark")); emp.setSalary(rs.getString("salary")); employees.add(emp); } } catch (Exception e) { e.printStackTrace(); } finally { // 关闭数据库连接 if (StringUtil.isNotEmpty(conn)) { DBUtil.closeConnection(conn); } } return employees; }
编写控制层代码
private void queryEmp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { EmployeeDao dao = new EmployeeDao(); request.setCharacterEncoding("utf-8"); String name = request.getParameter("name"); String salary = request.getParameter("salary"); String salary2 = request.getParameter("salary2"); List<Employee> employees = dao.queryAllEmployee(name, salary, salary2); request.setAttribute("employees", employees); request.getRequestDispatcher("queryList.jsp").forward(request, response); }
6、新增数据
本质是提交表单数据到后台，通过Model层处理数据。
/** * 新增员工信息 * @param emp */ public int addEmployee(Employee emp){ if(StringUtil.isEmpty(emp)){ throw new RuntimeException("参数为空！"); } Connection conn = null; int result = 0; try{ conn = DBUtil.getConnection(); if(StringUtil.isEmpty(conn)){ throw new Exception("数据库连接失败！"); } String sql = "INSERT INTO EMPLOYEE VALUES (?,?,?,?,?,?,?) "; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, StringUtil.getUUID()); ps.setString(2, emp.getName()); ps.setString(3, emp.getGender()); ps.setDate(4, emp.getBirthday()); ps.setString(5, emp.getEmail()); ps.setString(6, emp.getSalary()); ps.setString(7, emp.getRemark()); result = ps.executeUpdate(); }catch(Exception e){ e.printStackTrace(); } finally { // 关闭数据库连接 if (StringUtil.isNotEmpty(conn)) { DBUtil.closeConnection(conn); } } return result; }
/** * 新增（修改）员工信息，根据id是否为空判断新增操作、修改操作 * @param request * @param response * @throws ServletException * @throws IOException */ private void addEmp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { EmployeeDao dao = new EmployeeDao(); request.setCharacterEncoding("utf-8"); Employee emp = new Employee(); String id = request.getParameter("id"); if (StringUtil.isEmpty(id) || "null".equals(id)) { try { emp.setId(StringUtil.getUUID()); emp.setName(request.getParameter("name")); emp.setGender(request.getParameter("gender")); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); java.util.Date date = sdf.parse(request.getParameter("birthday")); java.sql.Date birthday = new java.sql.Date(date.getTime()); emp.setBirthday(birthday); emp.setEmail(request.getParameter("email")); emp.setSalary(request.getParameter("salary")); emp.setRemark(request.getParameter("remark")); } catch (Exception e) { e.printStackTrace(); } dao.addEmployee(emp); response.sendRedirect("queryList.jsp"); } else { modifyEmpInfo(request, response); } }
7、修改数据
修改数据，我们共用了新增数据的jsp页面，使用了js方法来控制页面的数据展示和可修改性，同时后台需要对新增和修改的数据处理逻辑拆分。
/** * 根据员工信息id来修改相关内容 * @param id * @return */ public boolean modifyEmployeeById(Employee emp){ if(StringUtil.isEmpty(emp)){ throw new RuntimeException("参数为空！"); } Connection conn = null; boolean flag = false; try{ conn = DBUtil.getConnection(); if(StringUtil.isEmpty(conn)){ throw new Exception("数据库连接失败！"); } String sql = "UPDATE EMPLOYEE SET EMAIL=? , SALARY=? , REMARK=? WHERE ID=? "; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, emp.getEmail()); ps.setString(2, emp.getSalary()); ps.setString(3, emp.getRemark()); ps.setString(4, emp.getId()); int result = ps.executeUpdate(); if (result == 1) { flag = true; } } catch(Exception e) { e.printStackTrace(); } finally { // 关闭数据库连接 if (StringUtil.isNotEmpty(conn)) { DBUtil.closeConnection(conn); } } return flag; }
编写控制层代码
private void modifyEmpInfo(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ request.setCharacterEncoding("utf-8"); EmployeeDao dao = new EmployeeDao(); Employee emp = new Employee(); try{ emp.setId(request.getParameter("id")); emp.setName(request.getParameter("name")); emp.setGender(request.getParameter("gender")); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); java.util.Date date = sdf.parse(request.getParameter("birthday")); java.sql.Date birthday = new java.sql.Date(date.getTime()); emp.setBirthday(birthday); emp.setEmail(request.getParameter("email")); emp.setSalary(request.getParameter("salary")); emp.setRemark(request.getParameter("remark")); }catch(Exception e){ e.printStackTrace(); } boolean flag = dao.modifyEmployeeById(emp); if(!flag){ request.setAttribute("msg", "修改员工信息失败！"); request.getRequestDispatcher("error.jsp").forward(request, response); }else{ response.sendRedirect("queryList.jsp"); } }
8、删除数据
删除数据，我们需要拿到所要删除数据的id。
