RsModel rm=new RsModel();
String uid=(String) rm.getValueAt(0, 0);
问什么每次又要报错
java.lang.NullPointerException啊。。
我一行一列那里有值的啊。。
求高手解答!!
String uid=(String) rm.getValueAt(0, 0);
问什么每次又要报错
java.lang.NullPointerException啊。。
我一行一列那里有值的啊。。
求高手解答!!
我把代码贴出来import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.Vector;import javax.swing.table.AbstractTableModel;import com.mhl.db.SqlHelper;public class RsModel extends AbstractTableModel{
Vector col;
Vector rows;
public void query(String sql,String[] data){
//初始化列
col=new Vector();
//初始化行
rows=new Vector();
SqlHelper sh=new SqlHelper();
ResultSet rs=sh.Query(sql, data);
try {
ResultSetMetaData rsmd=rs.getMetaData();
for (int i = 0; i < rsmd.getColumnCount(); i++) {
col.add(rsmd.getColumnName(i+1));
}
while(rs.next()){
Vector temp=new Vector();
for (int i = 0; i < rsmd.getColumnCount(); i++) {
temp.add(rs.getString(i+1));
}
rows.add(temp);
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}finally{
sh.close();
}
}
public void update(String sql,String[] data){
SqlHelper sh=null;
try {
sh=new SqlHelper();
sh.update(sql, data);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}finally{
sh.close();
}
}
@Override
public int getColumnCount() {
// TODO Auto-generated method stub
return this.col.size();
} @Override
public int getRowCount() {
// TODO Auto-generated method stub
return this.rows.size();
} @Override
public Object getValueAt(int rowIndex, int columnIndex) {
// TODO Auto-generated method stub
return ((Vector)this.rows.get(rowIndex)).get(columnIndex);
} @Override
public String getColumnName(int column) {
// TODO Auto-generated method stub
return this.col.get(column).toString();
}}
这是RsModel
RsModel rm=new RsModel();
String uid=(String) rm.getValueAt(0, 0);应该为String sql= "";
String[] data = null;
//初始化sql和data......................
RsModel rm=new RsModel();
query(sql, data);
String uid=(String) rm.getValueAt(0, 0);
此时才不会出现空指针错误