Java数据库连接池-proxool

连接池技术的思想：

　　　　连接复用（高效、安全），避免数据库频繁建立、关闭的开销

--------------------极客学院（参考lulei）

1.配置文件

<proxool>
    <!-- 连接池别名 -->
    <alias>localmysqldb</alias>
       <!-- 连接数据库的驱动URL -->
       <driver-url><![CDATA[jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8]]></driver-url>
    <!-- 连接数据库的驱动类  -->
    <driver-class>com.mysql.jdbc.Driver</driver-class>
    <driver-properties>
      <property name="user" value="root"/>
      <property name="password" value="ROOT"/>
    </driver-properties>
    <!-- 处于睡眠的最大时间 -->
     <house-keeping-sleep-time>900000</house-keeping-sleep-time>
     <!-- 连接的最大活动时间 -->
     <maximum-active-time>500000</maximum-active-time>
     <!-- 最大的连接数量 -->
     <maximum-connection-count>10</maximum-connection-count>
     <!-- 最小的连接数量 -->
     <minimum-connection-count>4</minimum-connection-count>
     <!-- 检测连接是否处于空闲状态，执行这条语句来测试 -->
    <house-keeping-test-sql>select 1</house-keeping-test-sql>
    <prop key="hibernate.connection.release_mode">after_transaction</prop>
</proxool>
</proxool-config>

2。工具类

public class ClassUtil {

    /**
     * @param c
     * @return
     * @Author:
     * @Description: 返回class文件所在的目录
     */
    public static String getClassPath(Class<?> c) {
        return c.getResource("").getPath().replaceAll("%20", " ");
    }

    /**
     * @param c
     * @return
     * @Author:
     * @Description: 返回class文件所在项目的根目录
     */
    public static String getClassRootPath(Class<?> c) {
        return c.getResource("/").getPath().replaceAll("%20", " ");
    }

    /**
     * @param c
     * @param hasName 是否包括class名
     * @return
     * @Author:
     * @Description: 返回class文件所在的目录
     */
    public static String getClassPath(Class<?> c, boolean hasName) {
        String name = c.getSimpleName() + ".class";
        String path = c.getResource(name).getPath().replaceAll("%20", " ");
        if (hasName) {
            return path;
        } else {
            return path.substring(0, path.length() - name.length());
        }
    }

}

3.数据库连接池配置加载类

public class DBPool {
    private String poolPath;//数据库连接池的配置文件路径

    private DBPool() {
    }

    /**
     * @return
     * @Author:
     * @Description: 返回DBPool对象
     */
    public static DBPool getDBPool() {
        return DBPoolDao.dbPool;
    }

    /**
     *@Description: 静态内部类实现单例模式
     *@Author:
     *@Version:1.1.0
     */
    private static class DBPoolDao{
        private static DBPool dbPool = new DBPool();
    }

    public String getPoolPath() {
        if (poolPath == null) {
            //如果poolPath为空，赋值为默认值
            poolPath = ClassUtil.getClassRootPath(DBPool.class) + "proxool.xml";
        }
        return poolPath;
    }

    /**
     * @param poolPath
     * @Author:
     * @Description: 设置数据库连接池的配置文件路径
     */
    public void setPoolPath(String poolPath) {
        this.poolPath = poolPath;
    }

}

4.数据库连接池管理类

public class DBManager {

    private DBManager(){
        try {
            //数据库连接池配置文件
            JAXPConfigurator.configure(DBPool.getDBPool().getPoolPath(), false);
            //数据库加载驱动类
            Class.forName("org.logicalcobwebs.proxool.ProxoolDriver");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**
     * @param poolName
     * @return
     * @throws SQLException
     * @Author:
     * @Description: 获取数据库连接
     */
    public Connection getConnection(String poolName) throws SQLException {
        return DriverManager.getConnection(poolName);
    }

    /**
     *@Description: 内部静态类实现单例模式
     *@Author:
     *@Version:1.1.0
     */
    private static class DBManagerDao {
        private static DBManager dbManager = new DBManager();
    }

