一个dao层有很多功能
public interface UserDao {
//获取总记录数
long bookReadCount();
//分页查询用户
List<User> userList(PageBean pageBean);
//获取用户列表（分页显示）
boolean findUser(String userName);
//根据id查看一个用户
User findUser(Integer id);
//增加用户
boolean userAdd(User user);
//修改用户
boolean userUpdate(User user);
//根据id删除一个用户
boolean delUser(int id);
//根据一组id字符串批量删除用户
boolean batDelUser(String id);
//用户登录
User userLogin(User user);
}
初学者一个功能对应一个servlet，一套curd操作下来4，5个servlet很正常
用生成的doGet，doPost只能实现一个功能
@WebServlet("/UserAddServlet") public class UserAddServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req,resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String userName = req.getParameter("userName"); String userPwd = req.getParameter("userPwd"); String userSex = req.getParameter("userSex"); String userPhone = req.getParameter("userPhone"); String userEmail = req.getParameter("userEmail"); String userAddress = req.getParameter("userAddress"); User user = new User(); user.setUserName(new String(userName.getBytes("ISO-8859-1"),"utf-8")); user.setUserPwd(userPwd); user.setUserSex(new String(userSex.getBytes("iso-8859-1"),"utf-8")); user.setUserPhone(userPhone); user.setUserEmail(userEmail); user.setUserAddress(new String(userAddress.getBytes("iso-8859-1"),"utf-8")); UserDao dao = new UserDao(); dao.addUser(user); req.getRequestDispatcher("UserShowServlet").forward(req,resp); } }
把一个dao层的功能放到一个servlet里面，有两种思路
第一种配置xml地址，进行条件判断，但是if太多了
@WebServlet(name = "actionServlet",urlPatterns = {"/userByteId","/allUser","/addUser","/updateUser","/deleteUser"})
这个注解等于xml里面的<servlet-mapping>
<!-- <servlet-mapping>-->
<!-- <servlet-name>actionServlet</servlet-name>-->
<!-- <url-pattern>/allUser</url-pattern>-->
<!-- <url-pattern>/dabo/allUser</url-pattern>-->
<!-- <url-pattern>/userByteId</url-pattern>-->
<!-- <url-pattern>/addUser</url-pattern>-->
<!-- <url-pattern>/updateUser</url-pattern>-->
<!-- <url-pattern>/deleteUser</url-pattern>-->
<!-- </servlet-mapping>-->
public class actionServlet extends HttpServlet {
UserDao userDao = new UserDao();
User user = new User();
//如何区分发过来的请求，并通过请求调用不通方法处理
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取请求的url地址
String path = req.getRequestURI();
System.out.println(path);
//获取最后一个斜杠的下标
int index = path.lastIndexOf("/");
//截取分发的请求
String relaPath = path.substring(index + 1);
System.out.println("relaPath=" + relaPath);
//根据不同的请求，调用不同的方法处理
if (relaPath.equals("login")) {
try {
login(req,resp);
} catch (Exception e) {
e.printStackTrace();
}
}else if (relaPath.equals("addUser")){
try {
addUser(req,resp);
} catch (Exception e) {
e.printStackTrace();
}
} else if (relaPath.equals("updateUser")) {
try {
updateUser(req,resp);
} catch (Exception e) {
e.printStackTrace();
}
} else if (relaPath.equals("deleteUser")) {
try {
deleteUser(req,resp);
} catch (Exception e) {
e.printStackTrace();
}
} else if (relaPath.equals("userByteId")) {
try {
userByteId(req,resp);
} catch (Exception e) {
e.printStackTrace();
}
}else if (relaPath.equals("allUser")) {
try {
allUser(req,resp);
} catch (Exception e) {
e.printStackTrace();
}
}
}public void addUser(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
req.setCharacterEncoding("utf-8");
resp.setCharacterEncoding("utf-8");
String userName = req.getParameter("userName");
String userPwd = req.getParameter("userPwd");
String userSex = req.getParameter("userSex");
String userPhone = req.getParameter("userPhone");
String userEmail = req.getParameter("userEmail");
String userAddress = req.getParameter("userAddress");
user.setUserName(userName);
user.setUserPwd(userPwd);
user.setUserSex(userSex);
user.setUserPhone(userPhone);
user.setUserEmail(userEmail);
user.setUserAddress(userAddress);
userDao.addUser(user);
req.getRequestDispatcher("allUser").forward(req,resp);
}
public void updateUser(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
req.setCharacterEncoding("utf-8");
resp.setCharacterEncoding("utf-8");
String userName = req.getParameter("userName");
String userPwd = req.getParameter("userPwd");
String userSex = req.getParameter("userSex");
String userPhone = req.getParameter("userPhone");
String userEmail = req.getParameter("userEmail");
String userAddress = req.getParameter("userAddress");
String id = req.getParameter("id");
user.setUserName(userName);
user.setUserPwd(userPwd);
user.setUserSex(userSex);
user.setUserPhone(userPhone);
user.setUserEmail(userEmail);
user.setUserAddress(userAddress);
user.setId(Integer.valueOf(id));
