我的java web架构方案_JAVA_编程开发_程序员俱乐部

class="java">
//业务逻辑代码片段
private String word;
    private String area;
    private String type;
    private Integer year;
    private String order;
    private Integer page;

@NotNull
@Min(0)
private Integer id;

public void list(HttpServletRequest req, HttpServletResponse res) throws ... {
//获得请求参数处理工具类实例，这里直接从上下文读取，你也可以使用spring或者自行实现依赖注入
        RequestParameterUtil paramUtil = (RequestParameterUtil) req.getServletContext().getAttribute("requestParameterUtil");
//获得消息对象
        Messages messages = (Messages) req.getAttribute("messages");
        String[] paramNames = {"word", "area", "type", "year", "order", "page"};
//请求参数工具类根据paramNames指定的参数数组利用反射依照命名约定绑定到this对象，本例为查询操作。当然，对于insert操作，绑定到javaBean对象更快捷方便。
//然后工具类自动执行java标准的基于注解的数据合法性验证validate
//bind()方法返回布尔值，标示是否存在绑定或者验证错误，messages为消息对象，保存所有分级别的消息
        paramUtil.bind(req, this, paramNames, messages);

//定义命名参数形式的分页url
        String paginationLink = "/xxx/yyy?zz=abc&aaa=efg&page=:page";
...
        try (Connection conn = HdgangDataSource.getConnection(HostFactory.getHost())) {
//Pagination为查询分页工具类，cntRowPerPage参数为每页记录条数，第三个参数为满足条件的总记录数，这里先留空，最后一个参数指定分页命名参数
            Pagination pagination = new Pagination(page, cntRowPerPage, null, paginationLink, ":page");
//DAO方法
            List<Movie> movieList = MovieDAO.getList(conn, word, order, pagination);
//可以换成依赖注入。pagination 为分页对象，视图可直接配合模板一行代码渲染分页模块
            req.setAttribute("movieList", movieList);
            req.setAttribute("pagination", pagination);
        }
//可以返回字符串消息，交由控制器处理跳转
        req.getRequestDispatcher("/cult/list.jsp").forward(req, res);
    }


//get set 方法省略

//DAO方法

public static List<Movie> getList(Connection conn, String word, String order, Pagination pagination)
            throws ... {
//业务逻辑为mysql全文搜索，可略过不看。依据查询条件拼接复杂sql，myBatis实现的话比较别扭。
        String select = "select `id`,`imdbid`,`name`,`year`,`duration`,`aliases`,`directors`,`actors`,`tags`,`intro`"
                + ",`areas`,`types`,`score`,`date`,`update`,`state` from `movie` ";
        String selectCnt = "select count(*) from `movie` ";

        String conditions = "";
        String fulltext = "";
        if (word != null && !word.trim().isEmpty()) {
            word = word.trim();
            fulltext = Tool.encode(word, true, "+");
            conditions = " where match(`fulltext`) against(:fulltext IN BOOLEAN MODE) ";
        }

        String orders;
        switch (order) {
            case "score":
                orders = " order by `score` desc ";
                break;
            case "sdate":
                orders = " order by `date` desc ";
                break;
            default:
                orders = " order by `update` desc,`date` desc ";
                break;
        }
//通过map绑定命名参数（类似于 :xxx），也支持通过javaBean绑定
        Map<String, Object> paramMap = new HashMap<>();
        paramMap.put("fulltext", fulltext);
        
        String sql0 = selectCnt + conditions + ";";
//DAO为数据库工具类，getScalar获取符合条件的记录条数
        long rowTotalCnt = DAO.getScalar(conn, sql0, paramMap);
        List<Movie> movieList = null;
        if (rowTotalCnt > 0) {
//将查询得到的记录条数set到pagination
            pagination.setRowTotalCnt(rowTotalCnt);
            String sql = select + conditions + orders + " limit " + pagination.getOffset() + "," + pagination.getRowCnt() + ";";
//getBeanList 获得查询得到的分页记录，getBeanList重载支持javaBean和Map绑定命名参数
            movieList = DAO.getBeanList(conn, sql, paramMap, Movie.class);
        }
        return movieList;
    }