    /**
     * @return
     * @Author:
     * @Description: 返回数据库连接池管理类
     */
    public static DBManager getDBManager() {
        return DBManagerDao.dbManager;
    }

}

5. sql语句参数转化

public class DBOperation {
    private String poolName;//数据库连接池别名
    private Connection con = null;//数据库连接

    public DBOperation(String poolName) {
        this.poolName = poolName;
    }

    /**
     * @Author:
     * @Description:关闭数据库连接
     */
    public void close() {
        try {
            if (this.con != null) {
                this.con.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * @throws SQLException
     * @Author:lulei
     * @Description: 打开数据库连接
     */
    private void open() throws SQLException {
        //先关闭后打开，防止数据库连接溢出
        close();
        this.con = DBManager.getDBManager().getConnection(this.poolName);
    }

    /**
     * @param sql
     * @param params
     * @return
     * @throws SQLException
     * @throws ClassNotFoundException
     * @Author:
     * @Description: sql语句参数转化
     */
    private PreparedStatement setPres(String sql, HashMap<Integer, Object> params) throws SQLException, ClassNotFoundException{
        if (null == params || params.size() < 1) {
            return null;
        }
        PreparedStatement pres = this.con.prepareStatement(sql);
        for (int i = 1; i <= params.size(); i++) {
            if (params.get(i) == null) {
                pres.setString(i, "");
            } else if (params.get(i).getClass() == Class.forName("java.lang.String")) {
                pres.setString(i, params.get(i).toString());
            } else if (params.get(i).getClass() == Class.forName("java.lang.Integer")) {
                pres.setInt(i, (Integer) params.get(i));
            } else if (params.get(i).getClass() == Class.forName("java.lang.Long")) {
                pres.setLong(i, (Long) params.get(i));
            } else if (params.get(i).getClass() == Class.forName("java.lang.Double")) {
                pres.setDouble(i, (Double) params.get(i));
            } else if (params.get(i).getClass() == Class.forName("java.lang.Flaot")) {
                pres.setFloat(i, (Float) params.get(i));
            } else if (params.get(i).getClass() == Class.forName("java.lang.Boolean")) {
                pres.setBoolean(i, (Boolean) params.get(i));
            } else if (params.get(i).getClass() == Class.forName("java.sql.Date")) {
                pres.setDate(i, java.sql.Date.valueOf(params.get(i).toString()));
            } else {
                return null;
            }
        }
        return pres;
    }

    /**
     * @param sql
     * @return
     * @throws SQLException
     * @Author:
     * @Description: 执行SQL语句，返回影响行数
     */
    public int executeUpdate(String sql) throws SQLException {
        this.open();
        Statement state = this.con.createStatement();
        return state.executeUpdate(sql);
    }

    /**
     * @param sql
     * @param params
     * @return
     * @throws SQLException
     * @throws ClassNotFoundException
     * @Author:
     * @Description: 执行sql语句，返回影响行数
     */
    public int executeUpdate(String sql, HashMap<Integer, Object> params) throws SQLException, ClassNotFoundException {
        this.open();
        PreparedStatement pres = setPres(sql, params);
        if (null == pres) {
            return 0;
        }
        return pres.executeUpdate();
    }

    /**
     * @param sql
     * @return
     * @throws SQLException
     * @Author:
     * @Description: 执行sql语句，返回结果集
     */
    public ResultSet executeQuery(String sql) throws SQLException {
        this.open();
        Statement state = this.con.createStatement();
        return state.executeQuery(sql);
    }

    /**
     * @param sql
     * @param params
     * @return
     * @throws SQLException
     * @throws ClassNotFoundException
     * @Author:
     * @Description:执行sql语句，返回结果集
     */
    public ResultSet executeQuery(String sql, HashMap<Integer, Object> params) throws SQLException, ClassNotFoundException {
        this.open();
        PreparedStatement pres = setPres(sql, params);
        if (null == pres) {
            return null;
        }
        return pres.executeQuery();
    }

}

6.数据基本操作

public class DBServer {
    private DBOperation dbOperation;

    public DBServer(String poolName) {
        dbOperation = new DBOperation(poolName);
    }

