package mypackage;
import java.sql.*;
public class DB {
// ODBC方式连接数据库
String ACCDBDriver ="sun.jdbc.odbc.JdbcOdbcDriver";
String sConnStr = "jdbc:odbc:book";
Connection conn;
Statement stmt;
ResultSet rs;
public DB() {
try {
Class.forName(ACCDBDriver);
} catch (java.lang.ClassNotFoundException e) {
System.err.println("数据库驱动注册错误信息: " + e.getMessage());
}
}
// 执行SQL查询语句
public ResultSet executeQuery(String sql) {
rs = null;
try {
conn=DriverManager.getConnection(sConnStr);
stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
} catch (SQLException ex) {
System.err.println("执行SQL查询语句错误,错误信息:111111 " + ex.getMessage());
}
return rs;
}
执行结果报错
执行SQL查询语句错误,错误信息:111111 [Microsoft][ODBC Microsoft Access 驱动程序]非法地使用 null 指针
import java.sql.*;
public class DB {
// ODBC方式连接数据库
String ACCDBDriver ="sun.jdbc.odbc.JdbcOdbcDriver";
String sConnStr = "jdbc:odbc:book";
Connection conn;
Statement stmt;
ResultSet rs;
public DB() {
try {
Class.forName(ACCDBDriver);
} catch (java.lang.ClassNotFoundException e) {
System.err.println("数据库驱动注册错误信息: " + e.getMessage());
}
}
// 执行SQL查询语句
public ResultSet executeQuery(String sql) {
rs = null;
try {
conn=DriverManager.getConnection(sConnStr);
stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
} catch (SQLException ex) {
System.err.println("执行SQL查询语句错误,错误信息:111111 " + ex.getMessage());
}
return rs;
}
执行结果报错
执行SQL查询语句错误,错误信息:111111 [Microsoft][ODBC Microsoft Access 驱动程序]非法地使用 null 指针