javaweb版本的答答租车系统（源代码一）

　　这是前面发表的javaweb版本答答租车系统的源代码，因为发表文章有字数限制以及还有功能没扩展出来，因此这里只是一部分，后面还会有文章继续发表的
好了，首先javaweb项目是需要操作数据库的，因此需要建立对应的表来存放对应的数据，这里是四个表分别对应保存不同的数据（因为是源代码，所以直接是建表SQL语句了）
这是car_user表用来存放用户信息的
CREATE TABLE car_user (id INT(10) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,username varchar(50) NOT NULL,password varchar(50) NOT NULL,sex varchar(10) NOT NULL,tel varchar(50) NOT NULL,email varchar(50) NOT NULL,competence varchar(100) NOT NULL)　　这是car_commodity表用来存放商品信息的
CREATE TABLE car_commodity(id INT(10) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,name varchar(50) NOT NULL,rent int(50) NOT NULL,manned int(50) NOT NULL,cargo int(50) NOT NULL,owner varchar(100) NOT NULL)　　这是car_bill表用来存放用户账单的
CREATE TABLE car_bill(id INT(10) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,userid int(10) NOT NULL,carid int(10) NOT NULL,quantity int(50) NOT NULL,totalrent double(100) NOT NULL,carstatus varchar(100) NOT NULL,ordernumber varchar(100) NOT NULL,cartime varchar(100) NOT NULL)　　这是car_account 表用来存放用户账户信息的
CREATE TABLE car_account (id INT(10) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,userid int(10) not null,money varchar(30) not null,let_frequency int(20) not null,out_frequency int(20) not null)　　数据库之后就是建立web项目CarSystem了，在项目中创建com.david包用来存放4个数据库对应的4个实体类，为了解决程序乱码问题这里创建com.david.code包用来存放CharacterEncodingFilter.java字符编码过滤器，创建com.david.dao包用来存放4个实体类对应的数据库操作类以及连接数据库文件ConnectSJK.java，最后创建com.david.servlet用来存放所有的Servlet。
这是用户实体类User
package com.david;/** * 用户实体类 * @author David */public class User { private Integer id; //用户id private String username; //用户名 private String password; //密码 private String sex; //性别 private String tel; //电话 private String email; //邮箱 private String competence; //权限 private Account account; //关联类 public User(){ super(); } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public String getTel() { return tel; } public void setTel(String tel) { this.tel = tel; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getCompetence() { return competence; } public void setCompetence(String competence) { this.competence = competence; } public Account getAccount() { return account; } public void setAccount(Account account) { this.account = account; } @Override public String toString() { return "User [id=" + id + ", username=" + username + ", password=" + password + ", sex=" + sex + ", tel=" + tel + ", email=" + email + ", competence=" + competence + ", account=" + account + "]"; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((account == null) ? 0 : account.hashCode()); result = prime * result + ((competence == null) ? 0 : competence.hashCode()); result = prime * result + ((email == null) ? 0 : email.hashCode()); result = prime * result + ((id == null) ? 0 : id.hashCode()); result = prime * result + ((password == null) ? 0 : password.hashCode()); result = prime * result + ((sex == null) ? 0 : sex.hashCode()); result = prime * result + ((tel == null) ? 0 : tel.hashCode()); result = prime * result + ((username == null) ? 0 : username.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; User other = (User) obj; if (account == null) { if (other.account != null) return false; } else if (!account.equals(other.account)) return false; if (competence == null) { if (other.competence != null) return false; } else if (!competence.equals(other.competence)) return false; if (email == null) { if (other.email != null) return false; } else if (!email.equals(other.email)) return false; if (id == null) { if (other.id != null) return false; } else if (!id.equals(other.id)) return false; if (password == null) { if (other.password != null) return false; } else if (!password.equals(other.password)) return false; if (sex == null) { if (other.sex != null) return false; } else if (!sex.equals(other.sex)) return false; if (tel == null) { if (other.tel != null) return false; } else if (!tel.equals(other.tel)) return false; if (username == null) { if (other.username != null) return false; } else if (!username.equals(other.username)) return false; return true; }}　　这是商品实体类Commodity
