简单工具类：
public class JDBCSimpleUtils {
/**
* 私有构造方法
*/
private JDBCSimpleUtils() {
}
/**
* 驱动
*/
public static String driver = null;
/**
* 连接字符串
*/
public static String url = null;
/**
* 用户名
*/
public static String user = null;
/**
* 密码
*/
public static String password = null;
/**
* 读取配置文件, 并将读取到的值赋值给变量.
*/
public static void readConfig() {
try {
//读取properties配置文件给变量赋值
Properties pp = new Properties();
pp.load(new FileReader("day04_classTest\\src\\config.properties"));
url = pp.getProperty("url");
user = pp.getProperty("username");
driver = pp.getProperty("driver");
password = pp.getProperty("password");
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 静态代码块
* 变量赋值
* 并注册驱动
*/
static {
try {
//变量赋值
readConfig();
//注册驱动
Class.forName(driver);
} catch (Exception e) {
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
e.printStackTrace();
}
}
/**
* 获取Connection
*
* @return 数据库连接
*/
public static Connection getConnection() {
try {
return DriverManager.getConnection(url, user, password);
} catch (SQLException ex) {
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
ex.printStackTrace();
return null;
}
}
public static Statement getStatement(Connection conn) {
if (conn == null) {
return null;
}
try {
return conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);
// 设置数据集可以滚动,可以更新
} catch (SQLException ex) {
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
release(conn);
}
return null;
}
/**
* 获取一个带参数的 PreparedStatement
* 该 PreparedStatement 已经设置数据集 可以滚动,可以更新
*
* @param conn 数据库连接
* @param cmdText 需要 ? 参数的 SQL 语句
* @param cmdParams SQL 语句的参数表
* @return 如果获取失败将返回 null,调用时记得检查返回值
*/
public static PreparedStatement getPreparedStatement(Connection conn, String cmdText, Object... cmdParams) {
if (conn == null) {
return null;
}
PreparedStatement pstmt = null;
try {
pstmt = conn.prepareStatement(cmdText, ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
int i = 1;
for (Object item : cmdParams) {
pstmt.setObject(i, item);
i++;
}
} catch (SQLException e) {
e.printStackTrace();
release(conn, pstmt);
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
}
return pstmt;
}
/**
* 释放资源
*
* @param conn Connection
* @param stat Statement
* @param rs ResultSet
*/
public static void release(Connection conn, Statement stat, ResultSet rs) {
try {
if (rs != null) {
rs.close();
rs = null;
}
} catch (SQLException e) {
e.printStackTrace();
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
} finally {
try {
if (stat != null) {
stat.close();
stat = null;
}
} catch (SQLException e) {
e.printStackTrace();
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
} finally {
try {
if (conn != null) {
conn.close();
conn = null;
}
} catch (SQLException e) {
e.printStackTrace();
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
}
}
}
}
/**
* 释放资源
*
* @param conn Connection
* @param stat Statement
*/
public static void release(Connection conn, Statement stat) {
try {
if (stat != null) {
stat.close();
stat = null;
}
} catch (SQLException e) {
e.printStackTrace();
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
} finally {
try {
if (conn != null) {
conn.close();
conn = null;
}
} catch (SQLException e) {
e.printStackTrace();
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
}
}
}
/**
* 释放资源
*
* @param conn Connection
*/
public static void release(Connection conn) {
try {
if (conn != null) {
conn.close();
conn = null;
}
} catch (SQLException e) {
e.printStackTrace();
//写入日志
//Logger.WriteLog(JDBCUtils.class.getName(),"");
}
}
}简单工具类的应用：
/**
* 增删改的方法
*
* @param sql
* @param obj
*/
private static void executeNoQuery(String sql, Object... obj) {
//获取Connection
Connection conn = JDBCSimpleUtils.getConnection();
//获取PreparedStatement
PreparedStatement ps = JDBCSimpleUtils.getPreparedStatement(conn, sql, obj);
try {
int i = ps.executeUpdate();
if (i > 0) {
System.out.println("ok");
} else {
System.out.println("error");
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JDBCSimpleUtils.release(conn, ps);
}
} /**
* 查询返回ResultSet
*
* @param sql
*/
private static void getResultSet(String sql) {
//获取Connection
Connection conn = JDBCSimpleUtils.getConnection();
//获取Statement
Statement stat = JDBCSimpleUtils.getStatement(conn);
ResultSet rs = null;
try {
rs = stat.executeQuery(sql);
while (rs.next()) {
int id = rs.getInt("uid");
String name = rs.getString("uname");
String psw = rs.getString("psw");
System.out.println(id + "--" + name + "--" + psw);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JDBCSimpleUtils.release(conn, stat, rs);
}
}