java一些常用代码的分享(转载)

java访问xml文
XML code
<?xml version="1.0" encoding="gbk"?>
<Accounts>
<Account type="by0003">
<code>100001</code>
<pass>123</pass>
<name>李四</name>
<money>1000000.00</money>
</Account>
<Account type="hz0001">
<code>100002</code>
<pass>123</pass>
<name>张三</name>
<money>1000.00</money>
</Account>
</Accounts>
java jdbc数据库连接
Java code

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;


public class JDBConnection {
public Connection conn = null; // 声明Connection对象的实例
public Statement stmt = null; // 声明Statement对象的实例
public ResultSet rs = null; // 声明ResultSet对象的实例

private static String dbClassName = "com.microsoft.jdbc.sqlserver.SQLServerDriver";//定义保存数据库驱动的变量
private static String dbUrl = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=DB_ATM";
private static String dbUser = "sa";
private static String dbPwd = "sa";

public JDBConnection(String propertyFileName) {// 带属性文件名的构造方法
Properties prop = new Properties();// 属性集合对象
InputStream is = null;
try {
is
= JDBConnection.class.getClassLoader().getResourceAsStream(
propertyFileName);
// 属性文件输入流
// is = new FileInputStream("src/" + propertyFileName);
prop.load(is);// 将属性文件流装载到Properties对象中
is.close();// 关闭流
dbClassName = prop.getProperty("dbClassName");
dbUrl
= prop.getProperty("dbUrl");
dbUser
= prop.getProperty("dbUser");
dbPwd
= prop.getProperty("dbPwd");
}
catch (Exception e) {
System.out.println(
"属性文件 " + propertyFileName + " 打开失败!");
}
try {

Class.forName(dbClassName);
// 1.注册驱动
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}

public JDBConnection() {// 默认的不带参数的构造函数
try {

Class.forName(dbClassName);
// 1.注册驱动
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}

public static Connection getConnection() {
Connection conn
= null;
try {
// Class.forName(dbClassName);// 1.注册驱动
conn = DriverManager.getConnection(dbUrl, dbUser, dbPwd);//2.建立与数据库的链接
} catch (Exception ee) {
ee.printStackTrace();
}
if (conn == null) {
System.err
.println(
"警告: DbConnectionManager.getConnection() 获得数据库链接失败.\r\n\r\n链接类型:"
+ dbClassName
+ "\r\n链接位置:"
+ dbUrl
+ "\r\n用户/密码"
+ dbUser + "/" + dbPwd);
}
return conn;
}

/*
* 功能:执行查询语句
*/
public ResultSet executeQuery(String sql) {
try { // 捕捉异常
conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,//3.创建语句
ResultSet.CONCUR_READ_ONLY);
rs
= stmt.executeQuery(sql);//4.执行查询
} catch (SQLException ex) {
System.err.println(ex.getMessage());
// 输出异常信息
}
return rs; // 返回结果集对象 5.结果处理
}

/*
* 功能:执行更新操作
*/
public int executeUpdate(String sql) {
int result = 0; // 定义保存返回值的变量
try { // 捕捉异常
conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
result
= stmt.executeUpdate(sql); // 执行更新操作
} catch (SQLException ex) {
result
= 0; // 将保存返回值的变量赋值为0
}
return result; // 返回保存返回值的变量
}

/*
* 功能:关闭数据库的连接
*/
public void close() {//6.释放资源
try { // 捕捉异常
try {
if (rs != null) { // 当ResultSet对象的实例rs不为空时
rs.close(); // 关闭ResultSet对象
}
}
finally {
try {
if (stmt != null) { // 当Statement对象的实例stmt不为空时
stmt.close(); // 关闭Statement对象
}
}
finally {
if (conn != null) { // 当Connection对象的实例conn不为空时
conn.close(); // 关闭Connection对象
}
}
}
}
catch (Exception e) {
e.printStackTrace(System.err);
// 输出异常信息
}
}

}


属性文件
dbClassName
=com.microsoft.jdbc.sqlserver.SQLServerDriver
dbClassName2
=com.mysql.jdbc.Driver
dbPwd
=sa
dbPwd2
=root
dbUrl
=jdbc\:microsoft\:sqlserver\://localhost\:1433;DatabaseName\=DB_ATM
dbUrl2=jdbc\:mysql\://localhost\:3306/db_atm
dbUser=sa
dbUser2
=root

posted @ 2011-06-25 16:18  时游  阅读(177)  评论(0编辑  收藏  举报