/** * 根据员工信息的id删除数据 * @param id * @return */ public boolean deleteEmployeeById(String id){ if(StringUtil.isEmpty(id)){ throw new RuntimeException("参数为空！"); } Connection conn = null; boolean flag = false; try{ conn = DBUtil.getConnection(); if(StringUtil.isEmpty(conn)){ throw new Exception("连接数据库失败！"); } String sql = "DELETE FROM EMPLOYEE WHERE ID = ?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, id); int result = ps.executeUpdate(); if(result == 1){ flag = true; } } catch (Exception e) { e.printStackTrace(); } finally { // 关闭数据库连接 if (StringUtil.isNotEmpty(conn)) { DBUtil.closeConnection(conn); } } return flag; }
编写控制层代码
private void deleteEmp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { EmployeeDao dao = new EmployeeDao(); request.setCharacterEncoding("utf-8"); String id = request.getParameter("id"); boolean flag = dao.deleteEmployeeById(id); if(!flag){ request.setAttribute("msg", "删除员工信息失败！"); request.getRequestDispatcher("error.jsp").forward(request, response); }else{ request.getRequestDispatcher("queryList.jsp").forward(request, response); } }
9、查看数据
查看数据的本质是将数据查询出来，回显到页面。
/** * 根据员工信息id查询完整员工信息 * @param id * @return */ public Employee queryEmpById(String id) { if (StringUtil.isEmpty(id)) { throw new RuntimeException("参数为空！"); } Connection conn = null; Employee emp = new Employee(); try { conn = DBUtil.getConnection(); if (StringUtil.isEmpty(conn)) { throw new RuntimeException("数据库连接失败！"); } String sql = "SELECT * FROM EMPLOYEE WHERE ID=?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, id); ResultSet rs = ps.executeQuery(); if(StringUtil.isEmpty(rs)){ throw new RuntimeException("查询信息失败！"); } while (rs.next()) { emp.setId(rs.getString("id")); emp.setName(rs.getString("name")); emp.setGender(rs.getString("gender")); emp.setEmail(rs.getString("email")); emp.setBirthday(rs.getDate("birthday")); emp.setRemark(rs.getString("remark")); emp.setSalary(rs.getString("salary")); } } catch (Exception e) { e.printStackTrace(); } finally { // 关闭数据库连接 if (StringUtil.isNotEmpty(conn)) { DBUtil.closeConnection(conn); } } return emp; }
编写控制层代码
private void queryEmpInfo(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { EmployeeDao dao = new EmployeeDao(); request.setCharacterEncoding("utf-8"); String id = request.getParameter("id"); Employee emp = dao.queryEmpById(id); request.getSession().setAttribute("Emp", emp); request.getRequestDispatcher("empInfo.jsp").forward(request, response); }
10、单元测试
使用Junit包，来完成相应的功能方法测试。
public class TestSample extends TestCase { private long startTime; private long endTime; @Before public void setUp() throws Exception { this.startTime= System.currentTimeMillis(); System.out.println("=========开始测试==========="); } @After public void tearDown() throws Exception { this.endTime = System.currentTimeMillis(); System.out.println("测试用时："+(endTime-startTime)); System.out.println("=========测试结束==========="); } /** * 测试数据库连接 */ @Test public void testDBConnection(){ Connection conn = DBUtil.getConnection(); if(StringUtil.isEmpty(conn)){ System.out.println("数据库连接失败！"); }else{ System.out.println("数据库连接成功！"); DBUtil.closeConnection(conn); } } /** * 测试EmployeeDao中的 queryAllEmployee 方法 */ @Test public void testQueryAllEmployee(){ EmployeeDao dao = new EmployeeDao(); List<Employee> list = dao.queryAllEmployee("张","",""); if(StringUtil.isEmpty(list)){ System.out.println("查询员工信息失败"); }else{ for(Employee emp : list){ System.out.println(emp.toString()); } } } /** * 测试EmployeeDao中的 addEmployee 方法 */ @Test public void testAddEmployee(){ EmployeeDao dao = new EmployeeDao(); Employee emp = new Employee(); emp.setId(StringUtil.getUUID()); emp.setName("张三"); emp.setGender("男"); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); try { java.util.Date d = sdf.parse("1987-09-23"); java.sql.Date birthday = new java.sql.Date(d.getTime()); emp.setBirthday(birthday); } catch (ParseException e) { e.printStackTrace(); } emp.setEmail("152612@qq.com"); emp.setSalary("10500"); emp.setRemark("新入职员工"); int result = dao.addEmployee(emp); if(result == 1){ System.out.println("新增成功"); }else{ System.out.println("新增失败"); } } /** * 测试EmployeeDao中的 deleteEmployeeById 方法 */ @Test public void testDeleteEmployeeById(){ EmployeeDao dao = new EmployeeDao(); String id = "8926a2e7-4cf1-4370-abdd-1141f8f6412d"; boolean flag = dao.deleteEmployeeById(id); if(!flag){ System.out.println("删除员工信息失败！"); }else{ System.out.println("删除成功！"); } } /** * 测试EmployeeDao中的 queryEmpById 方法 */ @Test public void testQueryEmpById(){ String id = "0a100fb2-a619-40b5-a667-dba96fae8b49"; EmployeeDao dao = new EmployeeDao(); Employee emp = dao.queryEmpById(id); System.out.println(emp.toString()); } }
