一: 準備工作
1.首先將MySql的jar包導入項目文件中,在進行連接。(Build path--> Add)
2.寫好配置文件(dbinfo.properties)
3.
4.創建相應的類進行。
二:具體實現
1:登錄界面
public class DengLu {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("請輸入帳號:");
String name = sc.nextLine();
System.out.println("請輸入密碼:");
String pwd = sc.nextLine();
DoDengLu dl = new DoDengLu();
User user = dl.findUser(name, pwd);
if(user!=null)
{
System.out.print("welcome to "+user.getName());
}
else
System.out.print("輸入錯誤");
}
}
2.與數據庫實現交互
public class DoDengLu {
public User findUser(String name,String pwd)
{
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
User u =null;
try{
conn = DBUtils.getConnection();
String Sql = "select * from stu28 where NAme=? and password=?"; // 預編譯
stmt = conn.prepareStatement(Sql);
// 給問號賦值
stmt.setString(1,name);
stmt.setString(2,pwd);
// String sql ="select * from stu28 where Name = '"+name+"' AND PASsword = '"+pwd+"'";
// 這樣寫會導致SQL注入問題 就是後面 or '1'='1
rs = stmt.executeQuery();
if(rs.next())
{
u = new User();
u.setId(rs.getInt(1));
u.setName(rs.getString(2));
u.setPassword(rs.getString(3));
u.setEmail(rs.getString(4));
u.setBirthday(rs.getDate(5));
}
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
DBUtils.closeAll(rs, stmt, conn);
}
return u;
}
}
3.幫助工具
public class DBUtils {
private static String DriverClass;
private static String url;
private static String user;
private static String password;
// 靜態代碼塊 類只要加載,直接執行
// 就是將配置文件加載;
static{
ResourceBundle rb = ResourceBundle.getBundle("dbinfo");
// 進行賦值操作;
DriverClass = rb.getString("DriverClass");
url = rb.getString("url");
user = rb.getString("user");
password = rb.getString("password");
try {
Class.forName(DriverClass);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// 創建兩個方法: // yi :得到連接的方法
public static Connection getConnection() throws Exception{
return DriverManager.getConnection(url,user,password);
}
// 二 : 關閉資源
public static void closeAll(ResultSet rs,Statement stmt,Connection conn)
{
if(rs!=null)
{
try{
rs.close();
}
catch(Exception e){
e.printStackTrace();
}
}
if(stmt!=null)
{
try{
stmt.close();
}
catch(Exception e){
e.printStackTrace();
}
}
if(conn!=null)
{
try{
conn.close();
}
catch(Exception e){
e.printStackTrace();
}
}
}
}
4.用戶public class User {
private int id;
private String name;
private String password;
private String email;
private Date birthday;
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 String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
}
5.配置文件
// 根據自己修改 DriverClass = com.mysql.jdbc.Driver url = jdbc:mysql:///JDBC28 user = root password =root