package com.david;/** * 商品实体类 * @author David */public class Commodity { private Integer id; //商品编号 private String name; //车名 private Integer rent; //租金 private Integer manned; //载人量 private Integer cargo; //载货量 private String owner; //车主 public Commodity(){ super(); } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getRent() { return rent; } public void setRent(Integer rent) { this.rent = rent; } public Integer getManned() { return manned; } public void setManned(Integer manned) { this.manned = manned; } public Integer getCargo() { return cargo; } public void setCargo(Integer cargo) { this.cargo = cargo; } public String getOwner() { return owner; } public void setOwner(String owner) { this.owner = owner; } @Override public String toString() { return "Commodity [id=" + id + ", name=" + name + ", rent=" + rent + ", manned=" + manned + ", cargo=" + cargo + ", owner=" + owner + "]"; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((cargo == null) ? 0 : cargo.hashCode()); result = prime * result + ((id == null) ? 0 : id.hashCode()); result = prime * result + ((manned == null) ? 0 : manned.hashCode()); result = prime * result + ((name == null) ? 0 : name.hashCode()); result = prime * result + ((owner == null) ? 0 : owner.hashCode()); result = prime * result + ((rent == null) ? 0 : rent.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; Commodity other = (Commodity) obj; if (cargo == null) { if (other.cargo != null) return false; } else if (!cargo.equals(other.cargo)) return false; if (id == null) { if (other.id != null) return false; } else if (!id.equals(other.id)) return false; if (manned == null) { if (other.manned != null) return false; } else if (!manned.equals(other.manned)) return false; if (name == null) { if (other.name != null) return false; } else if (!name.equals(other.name)) return false; if (owner == null) { if (other.owner != null) return false; } else if (!owner.equals(other.owner)) return false; if (rent == null) { if (other.rent != null) return false; } else if (!rent.equals(other.rent)) return false; return true; }}　　这是账单实体类Biil
package com.david;/** * 账单实体类 * @author David */public class Bill { private Integer id; //序号 private Integer userid; //用户id private Integer carid; //车id private Integer quantity; //租车数量 private Double totalrent; //总租金 private String carstatus; //租车状态 private String cartime; //租车时间 private String ordernumber; //账单编号 private User user; public Bill(){ super(); } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public Integer getUserid() { return userid; } public void setUserid(Integer userid) { this.userid = userid; } public Integer getCarid() { return carid; } public void setCarid(Integer carid) { this.carid = carid; } public Integer getQuantity() { return quantity; } public void setQuantity(Integer quantity) { this.quantity = quantity; } public Double getTotalrent() { return totalrent; } public void setTotalrent(Double totalrent) { this.totalrent = totalrent; } public String getCarstatus() { return carstatus; } public void setCarstatus(String carstatus) { this.carstatus = carstatus; } public String getCartime() { return cartime; } public void setCartime(String cartime) { this.cartime = cartime; } public String getOrdernumber() { return ordernumber; } public void setOrdernumber(String ordernumber) { this.ordernumber = ordernumber; } public User getUser() { return user; } public void setUser(User user) { this.user = user; } @Override public String toString() { return "Bill [id=" + id + ", userid=" + userid + ", carid=" + carid + ", quantity=" + quantity + ", totalrent=" + totalrent + ", carstatus=" + carstatus + ", cartime=" + cartime + ", ordernumber=" + ordernumber + "]"; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((carid == null) ? 