Java对数据的增删改查

数据的增删改查"/>

Java对数据的增删改查

 【本代码未连接数据库，重启服务后数据会恢复到初始状态，添加的用户信息会临时存储在堆空间中】

目录

User.java

package com.web.entity;public class User {private int id;private String name;private int age;/*** sex:0,表示男* sex:1,表示女*/private int sex;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public int getSex() {return sex;}public void setSex(int sex) {this.sex = sex;}@Overridepublic String toString() {return "User [id=" + id + ", name=" + name + ", age=" + age + ", sex=" + sex + "]";}public User(int id, String name, int age, int sex) {this.id = id;this.name = name;this.age = age;this.sex = sex;}public User() {}}

AddInfoServlet.java【添加用户信息】

package com.web.servlet;import java.io.IOException;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 com.web.entity.User;
import com.web.utility.DataUtil;@WebServlet("/addInfo")
public class AddInfoServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");doPost(req, resp);}@Overridepublic void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");String name = req.getParameter("name");String age = req.getParameter("age");int AGE = 0;if (age != null && !"".equals(age)) {AGE = Integer.valueOf(age);}int sex = Integer.parseInt(req.getParameter("sex"));User user = new User(1, name, AGE, sex);/** User user = new User(1, name, AGE, sex); * 等价于* User user1 = new User();* user1.setName(name);* user1.setAge(AGE);* user1.setSex(sex);*/DataUtil.addUser(user);resp.sendRedirect(req.getContextPath() + "/userList");}}

AddSkipServlet.java【跳转到添加用户页面】

package com.web.servlet;import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;@WebServlet("/addSkip")
public class AddSkipServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");doPost(req, resp);}@Overridepublic void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");req.getRequestDispatcher("/WEB-INF/jsp/user/add.jsp").forward(req, resp);}}

DeleteServlet.java【删除用户信息】

package com.web.servlet;import java.io.IOException;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 com.web.utility.DataUtil;@WebServlet("/del")
public class DeleteServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overridepublic void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {int id = Integer.valueOf(req.getParameter("id"));DataUtil.del(id);resp.sendRedirect(req.getContextPath() + "/userList");}}

ShowServlet.java【查看单个用户信息】

package com.web.servlet;import java.io.IOException;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 com.web.entity.User;
import com.web.utility.DataUtil;@WebServlet("/show")
public class ShowServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overridepublic void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");int id = Integer.valueOf(req.getParameter("id"));User user = DataUtil.show(id);req.setAttribute("user", user);req.getRequestDispatcher("/WEB-INF/jsp/user/show.jsp").forward(req, resp);}}

UpdateInfoServlet.java【修改用户信息】

package com.web.servlet;import java.io.IOException;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 com.web.entity.User;
import com.web.utility.DataUtil;@WebServlet("/updateInfo")
public class UpdateInfoServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");doPost(req, resp);}@Overridepublic void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");int id = Integer.valueOf(req.getParameter("id"));String name = req.getParameter("name");int age = Integer.valueOf(req.getParameter("age"));int sex = Integer.parseInt(req.getParameter("sex"));User user = new User(id, name, age, sex);DataUtil.update(user);resp.sendRedirect(req.getContextPath() + "/userList");}}

UpdateSkipServlet.java【跳转到修改用户信息页面】

package com.web.servlet;import java.io.IOException;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 com.web.utility.DataUtil;@WebServlet("/updateSkip")
public class UpdateSkipServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");doPost(req, resp);}@Overridepublic void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");int id = Integer.valueOf(req.getParameter("id"));req.setAttribute("user", DataUtil.show(id));req.getRequestDispatcher("/WEB-INF/jsp/user/update.jsp").forward(req, resp);}}

UserListServlet.java【显示全部用户信息列表】

package com.web.servlet;import java.io.IOException;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 com.web.utility.DataUtil;@WebServlet("/userList")
public class UserListServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");doPost(req, resp);}@Overridepublic void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 输入数据乱码解决方案:使用request对象获取浏览器提交数据前,先设置字符集req.setCharacterEncoding("utf-8");// 输出数据乱码解决方案,使用request输出数据前,先设置字符集和内容类型resp.setCharacterEncoding("utf-8");resp.setContentType("text/html");req.setAttribute("user", DataUtil.getUsers());req.getRequestDispatcher("/WEB-INF/jsp/user/list.jsp").forward(req, resp);}}

