轉自:http://java-lyvee.iteye.com/blog/651168 作者:java_lyvee
package com.test.db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* @(#)DataBase.java 010/04/22
* @author Dudu
* EST.All rights reserved
*/
public class DataBase {
/**定義一個Connection 用來連接數據庫*/
private Connection conn=null;
/**連接數據庫的URL*/
private final String url="jdbc:mysql://localhost/lyvee";
/**指定數據的用戶名和密碼*/
private final String username="root";
private final String password="123";
/**定義一個int記錄更新的記錄數量*/
int count=0;
/**定義一個結果集 用於放回查詢結果*/
private ResultSet resultSet=null;
private PreparedStatement pstmt=null;
public DataBase(){
conn = connectionDB();
}
/**
* 建立數據的連接
* @exception SQLException, ClassNotFoundException
*/
@SuppressWarnings("finally")
public Connection connectionDB(){
try{
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection(url,username,password);
System.out.println("連接數據庫成功");
}catch(Exception e){
e.printStackTrace();
System.out.println("建立數據庫發生錯誤!");
}finally{
return conn;
}
}
/**
* 查詢方法
* @param sql查詢sql語句
* @return resultSet
*/
@SuppressWarnings("finally")
public ResultSet query(String sql){
try {
pstmt = conn.prepareStatement(sql);
/**查詢*/
resultSet = pstmt.executeQuery();
} catch (SQLException e) {
e.printStackTrace();
}finally{
return resultSet;
}
}
/**
* 更新數據
* @param sql 更新sql語句
* @return
*/
public int update(String sql){
try {
pstmt = conn.prepareStatement(sql);
count=pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
System.out.println("執行更新出錯了");
}
return count;
}
/**關閉連接*/
public boolean coles(){
boolean isColes = false;
if(resultSet!=null){
try {
resultSet.close();
resultSet=null;
isColes=true;
} catch (SQLException e) {
isColes=false;
e.printStackTrace();
System.out.println("關閉結果集發生錯誤");
}
}
if(pstmt!=null){
try {
pstmt.close();
pstmt=null;
isColes=true;
} catch (SQLException e) {
isColes=false;
e.printStackTrace();
System.out.println("關閉pstmt發生異常");
}
}
if(conn!=null){
try{
conn.close();
conn=null;
isColes=true;
}catch (Exception e) {
isColes=false;
e.printStackTrace();
System.out.println("關閉conn發生異常");
}
}
return isColes;
}
/**
* 測試查詢的方法
* @throws SQLException
*/
public void testQuery() throws SQLException{
resultSet =query("select * from lyvee");
if(resultSet.next()){
System.out.println(resultSet.getString(1));
System.out.println(resultSet.getString(3));
System.out.println(resultSet.getString(2));
}
}
public void testUpdate(){
count = update("insert into lyvee(lname,lpwd,lsex)values('tanliang','aaa111','sex')");
if(count>0){
System.out.println("更新成功");
}
}
/**
*
* @param args
* @throws SQLException
* @throws ClassNotFoundException
*/
public static void main(String[] args) throws SQLException, ClassNotFoundException {
DataBase db = new DataBase();
/**調用查詢方法*/
//db.testQuery();
/**調用更新方法*/
db.testUpdate();
/**調用關閉連接方法*/
db.coles();
}
}