小型人口普查系统2

人口普查系统的查询方法：

1.通过教育程度进行查询

public class QueryByEducationServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String education = req.getParameter("education");
        CensusDaoImpl c = new CensusDaoImpl();
        List<Census> censuses = c.fuzzyQueryByName(education);
        req.setAttribute("list", censuses);
        //System.out.println(censuses);
        if (censuses == null){
            req.getRequestDispatcher("query_wrong.jsp").forward(req, resp);
        } else {
            req.getRequestDispatcher("query_success.jsp").forward(req, resp);
        }
    }
}

2.通过姓名进行查找

public class QueryByNameServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String username = req.getParameter("username");
        CensusDaoImpl c = new CensusDaoImpl();
        List<Census> censuses = c.fuzzyQueryByName(username);
        HttpSession session = req.getSession();
        req.setAttribute("list", censuses);
        //System.out.println(censuses);
        if (censuses == null){
            req.getRequestDispatcher("query_wrong.jsp").forward(req, resp);
        } else {
            req.getRequestDispatcher("query_success.jsp").forward(req, resp);
        }
    }
}

3.通过宗教进行查找

public class QueryByNameServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String username = req.getParameter("username");
        CensusDaoImpl c = new CensusDaoImpl();
        List<Census> censuses = c.fuzzyQueryByName(username);
        HttpSession session = req.getSession();
        req.setAttribute("list", censuses);
        //System.out.println(censuses);
        if (censuses == null){
            req.getRequestDispatcher("query_wrong.jsp").forward(req, resp);
        } else {
            req.getRequestDispatcher("query_success.jsp").forward(req, resp);
        }
    }
}

4.通过性别进行查找

public class QueryBySexServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String sex = req.getParameter("sex");
        CensusDaoImpl c = new CensusDaoImpl();
        List<Census> censuses = c.fuzzyQueryByName(sex);
        req.setAttribute("list", censuses);
        if (censuses == null)
            req.getRequestDispatcher("query_wrong.jsp").forward(req, resp);
        else
            req.getRequestDispatcher("query_success.jsp").forward(req,resp);
    }
}

 

 

基本的增删改查操作，我都写到一个BaseDao中了。我写的这个是最麻烦的一种，学过德鲁伊或者是Spring框架的略过。。。

public class BaseDao<T> {
    public int update(Connection conn, String sql, Object...args){
        PreparedStatement ps = null;
        try{
            ps = conn.prepareStatement(sql);
            for (int i = 0; i < args.length; i++) {
                ps.setObject(i+1, args[i]);
            }
            return ps.executeUpdate();
        } catch(Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(null, ps);
        }
        return 0;
    }

    //通用的查询操作
    public <T>T getInstance(Connection conn, Class<T> tClass, String sql, Object...args) {
        PreparedStatement ps=null;
        ResultSet rs=null;
        try {
            ps = conn.prepareStatement(sql);
            for (int i = 0; i < args.length; i++) {
                ps.setObject(i+1, args[i]);
            }
            rs = ps.executeQuery();
            ResultSetMetaData metaData = rs.getMetaData();
            int columnCount = metaData.getColumnCount();
            if (rs.next()){
                T t = tClass.newInstance();
                for (int i = 0; i < columnCount; i++) {
                    Object columValue = rs.getObject(i + 1);
                    String columnLabel = metaData.getColumnLabel(i + 1);

                    Field field = tClass.getDeclaredField(columnLabel);
                    field.setAccessible(true);
                    field.set(t, columValue);
                }
                return t;
            }
        } catch (Exception e){
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(null, ps, rs);
        }
        return null;
    }

    public <T> List<T> getForList(Connection conn, Class<T> tClass, String sql, Object...args) {
        PreparedStatement ps=null;
        ResultSet rs = null;
        try {
            ps = conn.prepareStatement(sql);
            for (int i = 0; i < args.length; i++) {
                ps.setObject(i+1, args[i]);
            }
            rs = ps.executeQuery();
            ResultSetMetaData metaData = rs.getMetaData();
            int columnCount = metaData.getColumnCount();
            ArrayList<T> list = new ArrayList<>();
            while(rs.next()){
                T t = tClass.newInstance();
                for (int i = 0; i < columnCount; i++) {
                    Object columValue = rs.getObject(i + 1);
                    String columnLabel = metaData.getColumnLabel(i + 1);

                    Field field  = tClass.getDeclaredField(columnLabel);
                    field.setAccessible(true);
                    field.set(t, columValue);
                }
                list.add(t);
            }
            return list;
        } catch(Exception e){
            e.printStackTrace();
        } finally {
            JDBCUtils.closeResource(null, ps,rs);
        }
        return null;
    }
}