0 : carid.hashCode()); result = prime * result + ((carstatus == null) ? 0 : carstatus.hashCode()); result = prime * result + ((cartime == null) ? 0 : cartime.hashCode()); result = prime * result + ((id == null) ? 0 : id.hashCode()); result = prime * result + ((ordernumber == null) ? 0 : ordernumber.hashCode()); result = prime * result + ((quantity == null) ? 0 : quantity.hashCode()); result = prime * result + ((totalrent == null) ? 0 : totalrent.hashCode()); result = prime * result + ((userid == null) ? 0 : userid.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; Bill other = (Bill) obj; if (carid == null) { if (other.carid != null) return false; } else if (!carid.equals(other.carid)) return false; if (carstatus == null) { if (other.carstatus != null) return false; } else if (!carstatus.equals(other.carstatus)) return false; if (cartime == null) { if (other.cartime != null) return false; } else if (!cartime.equals(other.cartime)) return false; if (id == null) { if (other.id != null) return false; } else if (!id.equals(other.id)) return false; if (ordernumber == null) { if (other.ordernumber != null) return false; } else if (!ordernumber.equals(other.ordernumber)) return false; if (quantity == null) { if (other.quantity != null) return false; } else if (!quantity.equals(other.quantity)) return false; if (totalrent == null) { if (other.totalrent != null) return false; } else if (!totalrent.equals(other.totalrent)) return false; if (userid == null) { if (other.userid != null) return false; } else if (!userid.equals(other.userid)) return false; return true; }}　　这是账户实体类Account
package com.david;/** * 账户实体类 * @author David */public class Account { private Integer id; //账户编号 private Integer userid; //用户id private Double money; //账户余额 private Integer let_frequency; //租车次数 private Integer out_frequency; //出租次数 public Account(){ super(); } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public Integer getUserid() { return userid; } public void setUserid(Integer userid) { this.userid = userid; } public Double getMoney() { return money; } public void setMoney(Double money) { this.money = money; } public Integer getLet_frequency() { return let_frequency; } public void setLet_frequency(Integer let_frequency) { this.let_frequency = let_frequency; } public Integer getOut_frequency() { return out_frequency; } public void setOut_frequency(Integer out_frequency) { this.out_frequency = out_frequency; } @Override public String toString() { return "Account [id=" + id + ", userid=" + userid + ", money=" + money + ", let_frequency=" + let_frequency + ", out_frequency=" + out_frequency + "]"; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((id == null) ? 0 : id.hashCode()); result = prime * result + ((let_frequency == null) ? 0 : let_frequency.hashCode()); result = prime * result + ((money == null) ? 0 : money.hashCode()); result = prime * result + ((out_frequency == null) ? 0 : out_frequency.hashCode()); result = prime * result + ((userid == null) ? 0 : userid.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; Account other = (Account) obj; if (id == null) { if (other.id != null) return false; } else if (!id.equals(other.id)) return false; if (let_frequency == null) { if (other.let_frequency != null) return false; } else if (!let_frequency.equals(other.let_frequency)) return false; if (money == null) { if (other.money != null) return false; } else if (!money.equals(other.money)) return false; if (out_frequency == null) { if (other.out_frequency != null) return false; } else if (!out_frequency.equals(other.out_frequency)) return false; if (userid == null) { if (other.userid != null) return false; } else if (!userid.equals(other.userid)) return false; return true; }}　　这是用户数据库操作类UserDao
