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package
javatest;
import
java.sql.*;
public
class
DBconn
{ // 驱动程序名
final
String driver = "com.mysql.jdbc.Driver" ;
// URL指向要访问的数据库名test
// MySQL配置时的用户名
final
String user = "root" ;
// MySQL配置时的密码
final
String password = "root" ;
public
Connection conn = null ;
public
Statement statement= null ;
public
DBconn()
{
try
{
// 加载驱动程序
Class.forName(driver);
// 连续数据库
conn = DriverManager.getConnection(url, user, password);
statement = conn.createStatement();
// if(!conn.isClosed())
// System.out.println("Succeeded connecting to the Database!");
} catch (Exception e) {
}
}
public
void
DBcolse()
{
try
{
this .conn.close();
} catch (Exception e)
{
e.printStackTrace();
System.out.println( "数据库关闭失败!" );
}
}
} |
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DBconn db1= new
DBconn();
ResultSet rs = null ;
try {
System.out.println( "用户请求注册" );
out.println( "please input name" );
user_name =in.readLine().trim();
out.println( "please input password" );
user_password =in.readLine().trim();
} catch
(Exception e)
{
System.out.println(e);
}
try
{
String sql= "select * from user where name=‘" +user_name+ "‘" ;
rs = db1.statement.executeQuery(sql);
if (rs.next())
{
System.out.println(user_name+ "已经注册" );
out.println(user_name+ "已经注册" );
}
else
{
String sql_insert= "insert into user(name,password) values( ‘" + user_name+ "‘ , ‘" +user_password+ "‘ )" ;
System.out.println( db1.statement.executeUpdate(sql_insert));
System.out.println( "注册成功,成功添加了" +user_name+user_password);
out.println( "注册成功,成功添加了" +user_name+user_password);
}
}
catch
(Exception e)
{
System.out.println(e);
}
|
更新数据
String sql= "update unit set "+field_id+" =‘"+value+"‘ where
device_id="+device_id+" and
index_in_device="+unit_id+"";
out.println(sql);
DBconn db1=new
DBconn();
int
rs;
rs =
db1.statement.executeUpdate(sql);
System.out.println("updata number="+rs);