java mysql 简单操作
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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);
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