public class DB { private Connection con = null; private String classname = "com.microsoft.sqlserver.jdbc.SQLServerDriver"; private String url = "jdbc:sqlserver://localhost:1433;DatabaseName=ZSB";
public static void main(String [] args){ DBOperate db = new DBOperate(); ResultSet rs=db.openQuery("select *from download"); try{ int id=1; while(rs.next()){ int t=rs.getInt("id"); if(t==id){ id++; }
Connection con = DriverManager.getConnection(url, name, password); 取得数据库连接
Statement stmt = con.createStatement(); 创建一个语句,用于执行sql语句,如
Result rs = stmt.executeQuery("select * from tableName");然后返回的结果集就是查询到的结果。
import java.sql.*;
public class DB {
private Connection con = null;
private String classname = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
private String url = "jdbc:sqlserver://localhost:1433;DatabaseName=ZSB";
public DB(){
}
public Connection getCon(){
try{
Class.forName(classname);
}catch(ClassNotFoundException e){
e.printStackTrace();
}
try{
con=DriverManager.getConnection(url, "sa", "");
System.out.println("数据库连接成功!");
}catch(Exception e){
e.printStackTrace(System.err);
con=null;
}
return con;
}
public void closed(){
try{
if(con!=null)con.close();
}catch(SQLException e){
e.printStackTrace();
}
}
public static void main(String [] args){
}
}
package hy;
import java.sql.*;
public class DBOperate extends DB{
private Connection conn=null;
private Statement stm = null;
private ResultSet rs = null;
public DBOperate(){
}
public int exeQuery(String str){
int success = 0;
try{
if(conn==null){
conn = super.getCon();
}
stm = conn.createStatement();
success = stm.executeUpdate(str);
}catch(SQLException e){
e.printStackTrace();
success = 0;
}
return success;
}
public ResultSet openQuery(String str){
try{
if(conn==null){
conn = super.getCon();
}
Statement stm = conn.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY );
rs = stm.executeQuery(str);
}catch(SQLException e){
e.printStackTrace();
rs = null;
}
return rs;
}
public static void main(String [] args){
DBOperate db = new DBOperate();
ResultSet rs=db.openQuery("select *from download");
try{
int id=1;
while(rs.next()){
int t=rs.getInt("id");
if(t==id){
id++;
}
}
System.out.println(id);
}catch(SQLException e){
e.printStackTrace();
}
}
}
Connection con = DriverManager.getConnection(url, name, password); 取得数据库连接
Statement stmt = con.createStatement(); 创建一个语句,用于执行sql语句,如
Result rs = stmt.executeQuery("select * from tableName"); 也不说清楚连什么数据库,上面算是个大纲吧。
我比较喜欢用MySQL数据库,我帮你介绍一下Java连接MySQL吧;
首先下载相应版本的MySQL的jdbc的驱动,在MySQL的官方网站上就有,我用得是mysql-connector-java-5.1.8.zip。其中有一个jar包。我们用的就是它,其余的都是些源码什么的。
用工具eclipse,首先建立一个Java工程,在引入刚才的MySQL的驱动jar包。Class.forName("com.mysql.jdbc.driver");:加载数据库驱动
Connection con = DriverManager.getConnection(jdbc:mysql: database@localhost, name, password); 取得数据库连接
Statement stmt = con.createStatement(); 创建一个语句,用于执行sql语句,如
Result rs = stmt.executeQuery("select * from tableName"); 前提是在MySQL数据库中有相应的数据库;