package com.david.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import com.david.User;/** * 用户数据库操作类 * @author David */public class UserDao { /** * 新增用户 * @param User 用户 * @author David */ public void saveUser(User user){ //获取数据库连接Connection对象 Connection conn = ConnectSJK.getConnection(); String sql = "insert into car_user(username,password,sex,tel,email,competence) value (?,?,?,?,?,?)"; try { //获取preparedstatement对象 PreparedStatement ps = conn.prepareStatement(sql); //对sql语句占位符参数进行动态赋值 ps.setString(1, user.getUsername()); ps.setString(2, user.getPassword()); ps.setString(3, user.getSex()); ps.setString(4, user.getTel()); ps.setString(6, user.getEmail()); ps.setString(7, user.getCompetence()); //执行更新操作 ps.executeUpdate(); //释放此preparedstatement对象的数据库和JDBC资源 ps.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally{ //关闭数据库连接 ConnectSJK.closeConnection(conn); } } /** * 用户登录 * @param username 用户名 * @param passwrod 密码 * @author David * @return 用户对象 */ public User login(String username,String password){ //实例化一个对象 User user = new User(); //获取数据库连接Connection对象 Connection conn = ConnectSJK.getConnection(); //根据用户名和密码查询用户信息 String sql = "select * from car_user where username = ? and password = ?"; try { //获取preparedStatement对象 PreparedStatement ps = conn.prepareStatement(sql); //对sql语句的占位符参数进行动态赋值 ps.setString(1, username); ps.setString(2, password); //执行查询获取结果集 ResultSet rs = ps.executeQuery(); //判断结果集是否有效 if(rs.next()){ //对用户对象属性赋值 user.setId(rs.getInt("id")); user.setUsername(rs.getString("username")); user.setPassword(rs.getString("password")); user.setSex(rs.getString("sex")); user.setTel(rs.getString("tel")); user.setEmail(rs.getString("email")); user.setCompetence(rs.getString("competence")); } //释放此ResultSet对象的数据库和JDBC资源 rs.close(); //释放此preparedStatement对象的数据库和JDBC资源 ps.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally{ //关闭数据库连接 ConnectSJK.closeConnection(conn); } return user; } /** * 判断用户在数据库中是否存在 * @param username 用户名 * @author David * @return 布尔值 */ public boolean userIsExsit(String username){ //获取数据库连接Connection对象 Connection conn = ConnectSJK.getConnection(); //根据指定用户名查询用户信息 String sql = "select * from car_user where username=?"; try { //获取preparedstatement对象 PreparedStatement ps = conn.prepareStatement(sql); //对sql占位符参数进行动态赋值 ps.setString(1, username); //执行查询获取结果集 ResultSet rs = ps.executeQuery(); //判断结果集是否有效 if(!rs.next()){ //如果无效则证明可用 return true; } // 释放此 ResultSet 对象的数据库和 JDBC 资源 rs.close(); // 释放此 PreparedStatement 对象的数据库和 JDBC 资源 ps.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally{ //关闭数据库连接 ConnectSJK.closeConnection(conn); } return false; } /** * 修改资料 * @param user 用户 * @author David */ public void modifyUser(User user){ //获取数据库连接Connection对象 Connection conn = ConnectSJK.getConnection(); //插入修改资料的sql语句 String sql = "update car_user set sex=?,tel=?,email=? where username=?"; try { //获取preparedstatement对象 PreparedStatement ps = conn.prepareStatement(sql); //对用户对象进行赋值 ps.setString(1, user.getSex()); ps.setString(2, user.getTel()); ps.setString(3, user.getEmail()); ps.setString(4, user.getUsername()); //执行更新操作 ps.executeUpdate(); //释放此preparedstatement对象的数据库和JDBC资源 ps.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally{ //关闭数据库连接 ConnectSJK.closeConnection(conn); } } /** * 根据用户名查id * @param username 用户名 * @author David * @return 整数id */ public int userid(String username){ //定义变量保存用户id int userid = 0; //获取数据库连接Connection对象 Connection conn = ConnectSJK.getConnection(); //根据用户名查询用户id String sql = "select id from car_user where username=?"; try { //获取preparedstatement对象 PreparedStatement ps = conn.prepareStatement(sql); //对sql占位符参数进行动态赋值 ps.setString(1, username); //执行查询获取结果集 ResultSet rs = ps.executeQuery(); //判断结果集是否有效 if(rs.next()){ //将结果赋值给变量userid userid = rs.getInt("id"); } // 释放此 ResultSet 对象的数据库和 JDBC 资源 rs.close(); // 释放此 PreparedStatement 对象的数据库和 JDBC 资源 ps.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally{ //关闭数据库连接 ConnectSJK.closeConnection(conn); } return userid; }}　　因为有2W字数限制，后面的会在另一篇文章中继续更新的！

javaweb版本的答答租车系统 （源代码一）