    /**
     * @Author:
     * @Description: 关闭数据库连接
     */
    public void close() {
        dbOperation.close();
    }

    /**
     * @param sql
     * @return
     * @throws SQLException
     * @Author:
     * @Description: 数据库新增操作
     */
    public int insert(String sql) throws SQLException {
        return dbOperation.executeUpdate(sql);
    }

    /**
     * @param tableName
     * @param columns
     * @param params
     * @return
     * @throws SQLException
     * @throws ClassNotFoundException
     * @Author:
     * @Description: 数据库新增操作
     */
    public int insert(String tableName, String columns, HashMap<Integer, Object> params) throws SQLException, ClassNotFoundException {
        String sql = insertSql(tableName, columns);
        return dbOperation.executeUpdate(sql, params);
    }

    /**
     * @param sql
     * @return
     * @throws SQLException
     * @Author:
     * @Description: 数据库删除操作
     */
    public int delete(String sql) throws SQLException {
        return dbOperation.executeUpdate(sql);
    }

    /**
     * @param tableName
     * @param condition
     * @return
     * @throws SQLException
     * @Author:lulei
     * @Description: 数据库删除操作
     */
    public int delete(String tableName, String condition) throws SQLException {
        if (null == tableName) {
            return 0;
        }
        String sql = "delete from " + tableName + " " + condition;
        return dbOperation.executeUpdate(sql);
    }

    /**
     * @param sql
     * @return
     * @throws SQLException
     * @Author:
     * @Description: 数据库更新操作
     */
    public int update(String sql) throws SQLException {
        return dbOperation.executeUpdate(sql);
    }

    /**
     * @param tableName
     * @param columns
     * @param condition
     * @param params
     * @return
     * @throws SQLException
     * @throws ClassNotFoundException
     * @Author:
     * @Description: 数据库更新操作
     */
    public int update(String tableName, String columns, String condition, HashMap<Integer, Object> params) throws SQLException, ClassNotFoundException {
        String sql = updateSql(tableName, columns, condition);
        return dbOperation.executeUpdate(sql, params);
    }

    /**
     * @param sql
     * @return
     * @throws SQLException
     * @Author:
     * @Description: 数据库查询操作
     */
    public ResultSet select(String sql) throws SQLException {
        return dbOperation.executeQuery(sql);
    }

    /**
     * @param tableName
     * @param columns
     * @param condition
     * @return
     * @throws SQLException
     * @Author:lulei
     * @Description: 数据库查询操作
     */
    public ResultSet select(String tableName, String columns, String condition) throws SQLException {
        String sql = "select " + columns + " from " + tableName + " " + condition;
        return dbOperation.executeQuery(sql);
    }

    /**
     * @param tableName
     * @param columns
     * @param condition
     * @return
     * @Author:
     * @Description: 组装 update sql eg: update tableName set column1=?,column2=? condition
     */
    private String updateSql(String tableName, String columns, String condition) {
        if (tableName == null || columns == null) {
            return "";
        }
        String[] column = columns.split(",");
        StringBuilder sb = new StringBuilder();
        sb.append("update ");
        sb.append(tableName);
        sb.append(" set ");
        sb.append(column[0]);
        sb.append("=?");
        for (int i = 1; i < column.length; i++) {
            sb.append(", ");
            sb.append(column[i]);
            sb.append("=?");
        }
        sb.append(" ");
        sb.append(condition);
        return sb.toString();
    }

    /**
     * @param tableName
     * @param columns
     * @return
     * @Author:
     * @Description: 组装 insert sql eg: insert into tableName (column1, column2) values (?,?)
     */
    private String insertSql(String tableName, String columns) {
        if (tableName == null || columns == null) {
            return "";
        }
        int n = columns.split(",").length;
        StringBuilder sb = new StringBuilder("");
        sb.append("insert into ");
        sb.append(tableName);
        sb.append(" (");
        sb.append(columns);
        sb.append(") values (?");
        for (int i = 1; i < n; i++) {
            sb.append(",?");
        }
        sb.append(")");
        return sb.toString();
    }

}