JDBC封装

1.抽象类DaoSupport.java

package com.dao;

import java.util.List;

public abstract class DaoSupport
{
    /**
     *
     * {查询抽象方法}
     *
     * @param sql
     * @param rowMapper
     * @return
     * @author:LJ
     */
    @SuppressWarnings("unchecked")
    protected abstract List query(String sql, RowMapper rowMapper);

    /**
     *
     * {带参数查询抽象方法}
     *
     * @param sql
     * @param objs
     * @param rowMapper
     * @return
     * @author:LJ
     */
    @SuppressWarnings("unchecked")
    protected abstract List query(String sql, Object[] objs, RowMapper rowMapper);

    /**
     *
     * {更新抽象方法}
     *
     * @param sql
     * @param objs
     * @return
     * @author:LJ
     */
    protected abstract int update(final String sql, Object[] objs);

    /**
     *
     * {带参数更新抽象方法}
     *
     * @param sql
     * @return
     * @author:LJ
     */
    protected abstract int update(final String sql);

    /**
     *
     * {批处理抽象方法}
     *
     * @param sql
     * @return
     * @author:LJ
     */
    protected abstract int[] batchUpdate(String[] sql);
    /**
     *
     * {带参数批量处理方法}
     *
     * @param sql
     * @param pss
     * @return
     * @author:LJ
     */
    protected abstract int[] batchUpdate(final String sql, final BatchPreparedStatementSetter pss);
}

2.实现类BaseDao.java

package com.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class BaseDao
{
    private String driverClassName = "oracle.jdbc.driver.OracleDriver";

    private String username = "scott";

    private String password = "tiger";

    private String url = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";

    /**
     *
     * {查询}
     *
     * @param sql
     * @return
     * @author:LJ
     */
    @SuppressWarnings("unchecked")
    protected List query(String sql, RowMapper rowMapper)
    {
        Connection con = null;
        Statement stmt = null;
        ResultSet rs = null;
        List list = new ArrayList();
        try
        {
            Class.forName(driverClassName);
            con = DriverManager.getConnection(url, username, password);
            stmt = con.createStatement();
            rs = stmt.executeQuery(sql);
            while (rs.next())
            {
                list.add(rowMapper.map(rs));
            }
        }
        catch (ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
        finally
        {
            DBUtil.closeQuietly(rs);
            DBUtil.closeQuietly(stmt);
            DBUtil.closeQuietly(con);
        }
        return list;
    }

    /**
     *
     * {带参数查询}
     *
     * @param sql
     * @param objs
     * @return
     * @author:LJ
     */
    @SuppressWarnings("unchecked")
    protected List query(String sql, final Object[] objs, RowMapper rowMapper)
    {
        Connection con = null;
        PreparedStatement preparedStatement = null;
        ResultSet rs = null;
        List list = new ArrayList();
        try
        {
            Class.forName(driverClassName);
            con = DriverManager.getConnection(url, username, password);
            preparedStatement = con.prepareStatement(sql);
            if (objs != null && objs.length > 0)
            {
                for (int i = 0, n = objs.length; i < n; i++)
                {
                    preparedStatement.setObject(i + 1, objs[i]);
                }
            }
            rs = preparedStatement.executeQuery();
            while (rs.next())
            {
                list.add(rowMapper.map(rs));
            }
        }
        catch (SQLException e)
        {
            throw new RuntimeException(e);
        }
        catch (ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        finally
        {
            DBUtil.closeQuietly(rs);
            DBUtil.closeQuietly(preparedStatement);
            DBUtil.closeQuietly(con);
        }
        return list;
    }

    /**
     *
     * {修改}
     *
     * @param sql
     * @param objs
     * @return
     * @author:LJ
     */
    protected int update(final String sql, final Object[] objs)
    {
        Connection con = null;
        PreparedStatement preparedStatement = null;
        int retCode = 0;
        try
        {
            Class.forName(driverClassName);
            con = DriverManager.getConnection(url, username, password);
            preparedStatement = con.prepareStatement(sql);
            if (objs != null && objs.length > 0)
            {
                for (int i = 0, n = objs.length; i < n; i++)
                {
                    preparedStatement.setObject(i + 1, objs[i]);
                }
            }
            retCode = preparedStatement.executeUpdate();
        }
        catch (SQLException e)
        {
            throw new RuntimeException(e);
        }
        catch (ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        finally
        {
            DBUtil.closeQuietly(preparedStatement);
            DBUtil.closeQuietly(con);
        }
        return retCode;
    }

