Question

JDBC查询语句，报空指针异常

public Computer findById(String id) throws Exception{
Connection conn=DBUtil.getConnection();
Computer c=null;
PreparedStatement prep=
conn.prepareStatement("select * from t_product where id=?");
prep.setString(1, id);
ResultSet res=prep.executeQuery();
while(res.next()){
c.setId(res.getInt("id"));
c.setModel(res.getString("model"));
c.setPicName(res.getString("picName"));
c.setDescPro(res.getString("descPro"));
c.setPrice(res.getDouble("price"));
}
return c;
}
}
//报错行数 c.setId(res.getInt("id"));
写错了吗？谢谢！

Answer 1

while(res.next()){    
    c=new Computer();
    c.setId(res.getInt("id"));
    c.setModel(res.getString("model"));
    c.setPicName(res.getString("picName"));
    c.setDescPro(res.getString("descPro"));
    c.setPrice(res.getDouble("price"));    
   }

Answer 2

将Computer c = null;改为Computer c = new Computer();即可

Answer 3

把你的代码贴出来

Answer 4

应该是数据类型不一致吧，看一下异常信息