/////////jdbc连接操作
private static String url;
/**
* 用户名
*/
private static String userName;
/**
* 密码
*/
private static String password;
private static String driver;
// 连接池
private static int max = 20;
private static int min = 2;
private static int count = 0;
private static List<Connection> freeConn = new ArrayList<Connection>();
// private static List<Connection> useConn = new ArrayList<Connection>();
/**
* 装载驱动
*/
static {
DbConfig config = new DbConfig();
url = config.getUrl();
userName = config.getUserName();
password = config.getPassword();
driver = config.getDriver();
try {
Class.forName(driver);
} catch (ClassNotFoundException e) {
throw new ExceptionInInitializerError(e);
}
initCon();
}
public static void initCon() {
try {
// 初始化
Connection conn;
if (count > max) {// 如果大于 最大，就只new一个;
conn = DriverManager.getConnection(url, userName, password);
freeConn.add(conn);
} else {
for (int i = 0; i < min; i++) {
conn = DriverManager.getConnection(url, userName, password);
freeConn.add(conn);
count++;
}
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 建立数据库连接
*
* @return
* @throws SQLException
*/
public static synchronized Connection getConnection() throws SQLException {
if (null == freeConn || freeConn.size() == 0) {
initCon();
}
Connection conn = freeConn.get(0);
freeConn.remove(0);
if (conn.isClosed()) {// 已关闭，去找未关闭的连接
while (true) {
conn = freeConn.get(0);
if (!conn.isClosed()) {// 未关闭
freeConn.remove(0);//如果移除完了，就重新init连接
break;
}
freeConn.remove(0);//如果移除完了，就重新init连接
if (null == freeConn || 0 == freeConn.size()) {
initCon();
}
}
}
return conn;
// conn = DriverManager.getConnection(url, userName, password);
// return conn;
}
/**
* 释放连接
*
* @param conn
*/
private static void freeConnection(Connection conn) {
freeConn.add(conn);
// try {
// conn.close();
// } catch (SQLException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
}
/**
* 释放statement
*
* @param statement
*/
private static void freeStatement(Statement statement) {
try {
statement.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 释放resultset
*
* @param rs
*/
private static void freeResultSet(ResultSet rs) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 释放资源
*
* @param conn
* @param statement
* @param rs
*/
public static void free(Connection conn, Statement statement, ResultSet rs) {
if (rs != null) {
freeResultSet(rs);
}
if (statement != null) {
freeStatement(statement);
}
if (conn != null) {
freeConnection(conn);
}
}
////////////////////////////////查询操作
/**
* 根据sql获得 obj对象集合的数据
* @param sql
* @param cla
* @param paramters
* @return
* @throws Exception
*/
@SuppressWarnings("rawtypes")
public static List<Object> queryObjs(String sql,Class cla, Object... paramters)
throws Exception {
ResultSet rs = null;
try {
getPreparedStatement(sql);
for (int i = 0; i < paramters.length; i++) {
preparedStatement.setObject(i + 1, paramters[i]);
}
rs = preparedStatement.executeQuery();
// ResultToListObj(ResultSet rs,Class cla)
return ResultToListObj(rs,cla);
} catch (SQLException e) {
throw new SQLException(e);
} finally {
free(rs);
}
}
/**
* 获取PreparedStatement
*
* @param sql
* @throws SQLException
*/
private static void getPreparedStatement(String sql) throws SQLException {
conn = JdbcUnits.getConnection();
preparedStatement = conn.prepareStatement(sql);
}
/**
* 用于增删改
*
* @param sql
* sql语句
* @return 影响行数
* @throws SQLException
*/
public static int update(String sql) throws SQLException {
try {
getPreparedStatement(sql);
return preparedStatement.executeUpdate();
} catch (SQLException e) {
throw new SQLException(e);
} finally {
free();
}
}
/**
* 用于增删改（带参数）
*
* @param sql
* sql语句
* @param paramters
* sql语句
* @return 影响行数
* @throws SQLException
*/
public static int update(String sql, Object... paramters)
throws SQLException {
try {
getPreparedStatement(sql);
for (int i = 0; i < paramters.length; i++) {
preparedStatement.setObject(i + 1, paramters[i]);
}
return preparedStatement.executeUpdate();
} catch (SQLException e) {
throw new SQLException(e);
} finally {
free();
}
}
/**
* 返回obj对象的数据
* @param rs
* @param cla
* @return
* @throws Exception
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
private static List<Object> ResultToListObj(ResultSet rs,Class cla) throws Exception {
List list = new ArrayList();
// Class cla = Mystudy.class;
//获取全部公共域的方法
Field[] field=cla.getDeclaredFields();//获得定义的属性
// for(Field f:field){
// System.out.println("获取全部公共域的方法:"+f.toString());
// }
while (rs.next()) {
ResultSetMetaData md = rs.getMetaData();
// Map<String,String> map = new HashMap<String,String>();
Object obj = cla.newInstance();//获得类实例
for (int i = 1; i <= md.getColumnCount(); i++) {
// System.out.println(md.getColumnType(i)+":"+md.getColumnLabel(i)+">>>>>"+rs.getObject(i));
// int tmp = md.getColumnType(i);
for(Field f:field){
// System.out.println(f.getName()+">>"+f.getType()); );
if(f.getName().equalsIgnoreCase(md.getColumnLabel(i))){//属性与表列名相同
if("int".equalsIgnoreCase(f.getType()+"")){
PropertyDescriptor pd = new PropertyDescriptor(f.getName(), cla);
Method wM = pd.getWriteMethod();//获得写方法
wM.invoke(obj, stringToInt(rs.getObject(i)+""));
}else if("long".equalsIgnoreCase(f.getType()+"")){
PropertyDescriptor pd = new PropertyDescriptor(f.getName(), cla);
Method wM = pd.getWriteMethod();//获得写方法
wM.invoke(obj, stringToLong(rs.getObject(i)+""));
}else{
PropertyDescriptor pd = new PropertyDescriptor(f.getName(), cla);
Method wM = pd.getWriteMethod();//获得写方法
wM.invoke(obj,rs.getObject(i)+"");
}
break;
}
}
// map.put(md.getColumnLabel(i), rs.getObject(i)+"");
}
list.add(obj);
}
return list;
}
/////////////////////////////////用户查询示例
public Video getVideoObjByid(int video_id) {
StringBuffer sql = new StringBuffer();
sql.append(" select * from video ");
sql.append(" where id = ? ");
sql.append(" limit 1 ");
try {
List<Object> objList = JdbcHelper.queryObjs(sql.toString(), Video.class, video_id);
Video o = null;
if (null != objList && objList.size() > 0) {
o = (Video) objList.get(0);
}
return o;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}