我试图使用下面的代码插入临时表并选择它......当我运行它时，我得到一个 NullPointer 异常......不确定是什么问题......同样适用于 mysql 驱动程序......我在这两种情况下都使用 jdbc
package mysql.first;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class MSSqlAccess {
private Connection connect = null;
private Statement statement = null;
private PreparedStatement preparedStatement = null;
private int dmlresultSet = 0;
private ResultSet ddlresultSet = null;
/**
* @param args
*/
public static void main(String[] args) throws Exception {
MSSqlAccess dao = new MSSqlAccess();
//dao.readDataBase();
dao.createtemptable();
}
public void createtemptable() throws Exception{
try
{
// This will load the MySQL driver, each DB has its own driver
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
// Setup the connection with the DB
String db_connect_string = "jdbc:sqlserver://localhost";
String db_userid = "Test";
String db_password ="test";
Connection connect = DriverManager.getConnection(db_connect_string
,db_userid, db_password);
connect.setAutoCommit(false);
// Statements allow to issue SQL queries to the database
statement = connect.createStatement();
// Result set get the result of the SQL query
String sql = "CREATE TABLE #REGISTRATION " +
"(id INTEGER not NULL, " +
" first VARCHAR(255), " +
" last VARCHAR(255) )";
dmlresultSet = statement
.executeUpdate(sql);
System.out.println("Temp table created return code = " + dmlresultSet);
insertRows(1,"FNAME1","LNAME1");
selectRows();
insertRows(2,"FNAME2","LNAME2");
selectRows();
updateRows();
selectRows();
insertRows(3,"FNAME3","LNAME3");
}
catch (Exception e){
System.out.println("Error = " + e);
throw e;
} finally{
close();
}
}
private void insertRows(int id, String first, String last) throws SQLException {
System.out.println(id);
System.out.println(first);
System.out.println(last);
preparedStatement = connect
.prepareStatement("insert into REGISTRATION values (?, ?, ?)");
preparedStatement.setString(2, first);
preparedStatement.setString(3, last);
preparedStatement.setInt(1, id);
preparedStatement.executeUpdate();
}
private void selectRows() throws SQLException {
preparedStatement = connect
.prepareStatement("SELECT id, first, last from REGISTRATION");
ddlresultSet = preparedStatement.executeQuery();
writeResultSet(ddlresultSet);
}
private void updateRows() throws SQLException {
preparedStatement = connect
.prepareStatement("Update REGISTRATION set first = 'RENAMED' WHERE ID = 1");
dmlresultSet = preparedStatement.executeUpdate();
}
private void writeResultSet(ResultSet resultSet) throws SQLException {
System.out.println(" ");
System.out.println("***** Printing the Rows *****");
// ResultSet is initially before the first data set
while (resultSet.next()) {
// It is possible to get the columns via name
// also possible to get the columns via the column number
// which starts at 1
// e.g. resultSet.getSTring(2);
int id = resultSet.getInt("id");
String first = resultSet.getString("first");
String last = resultSet.getString("last");
System.out.println("ID: " + id);
System.out.println("First: " + first);
System.out.println("Last: " + last);
}
}
// You need to close the resultSet
private void close() {
try {
if (ddlresultSet != null) {
ddlresultSet.close();
}
if (statement != null) {
statement.close();
}
if (connect != null) {
connect.close();
}
} catch (Exception e) {
}
}
}