Java JDBC
Java JDBC 连接Oracle和MySql数据库
本文是通过Java JDBC连接Oracle和MySql数据库，其中用到了使用properties配置文件，所以在ConnectionFactory中java.util.Properties解析db-conn-config.properties配置文件。
1.首先看看db-conn-param.properties的写法：
#######################Oracle########################### oracle.driver: oracle.jdbc.driver.OracleDriver oracle.url: jdbc:oracle:thin:@localhost:1521:xcz oracle.username: scott oracle.password: tiger #######################Oracle########################### ######################MYSQL############################# mysql.driver = com.mysql.jdbc.Driver mysql.url = jdbc:mysql://localhost:3306/mysql mysql.username = root mysql.password = xcz ######################MYSQL#############################
注意：
* "oracle.jdbc.driver.OracleDriver" 等字符串前后面不可以有空格，否则会出现找不到驱动或用户名、密码错误等异常。
* properties 中字符串写入形式如同键值对，所以可以同上使用“=”或“：”把key与value隔开。
* properties 中value字符串不能使用引号包裹。
2.创建ConnectionFactory:
package com.orcl.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
import java.util.UUID;
public class ConnectionFactory {
/**
* 驱动
*/
private String driver;
/**
* 连接字符串
*/
private String url;
/**
* 数据库登录用户名称
*/
private String username;
/**
* 数据库登录密码
*/
private String password;
private String db;
/**
* 常量代表"ORACLE"
*/
public final static String ORACLE_DB = "oracle";
/**
* 常量代表"MYSQL"
*/
public final static String MYSQL_DB = "mysql";
/**
* 单例模式 获取一个数据库连接工厂
*/
private static ConnectionFactory connFactory = null;
public static synchronized ConnectionFactory getConnFactoryInstance(String db){
if(connFactory == null){
connFactory = new ConnectionFactory(db);
}
return connFactory;
}
private ConnectionFactory(String db){
try {
initOrclParams(db);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 通过配置文件获取数据库连接参数
* @param db 数据库名称
* @throws IOException
*/
private void initOrclParams(String db) throws IOException{
Properties properties = new Properties();
InputStream in = new FileInputStream(new File("db-conn-config.properties"));
properties.load(in);
if(db.equals(ORACLE_DB))
{
getParams(properties,db);
}
else if(db.equals(MYSQL_DB))
{
getParams(properties,db);
}
}
/**
* 根据数据库名获取相应的参数
* @param p Properties
* @param db
*/
private void getParams(Properties p,String db){
//注意：如果不用trim(),这样properties文件中的字符串后面不能有空格，否则会出错
driver = p.getProperty(db + ".driver").trim();
url = p.getProperty(db + ".url").trim();
username = p.getProperty(db + ".username").trim();
password = p.getProperty(db + ".password").trim();
}
/**
* 获取连接对象
* @param db 连接的数据库名 取值于ConnectionFactory中的常量：ORCL_DB/MYSQL_DB
* @return
*/
public Connection getConn()
{
Connection conn = null;
try
{
Class.forName(driver);
conn = DriverManager.getConnection(url, username, password);
// 设置不自动提交
conn.setAutoCommit(false);
}
catch (ClassNotFoundException e)
{
e.printStackTrace();
}
catch (SQLException e)
{
e.printStackTrace();
}
return conn;
}
/**
* 关闭操作
* @param conn
* @param pst
* @param rs
*/
public static void close(Connection conn, PreparedStatement pst, ResultSet rs) {
try {
if (rs != null) {
rs.close();
}
if (pst != null) {
pst.close();
}
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* 获取UUID
* @return
*/
public String getUUID() {
return UUID.randomUUID().toString();
}
public void setPassword(String password) {
this.password = password;
}
public String getDriver() {
return driver;
}
public void setDriver(String driver) {
this.driver = driver;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public String getDb() {
return db;
}
public void setDb(String db) {
this.db = db;
}
}
3.测试：
@Test
public void test() {
ConnectionFactory factory = ConnectionFactory.getConnFactoryInstance(ConnectionFactory.ORACLE_DB);
Connection conn = factory.getConn();
try {
PreparedStatement pst = conn.prepareStatement("select * from emp");
java.sql.ResultSet rs = pst.executeQuery();
while (rs.next()) {
System.out.println(rs.getString(2));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
附录：
关于properties，生产xml,并从其中解析出来的应用
Properties prop = new Properties();
prop.setProperty("ONE", "1");
prop.setProperty("TWO", "2");
prop.setProperty("THREE", "3");
prop.setProperty("FOUR", "4");
File f = new File("temp.xml");
if(!f.exists()){
f.createNewFile();
}
OutputStream stream = new FileOutputStream(f);
prop.storeToXML(stream, null);
stream.close();
解析：
Properties p = new Properties();
p.loadFromXML(new FileInputStream(f));
System.out.println(p.get("ONE"));
System.out.println(p.getProperty("TOW"));
p.list(System.out);
还有许多其他捷径方法，待应用后总结......