11、编写View层
查询页面jsp编写
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="java.util.*,entity.*,dao.*" %> <!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>员工信息查询列表</title> <script type="text/javascript"> function searchList(){ var name = document.getElementById("name").value; var salary = document.getElementById("salary").value; var salary2 = document.getElementById("salary2").value; var url = "queryEmp.do"; var str = ""; if (name || salary || salary2) { if(name){ str = "?name=" + name + ""; } if(salary){ if(str.length == 0){ str = "?salary=" + salary + ""; }else{ str = str + "&salary=" + salary + ""; } } if(salary2){ if(str.length == 0){ str = "?salary2=" + salary2 + ""; }else{ str = str + "&salary2=" + salary2 + ""; } } } window.location.href = url+str; } function addEmp(){ window.location.href = "addEmp.jsp"; } function myreset(){ document.getElementById("name").value = ""; document.getElementById("salary").value = ""; document.getElementById("salary2").value = ""; } </script> </head> <body> <div style="height:100px;"> <div style=""> <div style="float:left;"> <span style="margin-left:150px;">姓名</span> <% String name = request.getParameter("name"); if(name == null || name == ""){ name = ""; } String salary = request.getParameter("salary"); if(salary == null || salary == ""){ salary = ""; } String salary2 = request.getParameter("salary2"); if(salary2 == null || salary2 == ""){ salary2 = ""; } %> <input id="name" style="150px;height:20px;" type="text" name="name" value="<%=name %>"> </div> <div style="float:left;"> <span style="margin-left:50px;">薪水</span> <input id="salary" style="120px;height:20px;" type="text" value="<%=salary %>" name="salary"> 至 <input id="salary2" style="120px;height:20px;" type="text" value="<%=salary2 %>" name="salary2"> </div> </div> <div style="margin-top:40px;" align="center"> <input style="height:30px;font-size:16px;margin-right:20px;" type="button" onclick="searchList()" value="查询"> <input style="height:30px;font-size:16px;margin-right:20px;" type="button" onclick="myreset()" value="重置"> <input style="height:30px;font-size:16px;" type="button" onclick="addEmp()" value="新增"> </div> </div> <div align="center"> <table onload="searchList()" cellpadding="0" cellspacing="0" border="1px black solid"> <thead> <tr style="height:40px;"> <th style="80px;text-align: center;">序号</th> <th style="120px;text-align: center;">姓名</th> <th style="100px;text-align: center;">性别</th> <th style="150px;text-align: center;">出生日期</th> <th style="120px;text-align: center;">薪水</th> <th style="180px;text-align: center;">邮箱</th> <th style="150px;text-align: center;">备注</th> <th style="150px;text-align: center;">操作</th> </tr> </thead> <tbody> <% List<Employee> employees = (List<Employee>)request.getAttribute("employees"); if(employees != null){ for(int i=0; i<employees.size(); i++){ Employee e = employees.get(i); %> <tr style="height:35px;"> <td style="text-align:center;"><%=i+1 %></td> <td style="text-align:center;"><a href="queryEmpInfo.do?id=<%=e.getId() %>" style="text-decoration:none;color:blue"><%=e.getName() %></a></td> <td style="text-align:center;"><%=e.getGender() %></td> <td style="text-align:center;"><%=e.getBirthday() %></td> <td style="text-align:center;"><%=e.getSalary() %></td> <td style="text-align:center;"><%=e.getEmail() %></td> <td style="text-align:center;"><%=e.getRemark() %></td> <td style="text-align:center;"> <a href="openModifyEmpInfo.do?id=<%=e.getId() %>" style="text-decoration:none;color:blue">修改</a> <a href="deleteEmp.do?id=<%=e.getId() %>" style="text-decoration:none;color:blue">删除</a> </td> </tr> <% } } %> </tbody> </table> </div> </body> </html>
新增（修改）jsp页面编写
<%@page import="jdk.nashorn.internal.runtime.Undefined"%> <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="java.util.*,java.text.*,entity.Employee" %> <!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>新增员工信息</title> </head> <body onload="myload()"> <% String id = request.getParameter("id"); Employee emp = (Employee)request.getSession().getAttribute("Emp"); String name = ""; String gender = ""; String birthday = ""; String email = ""; String salary = ""; String remark = ""; if (emp!