没弄过count返回值请大家帮忙!ssh框架
大概意识是这样的 传一个参数获取count值 可是不知道应该怎么获取 以前都是返回的list 返回long不会弄了
下面代码有很多错误 获取不到执行过sql的返回值!!!
public Long getcount(String id) throws Exception {
String sql="select count(*) from EXAM_ROOM where EXAM_ROOM.STUDENTID='"+id+"'"; List list = this.exeQuery(sql,new EXAM_ROOMFORM());
System.out.println(list);
return (Long) list.get(0);
}
大概意识是这样的 传一个参数获取count值 可是不知道应该怎么获取 以前都是返回的list 返回long不会弄了
下面代码有很多错误 获取不到执行过sql的返回值!!!
public Long getcount(String id) throws Exception {
String sql="select count(*) from EXAM_ROOM where EXAM_ROOM.STUDENTID='"+id+"'"; List list = this.exeQuery(sql,new EXAM_ROOMFORM());
System.out.println(list);
return (Long) list.get(0);
}
就是java这部分 不知道怎么获取
String sql="select * from EXAM_ROOM where EXAM_ROOM.STUDENTID='"+id+"'"; List list = this.exeQuery(sql,new EXAM_ROOMFORM());
System.out.println(list);
return (Long) list.size();
}这样呢?如果同样没有结果,那么说明你的hql语句有问题
System.out.println(list);
这句话打印结果是什么样的?
public PreparedStatementCreator count(final EXAM_ROOM EXAM_STU)throws Exception{
PreparedStatementCreator prc =null;
prc=new PreparedStatementCreator() {
public PreparedStatement createPreparedStatement(Connection cn)
throws SQLException {
PreparedStatement ps = null;
final String sql="select count(*) from EXAM_ROOM where STUDENTID=?";
ps=cn.prepareStatement(sql);
ps.setLong(1,EXAM_STU.getEXAMROOM_ID());
return ps;
}
};
return prc;
}
这么写还是不对啊!!java.lang.NullPointerException
com.ddl.ec.model.EXAM_ROOM$5.createPreparedStatement(EXAM_ROOM.java:134)
异常org.springframework.jdbc.UncategorizedSQLException: PreparedStatementCallback; uncategorized SQLException for SQL []; SQL state [63000]; error code [3115]; ORA-03115: 不支持的网络数据类型或表示法
; nested exception is java.sql.SQLException: ORA-03115: 不支持的网络数据类型或表示法
PreparedStatementCreator prc =null;
prc=new PreparedStatementCreator() {
public PreparedStatement createPreparedStatement(Connection cn)
throws SQLException {
PreparedStatement ps = null;
final String sql="select count(*) from EXAM_ROOM where STUDENTID=?";
ps=cn.prepareStatement(sql);
ps.setLong(1,EXAM_STU.getSTUDENTID());
return ps;
}
};
return prc;
}红色部分是我改了以后有值 但是值不对啊 他返回一个36了 但是单独执行sql返回的是1啊