建立一个JDBC

1:找驱动 在oracle安装文件目录 oracle安装目录 product11.2.0dbhome_1jdbclib 只需要在里面找1个你喜欢的包 我们常用的是ojdbc6.jar

2：把包放入工程里面的lib文件夹中 如果没有lib文件夹就建一个（这里文件夹的名字一定要是lib） 右键工程名 new -folder 点flinsh

3：右键工程名 buildpath-configure buildpath  点击 add JARS… 选择lib 文件夹里面的 ojdbc6.jar 点击ok     点击OK

注意：建包的时候不要oracle.jdbc 因为oracle.jdbc这个包名在我们的jdbc包里面已经有了，你这么起名字 java就不知道应该找那个包了

初级程序如下：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class jdbcText {
public static void main(String args[]){
Connection c=null;
PreparedStatement ps=null;
ResultSet rs=null;
try {
//1：加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
//2:获得链接
c=DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:orcl","scott","ztoracle");
//3用PreparedStatement执行sql语句
ps=c.prepareStatement("select * from emp");
//4：对执行结果的操作
rs=ps.executeQuery();
while(rs.next()){
System.out.println(rs.getString(2));
}
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//5：关闭各种资源
catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
rs=null;
throw new RuntimeException();
}
}
if(ps!=null){
try {
ps.close();
} catch (SQLException e) {
ps=null;
throw new RuntimeException();
}
}
if(c!=null){
try {
c.close();
} catch (SQLException e) {
c=null;
throw new RuntimeException();
}
}
}
}
}

改良程序

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

//这里采用了单例设计模式 私有的构造方法,静态的对象,公开的静态的getInstance方法
public class HelpJdbc {
private Connection c=null;
private PreparedStatement ps=null;
private ResultSet rs;
public static HelpJdbc hj=null;
public static HelpJdbc getInstance(){
if(hj==null){
hj=new HelpJdbc();
}
return hj;
}
private HelpJdbc(){
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
throw new RuntimeException();
}
}
public int exeDml(String sql){
try {
c=DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:orcl","scott","ztoracle");
ps=c.prepareStatement(sql);
return ps.executeUpdate(sql);
} catch (SQLException e) {
throw new RuntimeException();
}
}
public ResultSet querry(String sql){
ResultSet rs=null;
try {
c=DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:orcl","scott","ztoracle");
ps=c.prepareStatement(sql);
rs=ps.executeQuery();
} catch (SQLException e) {
throw new RuntimeException();
}
return rs;
}
public void closeRes(){
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
rs=null;
throw new RuntimeException();
}
}
if(ps!=null){
try {
ps.close();
} catch (SQLException e) {
ps=null;
throw new RuntimeException();
}
}
if(c!=null){
try {
c.close();
} catch (SQLException e) {
c=null;
throw new RuntimeException();
}
}
}
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class jdbcText {
public static void main(String args[]){
HelpJdbc hj=HelpJdbc.getInstance();
ResultSet rs=hj.querry("select ename from emp");
try {
while(rs.next()){

System.out.println(rs.getString("ename"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// hj.exeDml("update emp set ename='zhangtao' where ename='SMITH'");
// hj.exeDml("insert into emp(empno,ename) values(777,'huge')");
hj.closeRes();
}
}