【DRP】—【SQL】批量删除

    /**
     * 批量删除用户
     * 
     * 采用一条语句完成删除
     * 只提交一次
     * 
     * 采用Statement拼串方式
     * delete from t_user where user_id in ('aaaa', 'afff', 'eeee')
     * @param userIds
     */
    public void delUser(String[] userIds) {
        StringBuilder sbStr = new StringBuilder();
        for (int i=0; i<userIds.length; i++) {
            sbStr.append("'")
            .append(userIds[i])
            .append("'")
            .append(",");
        }
        String sql = "delete from t_user where user_id in (" + sbStr.substring(0, sbStr.length() - 1) + ")";
        System.out.println("UserManager.delUser() -->>" + sql);
        Connection conn = null;
        Statement stmt = null;
        try {
            conn = DbUtil.getConnection();
            stmt = conn.createStatement();
            stmt.executeUpdate(sql);
        }catch(SQLException e) {
            e.printStackTrace();
        }finally {
            DbUtil.close(stmt);
            DbUtil.close(conn);
        }
    }

/**
     * 批量删除用户
     * 
     * 采用一条语句完成删除
     * 只提交一次
     * 
     * 采用PreparedStatement占位符方式
     * 
     * delete from t_user where user_id in (?, ?, ?)
     * @param userIds
     */
    public void delUser(String[] userIds) {
        StringBuilder sbStr = new StringBuilder();
        for (int i=0; i<userIds.length; i++) {
            sbStr.append("?");
            if (i < (userIds.length - 1)) {
                sbStr.append(",");
            }
        }
        String sql = "delete from t_user where user_id in (" + sbStr.toString()  +  ")";
        System.out.println("UserManager.delUser() -->>" + sql);
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DbUtil.getConnection();
            pstmt = conn.prepareStatement(sql);
            for (int i=0; i<userIds.length; i++) {
                pstmt.setString(i + 1, userIds[i]);
            }
            pstmt.executeUpdate();
        }catch(SQLException e) {
            e.printStackTrace();
        }finally {
            DbUtil.close(pstmt);
            DbUtil.close(conn);
        }
    }    

JDBC 笔记3 通过PreparedStatement 对数据库进行增删改查

总结：不断提高自己的编程效率！~~~~~