@Permission("MySQL")
contract MySQLExample{
  @Description("连接MySQL，参数示例: {\"url\":"39.106.6.6:3306\",\"userName\":\"haiou\",\"pwd\":\"haiou\"}")
  export function connectDBAndQuery(args){
    args = JSON.parse(args);
    var conn = MySQLUtil.getConnection(args.url,args.userName,args.pwd);
    if (conn!=undefined && !conn.isClosed()){
      print("successfully connected");
    }
    else return "connect failed";
    var  sql = "select * from haiou.catering limit 0,10";
    var statement = conn.createStatement();
    var resultSet = statement.executeQuery(sql);
    ret  = [];
    var meta = resultSet.getMetaData();
    for (;resultSet.next();){
      var line = {
      };
      for (var j=1;j<=meta.getColumnCount();j++){
        line[meta.getColumnName(j)] = resultSet.getString(j);
      }
      ret.push(line);
    }
    return JSON.stringify(ret);
  }
}