CREATE TABLE t_user(
 uid CHAR(32) PRIMARY KEY,
 uname VARCHAR(40) NOT NULL,
 upassword VARCHAR(40) NOT NULL
);

CREATE TABLE t_student(
 sid CHAR(32) PRIMARY KEY,
 sname VARCHAR(40) NOT NULL,
 gender VARCHAR(6) NOT NULL,
 birthday CHAR(10),
 tellphone VARCHAR(15) NOT NULL,
 email VARCHAR(40), 
 description VARCHAR(500)
);

public class UserService {
 private UserDao userDao = new UserDao();

 public User query(User form) throws Exception{
 User user = userDao.query(form);

 //沒找到用戶
 if(user == null){
 throw new Exception("用戶名不存在");
 }

 //找到用戶了，但密碼不匹配
 if(!form.getUpassword().equals(user.getUpassword())){
 throw new Exception("密碼錯誤");
 }

 return user;
 }
}

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
 throws IOException, ServletException {
 //1.得到session
 //2.判斷session中是否有用戶,如果有，放行
 //3.否則轉到登錄頁面
 HttpServletRequest req = (HttpServletRequest)request;
 User user = (User)req.getSession().getAttribute("sessionUser");
 if(user != null){
 chain.doFilter(request, response);
 }else{
 HttpServletResponse resp = (HttpServletResponse)response;
 resp.sendRedirect(req.getContextPath() + "/index.jsp");
 } 
 }

public List<Student> query(Student s){
 try{
 StringBuilder sql = new StringBuilder("SELECT * FROM t_student WHERE 1=1");
 List<Object> params = new ArrayList<Object>();

 if(s.getSname() != null && !s.getSname().trim().isEmpty()){
 sql.append(" and sname like ?");
 params.add("%" + s.getSname() + "%");
 }

 if(s.getGender() != null && !s.getGender().trim().isEmpty()){
 sql.append(" and gender=?");
 params.add(s.getGender());
 }

 if(s.getTellphone() != null && !s.getTellphone().trim().isEmpty()){
 sql.append(" and tellphone like ?");
 params.add("%" + s.getTellphone() + "%");
 }

 if(s.getEmail() != null && !s.getEmail().trim().isEmpty()){
 sql.append(" and email like ?");
 params.add("%" + s.getEmail() + "%");
 }

 return qr.query(sql.toString(), 
 new BeanListHandler<Student>(Student.class),
 params.toArray());
 }catch (Exception e) {
 throw new RuntimeException(e);
 }
}

public class PageBean <T>{
 private Integer pageCode;//當前頁碼
 private Integer pageSize;//每頁數(shù)據(jù)大小
 private Integer totalRecord;//總記錄
 private List<T> beanList;//當前頁的記錄，定義成泛型為了以后直接用
 private String url;//多條件組合查詢時url后的條件

 //返回總頁數(shù)
 public Integer getTotalPage(){
 int tp = totalRecord/pageSize;
 return totalRecord%pageSize==0 ? tp : tp+1;
 }
 ...//屬性的get，set方法
 ...
}

<center>
第${pb.pageCode }頁/共${pb.totalPage }頁
<a href="${pb.url }&pc=1" rel="external nofollow" > 首頁</a>
<c:if test="${pb.pageCode > 1 }">
<a href="${pb.url }&pc=${pb.pageCode-1 }" rel="external nofollow" >上一頁</a>
</c:if>
<!-- 頁碼表 計算begin end-->
<c:choose>
 <c:when test="${pb.totalPage<=10 }">
 <c:set var="begin" value="1"></c:set>
 <c:set var="end" value="${pb.totalPage }"></c:set>
 </c:when>
 <c:otherwise>
 <%-- 計算公式 --%>
 <c:set var="begin" value="${pb.pageCode-5 }"></c:set>
 <c:set var="end" value="${pb.pageCode+4 }"></c:set>
 <%--- 頭溢出 --%>
 <c:if test="${begin<1 }">
 <c:set var="begin" value="1"></c:set>
 <c:set var="end" value="10"></c:set>
 </c:if>
 <%-- 尾溢出 --%>
 <c:if test="${end> pb.totalPage}">
 <c:set var="begin" value="${pb.totalPage-9 }"></c:set>
 <c:set var="end" value="${pb.totalPage }"></c:set>
 </c:if>
 </c:otherwise>
</c:choose>
<%-- 循環(huán)顯示頁碼列表 --%>
<c:forEach var="i" begin="${begin }" end="${end }">
 <c:choose>
 <c:when test="${i eq pb.pageCode }">
 [${i }]
 </c:when>
 <c:otherwise>
 <a href="${pb.url }&pc=${i }">[${i }]</a>
 </c:otherwise>
 </c:choose> 
</c:forEach>

<c:if test="${pb.pageCode < pb.totalPage }">
<a href="${pb.url }&pc=${pb.pageCode+1 }">下一頁</a>
</c:if>
<a href="${pb.url }&pc=${pb.totalPage }">尾頁</a>
</center>

public PageBean<Student> query(Student s,int pc,int ps){
 try{
 PageBean<Student> pb = new PageBean<Student>();
 pb.setPageCode(pc);
 pb.setPageSize(ps);

 /*
 * 查詢出總記錄
 */
 StringBuilder numSql = new StringBuilder("SELECT COUNT(*) FROM t_student");
 StringBuilder whereSql = new StringBuilder(" WHERE 1=1");
 List<Object> params = new ArrayList<Object>();

 if(s.getSname() != null && !s.getSname().trim().isEmpty()){
 whereSql.append(" and sname like ?");
 params.add("%" + s.getSname() + "%");
 }

 if(s.getGender() != null && !s.getGender().trim().isEmpty()){
 whereSql.append(" and gender=?");
 params.add(s.getGender());
 }

 if(s.getTellphone() != null && !s.getTellphone().trim().isEmpty()){
 whereSql.append(" and tellphone like ?");
 params.add("%" + s.getTellphone() + "%");
 }

 if(s.getEmail() != null && !s.getEmail().trim().isEmpty()){
 whereSql.append(" and email like ?");
 params.add("%" + s.getEmail() + "%");
 }

 Number number = (Number)qr.query(numSql.append(whereSql).toString(), 
 new ScalarHandler(),params.toArray());
 int totalRecord = number.intValue();
 pb.setTotalRecord(totalRecord);

 /*
 * 得到beanList結果集
 */
 StringBuilder sql = new StringBuilder("SELECT * FROM t_student");
 StringBuilder limitSql = new StringBuilder(" limit ?,?");
 params.add((pc-1)*ps);
 params.add(ps);
 List<Student> students = qr.query(sql.append(whereSql).append(limitSql).toString(),
 new BeanListHandler<Student>(Student.class),params.toArray());
 pb.setBeanList(students);
 return pb;
 }catch (Exception e) {
 throw new RuntimeException(e);
 }
}