Java 多条件查询

 

首先在dao层写一个普通的查询语句：

private String findPage = "SELECT * from bt_assayitemstable where 1=1 ";

在语句后面加上where1=1，是为了后面更好的拼接条件进行查询，避免在查询的时候直接拼接成

where and … 而报语法错误，下面是实现的方法：

public List findPage(String assayItemsNumber,

            String assayItemsName, String chineseName, int start, int PageSize) {

    List list = null;

    con = DbUtil.getConnection();

    try {

        StringBuffer sql = new  StringBuffer();

        if(Tools.isNotNull(assayItemsNumber)){

                sql.append("and AssayItemsNumber like '%"+ assayItemsNumber + "%'");

        }

        if(Tools.isNotNull(assayItemsName)){

                sql.append("and AssayItemsName like '%"+ assayItemsName + "%'");

        }

        if(Tools.isNotNull(chineseName)){

                sql.append("and ChineseName like '%"+ chineseName + "%'");

        }

        sql.append(" LIMIT ?,?");

        findPage+=sql;

        ps = con.prepareStatement(findPage);

        ps.setInt(1, start);

        ps.setInt(2, PageSize);

        rs = ps.executeQuery();

        list = DbUtil.getResult(rs, BtAssayItems.class);

        } catch (SQLException e) {

        e.printStackTrace();

        }finally{

            DbUtil.close(con, ps, rs);

        }

        return list;

    }

然后再去service包内写它接口与实现类，这里就不多叙述，servlet那边通过

request.getParameter接收jsp页面传过来的值，如果是int要通过Integer转换为int型。

我这里使用了JQ.bsgrid进行分页，

下面是对应servlet层的代码：

private void getlist(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String strpageSize = request.getParameter("pageSize");

        String strcurPage = request.getParameter("curPage");

        IAssayItemsService assayItemsService = new AssayItemsServiceImpl();

        String assayItemsNumber = request.getParameter("assayItemsNumber");

        String assayItemsName = request.getParameter("assayItemsName");

        String chineseName = request.getParameter("chineseName");



        Bsgrid bsgrid = new Bsgrid<>();

        if (Tools.isNum(strcurPage) && Tools.isNum(strpageSize)) {

            int pageSize = Integer.parseInt(strpageSize);

            int curPage = Integer.parseInt(strcurPage);

            int start = (curPage - 1) * pageSize;

           

List list = assayItemsService.findPage(assayItemsNumber, assayItemsName, chineseName, start, pageSize);

int totalRows = assayItemsService.getTotalRow(assayItemsNumber, assayItemsName, chineseName);

            bsgrid.setCurPage(curPage);

            bsgrid.setTotalRows(totalRows);

            bsgrid.setSuccess(true);

            bsgrid.setData(list);

        } else {

            bsgrid.setSuccess(false);

        }

        JSONObject jsonObject = JSONObject.fromObject(bsgrid);

       

        PrintWriter out = response.getWriter();

        out.write(jsonObject.toString());

        out.close();

    }

下面是jsp页面对应的js代码

function querys(){

       var assayItemsNumber = $("#qassayItemsNumber").val();

       if (assayItemsNumber == undefined || assayItemsNumber=="") {

                assayItemsNumber = "";

                } 

        var assayItemsName = $("#qassayItemsName").val();

        if (assayItemsName == undefined || assayItemsName=="") {

                assayItemsNames = "";

                } 

        var chineseName = $("#qchineseName").val();

        if (chineseName == undefined || chineseName=="") {

                chineseName = "";

                }   tbAssayItem.search({ assayItemsNumber:assayItemsNumber,assayItemsName:

assayItemsName,chineseName:chineseName});        

    }

    然后再bsgrid初始化表格时调用这个方法，和在点击查询按钮的时候调用该方法即可实现

多条件查询。