= null) { name = emp.getName(); gender = emp.getGender(); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); if(emp.getBirthday() != null){ java.sql.Date d = emp.getBirthday(); java.util.Date date = new java.util.Date(d.getTime()); birthday = sdf.format(date); } email = emp.getEmail(); salary = emp.getSalary(); remark = emp.getRemark(); } %> <div style="padding-top: 60px;" align="center"> <form action="addEmp.do?id=<%=id %>" method="post"> <table cellpadding="0" cellspacing="0" border="1px black solid"> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">姓名 </td> <td style="400px;"> <input id="name" style="350px;height:20px;margin-left:10px;" type="text" name="name"> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">性别 </td> <td> <input id="boy" style="30px;height:20px;margin-left:10px;" type="radio" name="gender" value="男">男 <input id="gril" style="30px;height:20px;margin-left:10px;" type="radio" name="gender" value="女">女 </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">出生日期 </td> <td> <input id="birthday" style="height:20px;margin-left:10px;" type="date" name="birthday"> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">邮箱 </td> <td> <input id="email" style="350px;height:20px;margin-left:10px;" type="text" name="email"> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">薪水 </td> <td> <input id="salary" style="350px;height:20px;margin-left:10px;" type="text" name="salary"> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">备注 </td> <td> <textarea id="remark" style="margin:10px;" rows="6" cols="47" name="remark"></textarea> </td> </tr> </table> <div style="margin:20px;"> <input style="height:30px;font-size:16px;margin-right:20px;" type="submit" value="提交"/> <input style="height:30px;font-size:16px;" type="reset" value="重置"/> </div> </form> </div> <script type="text/javascript"> var idstr = "<%=id %>"; function myload() { if (idstr != null && idstr != undefined && idstr != "null") { document.getElementById("name").value = "<%=name %>"; var gender = "<%=gender %>"; if(gender == "男"){ document.getElementById("boy").checked = true; document.getElementById("girl").disabled = "disabled"; } else { document.getElementById("gril").checked = true; document.getElementById("boy").disabled = "disabled"; } document.getElementById("birthday").value = "<%=birthday %>"; document.getElementById("email").value = "<%=email %>"; document.getElementById("salary").value = "<%=salary %>"; document.getElementById("remark").value = "<%=remark %>"; // 设置只读 document.getElementById("name").readOnly = true; document.getElementById("gril").readOnly = true; document.getElementById("birthday").readOnly = true; } else { document.getElementById("name").readOnly = false; document.getElementById("boy").readOnly = false; document.getElementById("gril").readOnly = false; document.getElementById("birthday").readOnly = false; } } </script> </body> </html>
查看信息jsp页面编写
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="entity.Employee" %> <!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>员工信息</title> </head> <body> <jsp:useBean id="Emp" class="entity.Employee" scope="session"></jsp:useBean> <div style="padding-top: 60px;" align="center"> <form> <h4>员工信息</h4> <table cellpadding="0" cellspacing="0" border="1px black solid"> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">姓名 </td> <td style="300px;"> <jsp:getProperty property="name" name="Emp"/> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">性别 </td> <td style="300px;"> <jsp:getProperty property="gender" name="Emp"/> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">出生日期 </td> <td style="300px;"> <jsp:getProperty property="birthday" name="Emp"/> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">邮箱 </td> <td style="300px;"> <jsp:getProperty property="email" name="Emp"/> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">薪水 </td> <td style="300px;"> <jsp:getProperty property="salary" name="Emp"/> </td> </tr> <tr style="height:40px;"> <td style="font-size:18px;text-align: right;100px;">备注 </td> <td style="300px;"> <jsp:getProperty property="remark" name="Emp"/> </td> </tr> </table> <div style="margin:20px;"> <input style="height:30px;font-size:16px;margin-right:20px;" type="button" onclick="history.back()" value="返回"/> </div> </form> </div> </body> </html>
错误信息jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!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>错误提示信息</title> </head> <body> <h1 style="margin:200px;">:( 您的上一步操作发生了错误！ <br> 错误信息:<%=request.getParameter("msg") %> </h1> </body> </html>
三、测试
测试结果如下图所示，对于分页展示数据的问题，下次再单独处理。
文章首发于我的个人公众号：悦乐书。喜欢分享一路上听过的歌，看过的电影，读过的书，敲过的代码，深夜的沉思。期待你的关注！
公众号后台输入关键字“Java学习电子书”，即可获得12本Java学习相关的电子书资源，如果经济能力允许，还请支持图书作者的纸质正版书籍，创作不易。