    /**
     *
     * {带参数修改}
     *
     * @param sql
     * @return
     * @author:LJ
     */
    protected int update(final String sql)
    {
        Connection con = null;
        Statement stmt = null;
        int retCode = 0;
        try
        {
            Class.forName(driverClassName);
            con = DriverManager.getConnection(url, username, password);
            stmt = con.createStatement();
            retCode = stmt.executeUpdate(sql);
        }
        catch (SQLException e)
        {
            throw new RuntimeException(e);
        }
        catch (ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        finally
        {
            DBUtil.closeQuietly(stmt);
            DBUtil.closeQuietly(con);
        }
        return retCode;
    }

    /**
     *
     * {批量处理}
     *
     * @param sql
     * @return
     * @author:LJ
     */
    protected int[] batchUpdate(final String[] sql)
    {
        Connection con = null;
        Statement stmt = null;
        int[] rowsAffected = new int[sql.length];
        try
        {
            Class.forName(driverClassName);
            con = DriverManager.getConnection(url, username, password);
            stmt = con.createStatement();
            for (int i = 0, n = sql.length; i < n; i++)
            {
                stmt.addBatch(sql[i]);
            }
            rowsAffected = stmt.executeBatch();
        }
        catch (SQLException e)
        {
            throw new RuntimeException(e);
        }
        catch (ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        finally
        {
            DBUtil.closeQuietly(stmt);
            DBUtil.closeQuietly(con);
        }
        return rowsAffected;
    }

    /**
     *
     * {带参数批量处理}
     *
     * @param sql
     * @return
     * @author:LJ
     */
    public int[] batchUpdate(final String sql, final BatchPreparedStatementSetter pss)
    {

        Connection con = null;
        PreparedStatement preparedStatement = null;
        int[] rowsAffected = null;
        try
        {
            Class.forName(driverClassName);
            con = DriverManager.getConnection(url, username, password);
            preparedStatement = con.prepareStatement(sql);
            for (int i = 0, n = pss.getBatchSize(); i < n; i++)
            {
                pss.setValues(preparedStatement, i);
                preparedStatement.addBatch();
            }
            rowsAffected = preparedStatement.executeBatch();
        }
        catch (SQLException e)
        {
            throw new RuntimeException(e);
        }
        catch (ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        finally
        {
            DBUtil.closeQuietly(preparedStatement);
            DBUtil.closeQuietly(con);
        }
        return rowsAffected;
    }
}

3.对外接口RowMapper.java

package com.dao;

import java.sql.ResultSet;
import java.sql.SQLException;

public interface RowMapper<E>
{
    /**
     *
     * {将结果集中的一行转化为JAVA对象}
     *
     * @param rs
     * @return
     * @author:LJ
     */
    public E map(ResultSet rs) throws SQLException;
}

4.批处理接口BatchPreparedStatementSetter.java

package com.dao;

import java.sql.PreparedStatement;
import java.sql.SQLException;

public interface BatchPreparedStatementSetter
{
    /**
     *
     * {设置参数值}
     *
     * @param preparedstatement
     * @param i
     * @throws SQLException
     * @author:LJ
     */
    public void setValues(PreparedStatement preparedstatement, int i) throws SQLException;

    /**
     *
     * {获取批处理个数}
     *
     * @return
     * @author:LJ
     */
    public int getBatchSize();
}

5.关闭资源DBUtil.java

package com.dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBUtil
{
    /**
     *
     * {关闭连接}
     *
     * @param con
     * @author:LJ
     */
    public static void closeQuietly(Connection con)
    {
        try
        {
            if (con != null)
            {
                con.close();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }

    /**
     *
     * {关闭Statement声明}
     *
     * @param stmt
     * @author:LJ
     */
    public static void closeQuietly(Statement stmt)
    {
        try
        {
            if (stmt != null)
            {
                stmt.close();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }

    /**
     *
     * {关闭结果集}
     *
     * @param rs
     * @author:LJ
     */
    public static void closeQuietly(ResultSet rs)
    {
        try
        {
            if (rs != null)
            {
                rs.close();
            }
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }
    }
}