JDBC 增删查改(2)

1// ==================== Program Description ==========================2// 程序名称：示例13-2: User.java3// 程序目的：创建一个用来操作用户信息的类4// ==============================================================5public class User 6{7 private String username;8 private String password;9 private String regDate;1011 // 获取用户名12 public String getUsername() {13 return username;14 }1516 // 设置用户名17 public void setUsername(String username) {18 this.username = username;19 }2021 // 获取用户密码22 public String getPassword() {23 return password;24 }2526 // 设置用户密码27 public void setPassword(String password) {28 this.password = password;29 }3031 // 获取用户注册时间32 public String getRegDate() {33 return regDate;34 }3536 // 设置用户注册时间37 public void setRegDate(String regDate) {38 this.regDate = regDate;39 }40} 

 

1// ==================== Program Description ==========================2// 程序名称：示例13-3: UserMgr.java3// 程序目的：利用JDBC对数据库进行增删查改操作4// ==============================================================5import java.sql.*;6import test.DBConnection;78public class UserMgr 9{10 // 向数据库中添加用户信息11 public boolean addUser(User user) 12 {13 // 构造SQL语句14 String sql = "insert into tbl_user (vcUsername, vcPassword,dtRegDate) values('" +15 user.getUsername() + "','" + user.getPassword() +"',getDate())";16 Statement stmt;17 Connection conn;18 try {19 // 获取数据库连接20 conn = DBConnection.getConnection();2122 // 创建Statement对象23 stmt = conn.createStatement();2425 // 执行SQL语句26 stmt.executeUpdate(sql);27 stmt.close();28 conn.close();2930 return true;31 } 32 catch (SQLException e) {33 System.out.println(e.getMessage());34 }3536 return false;37 }3839 // 删除数据库中某个用户的信息40 public boolean deleteUser(User user)41 {42 String sql="delete from tbl_user wherevcUsername="+"'"+user.getUsername()+"'";43 Connection conn;44 Statement stmt;4546 try {47 conn=DBConnection.getConnection();48 stmt=conn.createStatement();49 stmt.executeUpdate(sql);50 stmt.close();51 conn.close();5253 return true;54 }55 catch (SQLException e)56 {57 System.out.println(e.getMessage());58 }5960 return false;61 }6263 // 根据用户名查询数据库获取一个用户对象64 public User getUser( String username )65 {66 User user;67 String sql="select * from tbl_user where vcUsername='"+username+"'";68 Statement stmt;69 Connection conn;7071 try {72 conn= DBConnection.getConnection();73 stmt=conn.createStatement();7475 // 执行SQL语句并将查询结果放入结果集中76 ResultSet rs=stmt.executeQuery(sql);7778 // 将结果集中的数据取出放入User类的对象中79 if (rs.next())80 {81 user=new User();82 user.setUsername(rs.getString("vcUsername"));83 user.setPassword(rs.getString("vcPassword"));84 user.setRegDate(rs.getDate("dtRegDate").toString());85 stmt.close();86 conn.close();87 return user;88 }89 }90 catch (SQLException e)91 {92 System.out.println(e.getMessage());93 }9495 return null;96 }9798 // 通过验证密码鉴定用户的身份99 public int checkUser(User user)100 {101 User dbUser= getUser(user.getUsername());102 if (dbUser==null)103 return 0;104 else if (dbUser.getPassword().equals(user.getPassword()) )105 return 1;106 else return -1;107 }108109 // 修改数据库中某个用户的信息110 public boolean modifyUser(User user)111 {112 Connection conn;113 Statement stmt;114 String sql="update tbl_user set vcPassword='"+user.getPassword()+"' where 115 vcUsername='"+user.getUsername()+"'";116117 try {118 conn=DBConnection.getConnection();119 stmt=conn.createStatement();120 stmt.executeUpdate(sql);121 stmt.close();122 conn.close();123124 return true;125 }126 catch (SQLException e)127 {128 System.out.println(e.getMessage());129 }130131 return false;132 }133}