Question

求救Java用传sql语句进行数据库查询出错

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class dataopen {
public void sqlopen(){
try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
Connection conn=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=nicedata","xx", "xxxx");
if(conn==null){System.out.println("数据加载失败");}
else{}

}catch (Exception ex){
System.out.println(ex.getMessage());
}
}
//查
public List<listtry> split(String sql) throws SQLException{
List<listtry> list=new ArrayList<listtry>();
Connection conn=DriverManager.getConnection("jdbc:sqlserver://JH2012:1433;DatabaseName=pubs","sa", "hack");
Statement stc=conn.createStatement();
ResultSet n=stc.executeQuery(sql);
while(n.next()){
listtry nn=new listtry();
nn.setsId(n.getString(1));
nn.setSname(n.getString(2));
nn.setSage(n.getString(3));
nn.setSsex(n.getString(4));
nn.setSquestion(n.getString(6));
nn.setSanser(n.getString(7));
nn.setSadreess(n.getString(5));
list.add(nn);
}
stc.close();
n.close();
conn.close();
return list;
}

public static void main(String[] args) throws SQLException {
dataopen nn=new dataopen();
nn.sqlopen();
List<listtry> list=nn.split("select * from stuInfo");
for(listtry au : list){
System.out.println(au.getSname()+"\t"+au.getsId());

}

}

}
执行的时候提示List<listtry> list=nn.split("select * from stuInfo");
Statement stc=conn.createStatement();

Answer 1

nn.sqlopen();执行通过了嘛？
如果通过了，希望你的dataopen类改造一下，把connection加载到静态变量里面去
private Connection conn ;
public void sqlopen(){
try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
conn=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=nicedata","xx", "xxxx");
if(conn==null){System.out.println("数据加载失败");}
else{}

}catch (Exception ex){
System.out.println(ex.getMessage());
}
}

在split中直接使用conn即可