数据库连接问题
package bean;
import java.sql.*;
import com.microsoft.jdbc.sqlserver.SQLServerDriver;
public class connDB {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
public connDB(){
try {
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
} catch (java.lang.ClassNotFoundException e) {
System.err.println(e.getMessage());
}
}
public ResultSet executeQuery(String sql) {
try {
conn = Drivermanager.getConnection("jdbc:microsoft:sqlserver://COMPANY-30B0942:1433;DatabaseName=图书管理系统;user=sa;password='');
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery(sql);
} catch (SQLException ex) {
System.err.println(ex.getMessage());
}
return rs;
}
public int executeUpdate(String sql) {
int result = 0;
try {
conn = Drivermanager.getConnection("jdbc:microsoft:sqlserver://COMPANY-30B0942:1433;DatabaseName=图书管理系统;user=sa;password='');
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
result = stmt.executeUpdate(sql);
} catch (SQLException ex) {
result = 0;
}
return result;
}
public int executeUpdate_id(String sql) {
int result = 0;
try {
conn = Drivermanager.getConnection("jdbc:microsoft:sqlserver://COMPANY-30B0942:1433;DatabaseName=图书管理系统;user=sa;password='');
stmt = conn.createStatement( ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
result = stmt.executeUpdate(sql);
String ID = "select @@identity as id";
rs = stmt.executeQuery(ID);
if (rs.next()) {
int autoID = rs.getInt("id");
result = autoID;
}
} catch (SQLException ex) {
result = 0;
}
return result;
}
public void close() {
try {
if (rs != null) rs.close();
} catch (Exception e) {
e.printStackTrace(System.err);
}
try{
if (stmt != null) stmt.close();
}catch(Exception e){
e.printStackTrace(System.err);
}
try{
if (conn != null){
conn.close();
}
}catch(Exception e){
e.printStackTrace(System.err);
}
}
}
编译时候的错误为,conn,stmt都有错误,不知道是什么错误,请大家帮我看看