下面这个查询， sql 拼接应该没错吧，主要是 jdbcTemplate.query(sql, rowMapper, q, page, perPage); 这个东西怎么传

一开始我想是用 if 判断，如果用 if 判断，3个参数加起来可有 N 种组合呀，如果再多几个参数不就悲剧了，这样的一般怎么写？

 java


 @Override
public List<Pin> searchPins(String q, String category, String c, Integer page, Integer perPage) {
    q = "%" + q + "%";

    if(perPage == null) {
        perPage = 20;
    }

    if(page == null || page == 0) {
        page = 0;
    } else {
        page = (page - 1) * perPage;
    }

    String arg0 = "";
    String arg1 = "";

    if(!StringUtils.isBlank(category)) {
        arg0 = arg0 + ", tz_board b";
        arg1 = arg1 + " AND b.deleting = 0 AND p.board_id = b.board_id AND b.category_id = ?";
        q = q + ", " + category;
    }

    if(!StringUtils.isBlank(c)) {
        arg0 = arg0 + ", tz_file f";
        arg1 = arg1 + " AND p.file_id = f.file_id AND f.theme = ?";
        q = q + ", " + c;
    }

    String sql = "SELECT p.* FROM tz_pin p" + arg0 + " WHERE p.deleting = 0 AND p.is_private = 0 AND p.raw_text LIKE ?" + arg1 + " ORDER BY p.pin_id DESC LIMIT ?,?";
    RowMapper<Pin> rowMapper = new BeanPropertyRowMapper<Pin>(Pin.class);
    System.out.println(sql);
    System.out.println(q);
    System.out.println(page);
    System.out.println(perPage);
    return jdbcTemplate.query(sql, rowMapper, q, page, perPage);
}

笨方法：如果在多几个参数可能就悲剧啦

 java


 @Override
    public List<Pin> searchPins(String q, String category, String c, Integer page, Integer perPage) {
        q = "%" + q + "%";

        if(perPage == null) {
            perPage = 20;
        }

        if(page == null || page == 0) {
            page = 0;
        } else {
            page = (page - 1) * perPage;
        }

        String arg0 = "";
        String arg1 = "";

        if(!StringUtils.isBlank(category)) {
            arg0 = arg0 + ", tz_board b";
            arg1 = arg1 + " AND b.deleting = 0 AND p.board_id = b.board_id AND b.category_id = ?";
        }

        if(!StringUtils.isBlank(c)) {
            arg0 = arg0 + ", tz_file f";
            arg1 = arg1 + " AND p.file_id = f.file_id AND f.theme = ?";
        }


        String sql = "SELECT p.* FROM tz_pin p" + arg0 + " WHERE p.deleting = 0 AND p.is_private = 0 AND p.raw_text LIKE ?" + arg1 + " ORDER BY p.pin_id DESC LIMIT ?,?";
        RowMapper<Pin> rowMapper = new BeanPropertyRowMapper<Pin>(Pin.class);

        if(!StringUtils.isBlank(category) && StringUtils.isBlank(c)) {
            return jdbcTemplate.query(sql, rowMapper, q, category, page, perPage);
        } else if(!StringUtils.isBlank(c) && StringUtils.isBlank(category)) {
            return jdbcTemplate.query(sql, rowMapper, q, c, page, perPage);
        } else if(!StringUtils.isBlank(c) && !StringUtils.isBlank(category)) {
            return jdbcTemplate.query(sql, rowMapper, q, category, c, page, perPage);
        }

        return jdbcTemplate.query(sql, rowMapper, q, page, perPage);
    }