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java该数据库代码 java连接数据库的代码放在main外面就报错

IT技术代码

java连接数据库的代码用这个类吧.好java该数据库代码的话,给java该数据库代码我加加分.
import java.sql.*;
/**
* @功能: 一个JDBCjava该数据库代码的本地化API连接类,封装java该数据库代码了数据操作方法,只用传一个SQL语句即可
* @作者: 李开欢
* @日期: 2007/
*/
public class ConnectionDemo {
/*
* 这里可以将常量全部放入另一个类中,以方便修改
*/
private static Connection conn;
private static Statement ps;
private static ResultSet rs;
private static final String DRIVER = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
private static final String URL = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=mydb";
private static final String USER ="sa";
private static final String PASS = "sa";
public ConnectionDemo() {
// TODO Auto-generated constructor stub
ConnectionDemo.getConnection();
}
public static Connection getConnection(){
System.out.println("连接中...");
try {
Class.forName(ConnectionDemo.DRIVER);
conn = DriverManager.getConnection(ConnectionDemo.URL, ConnectionDemo.USER, ConnectionDemo.PASS);
System.out.println("成功连接");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
publicstatic Statement getStatement(String sql){
System.out.println("执行SQL语句中...");
try {
ps = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
if(sql.substring(0, 6).equals("select")){
rs = ps.executeQuery(sql);
System.out.println("执行完查询操作,结果已返回ResultSet集合");
}else if(sql.substring(0, 6).equals("delete")){
ps.executeUpdate(sql);
System.out.println("已执行完毕删除操作");
}else if(sql.substring(0, 6).equals("insert")){
ps.executeUpdate(sql);
System.out.println("已执行完毕增加操作");
}else{
ps.executeUpdate(sql);
System.out.println("已执行完毕更新操作");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return ps;
}
public static ResultSet getResultSet(){
System.out.println("查询结果为:");
return rs;
}
public static void closeConnection(){
System.out.println("关闭连接中...");
try {
if (rs != null) {
rs.close();
System.out.println("已关闭ResultSet");
}
if (ps != null) {
ps.close();
System.out.println("已关闭Statement");
}
if (conn != null) {
conn.close();
System.out.println("已关闭Connection");
}
} catch (Exception e) {
// TODO: handle exception
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
ConnectionDemo.getConnection();
String sql = "delete from type where id = 1";
ConnectionDemo.getStatement(sql);
String sql2 = "insert into type values(1,'教学设备')";
ConnectionDemo.getStatement(sql2);
String sql1 = "select * from type";
ConnectionDemo.getStatement(sql1);
ResultSet rs = ConnectionDemo.getResultSet();
System.out.println("编号 "+"类型");
try {
while(rs.next()){
System.out.print(" "+rs.getInt(1)+"");
System.out.println(rs.getString(2));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
ConnectionDemo.closeConnection();
}
}
JAVA连接数据库连接代码怎么写？1 将数据库java该数据库代码的JDBC驱动加载到classpath中java该数据库代码，在基于JAVAEE的WEB应用实际开发过程中，通常要把目标数据库产品的JDBC驱动复制到WEB-INF/lib下.

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