DataUtil.java

package com.web.utility;import java.util.ArrayList;
import java.util.List;import com.web.entity.User;public class DataUtil {private static List<User> users = new ArrayList<User>();static {users.add(new User(1, "张三", 20, 1));users.add(new User(2, "李四", 11, 0));users.add(new User(3, "王五", 22, 1));users.add(new User(5, "赵六", 24, 1));users.add(new User(6, "孙七", 28, 0));users.add(new User(7, "小明", 18, 0));}public static void addUser(User user) {int len = users.size() + 1;user.setId(len);users.add(user);}public static void del(int id) {User user = null;for(User u : users) {if(u.getId() == id) {user = u;}}users.remove(user);}public static void update(User user) {int index = 0;for(User u : users) {if(u.getId() == user.getId()) {index = users.indexOf(u);}}users.remove(index);users.add(index, user);}public static User show(int id) {User user = null;for(User u : users) {if(u.getId() == id) {user = u;}}return user;}public static List<User> getUsers() {return users;}}

add.jsp【添加用户页面】

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>添加用户</title>
<style type="text/css">a{text-decoration: none;}
</style>
</head>
<body><form action="<%=request.getContextPath() %>/addInfo" method="post">姓名：<input type="text" name="name"><br>年龄：<input type="number" name="age"><br>性别：<input type="radio" name="sex" checked="checked" value="0">男<input type="radio" name="sex" value="1">女<br><input type="submit" value="提交"></form><a href="<%=request.getContextPath() %>/userList">返回列表页面</a>
</body>
</html>

list.jsp【显示全部用户页面】

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户列表</title>
<style type="text/css">a{text-decoration: none;}th,td{width: 160px;height: 30px;}
</style>
</head>
<body><%-- ${user } --%><h1>用户列表</h1><a href="<%=request.getContextPath() %>/addSkip">添加</a><hr><table border="1" style="text-align: center"><tr><th>ID</th><th>姓名</th><th>年龄</th><th>性别</th><th>操作</th></tr><%-- <tr><td>${user[0].id }</td><td>${user[0].name }</td><td>${user[0].age }</td><td>查看  修改  删除</td></tr> --%><c:forEach items="${user }" var="u" varStatus="st"><tr><%-- <td>${u.id }</td> --%><td>${st.index + 1 }</td><td>${u.name }</td><td>${u.age }</td><%-- <td>${u.sex }</td> --%><%-- <td><c:if test="${u.sex eq 0}">男</c:if><c:if test="${u.sex eq 1}">女</c:if></td> --%><!-- 或 --><td><c:choose><c:when test="${u.sex eq 0}">男</c:when><c:otherwise>女</c:otherwise></c:choose></td><td><a href="<%=request.getContextPath() %>/show?id=${u.id }">查看 </a> <a href="<%=request.getContextPath() %>/updateSkip?id=${u.id }">修改</a>  <a href="<%=request.getContextPath() %>/del?id=${u.id}">删除</a></td></tr></c:forEach></table>
</body>
</html>

show.jsp【查看显示单个用户页面】

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>查看用户信息</title>
<style type="text/css">a{text-decoration: none;}th,td{width: 160px;height: 30px;}
</style>
</head>
<body>User = ${user }<hr><table border="1" style="text-align: center"><tr><th>ID</th><th>姓名</th><th>年龄</th><th>性别</th></tr><tr><td>${user.id }</td><td>${user.name }</td><td>${user.age }</td><td>${user.sex }</td></tr></table><hr><a href="<%=request.getContextPath() %>/userList">返回</a>
</body>
</html>

update.jsp【修改用户页面】

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>添加用户</title>
<style type="text/css">a{text-decoration: none;}
</style>
</head>
<body><form action="<%=request.getContextPath() %>/updateInfo" method="post"><input type="hidden" name="id" value="${user.id }"><br>姓名：<input type="text" name="name" value="${user.name }"><br>年龄：<input type="number" name="age" value="${user.age }"><br>性别：<input type="radio" name="sex" value="0" ${user.sex eq 0 ? "checked=\"checked\"" : "" }>男<input type="radio" name="sex" value="1" ${user.sex eq 1 ? "checked=\"checked\"" : "" }>女<br><input type="submit" value="提交"></form><a href="<%=request.getContextPath() %>/userList">返回列表页面</a>
</body>
</html>

index.jsp【项目启动默认访问页面】

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
<style type="text/css">
a {text-decoration: none;
}
</style>
</head>
<body><h1>欢迎来到数据操作项目</h1><h3><a href="<%=request.getContextPath()%>/userList">列表页面</a></h3>
</body>
</html>

引入 jstl-1.2.jar 和 standard-1.1.2.jar 包是为了能使用JSTL标签（如：<c:forEach>，<c:choose>等）