userDao.updateUser(user);
req.getRequestDispatcher("allUser").forward(req,resp);
}
public void deleteUser(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
String idStr = req.getParameter("id");
if (idStr != null && idStr != "") {
int id = Integer.valueOf(idStr);
userDao.deleteUser(id);
}
req.getRequestDispatcher("allUser").forward(req,resp);
}
public void userByteId(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
String idStr = req.getParameter("id");
if (idStr != null && idStr != "") {
int id = Integer.valueOf(idStr);
user = userDao.selectUserById(id);
req.setAttribute("users",user);
}
req.getRequestDispatcher("updateUser.jsp").forward(req,resp);
}
public void allUser(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
List<User> lists = userDao.getAllUser();
req.setAttribute("lists",lists);
req.getRequestDispatcher("user.jsp").forward(req,resp);
}
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req,resp);
}
}
第二种，创建一个父类BaseServlet
用反射重写service方法，子类继承截取后缀直接调用对应的方法
1 public class BaseServlet extends HttpServlet {
2
3 @Override
4 protected void service(HttpServletRequest request, HttpServletResponse response)
5 throws ServletException, IOException {
6 // 1、获得方法名称
7 String methodName = request.getParameter("method");
8 Method method = null;
9
10 // 2、通过方法名和方法所需要的参数获得Method对象
11 try {
12 method = this.getClass().getMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);
13 } catch (Exception e) {
14 throw new RuntimeException("调用的方法：" + methodName + "不存在", e);
15 }
16
17 // 3、通过Method对象调用方法
18 try {
19 String result = (String) method.invoke(this, request, response);
20 if (result != null && result.trim().length() > 0) {// 如果返回的result不为空
21 int index = result.indexOf(":");// 获得第一个冒号的位置
22 if (index == -1) {// 如果没有冒号，就使用转发
23 request.getRequestDispatcher(result).forward(request, response);
24 } else {// 如果有冒号
25 String start = result.substring(0, index);// 截取前缀
26 String path = result.substring(index + 1);// 截取路径
27 if (start.equalsIgnoreCase("f")) {// 前缀为f表示使用转发
28 request.getRequestDispatcher(path).forward(request, response);
29 } else if (start.equalsIgnoreCase("r")) {// 前缀为r表示使用重定向
30 response.sendRedirect(request.getContextPath() + path);
31 }
32 }
33 }
34 } catch (Exception e) {
35 throw new RuntimeException(e);
36 }
37 }
38 }
1 public class UserManageServlet extends BaseServlet {
2 private static final String USERLIST_PATH = "userManage/userList.jsp";//用户列表页面地址
3 private static final String USERADD_PATH = "userManage/userAdd.jsp";//用户增加页面地址
4 private static final String USEREDIT_PATH = "userManage/userEdit.jsp";//用户修改页面地址
5 private static final String USERDETAIL_PATH = "userManage/userDetail.jsp";//用户修改页面地址
6
7 public void userList(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
8 UserDao dao = new UserDaoImpl();
9 int curPage = 1;
10 String page = req.getParameter("page");
11 if (page != null) {
12 curPage = Integer.parseInt(page);
13 }
14 //获取xml中设置的每页显示大小参数
15 int maxSize = Integer.parseInt(req.getServletContext().getInitParameter("maxPageSize"));
16 PageBean pageBean = new PageBean(curPage, maxSize, dao.bookReadCount());
17 req.setAttribute("userList", dao.userList(pageBean));
18 req.setAttribute("pageBean", pageBean);
19 req.getRequestDispatcher(USERLIST_PATH).forward(req, resp);
20 }
21
22 public void userDel(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
23 int id = Integer.parseInt(req.getParameter("id"));
24 UserDao dao = new UserDaoImpl();
25 if (dao.delUser(id)) {
26 req.setAttribute("userMessage", "用户已删除");
27 } else {
28 req.setAttribute("userMessage", "用户删除失败");
29 }
30 //用户删除成功失败都跳转到用户列表页面
31 userList(req, resp);
32 }
33
34 public String userAddjsp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
35 return USERADD_PATH;
36 }
37
38 public void userAdd(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
39 System.out.println("三大佛充当反锁车方所陈红戳地方戳");
40 UserDao ad=new UserDaoImpl();
41 User user=new User(
42 request.getParameter("userName"),
43 request.getParameter("passWord"),
44 request.getParameter("name"),
45 request.getParameter("sex"),
46 Integer.parseInt(request.getParameter("age")),
47 request.getParameter("tell"),
48 request.getParameter("address"));
49 user.setEnabled("y");//默认添加的用户启用
50 //添加之前判断用户名是否在库中存在
51 if(new AdminDaoImpl().findUser(user.getUserName())){
52 request.setAttribute("userMessage", "用户添加失败！用户名已存在");
53 request.getRequestDispatcher(USERADD_PATH).forward(request, response);
54 }else{
55 //执行dao层添加操作
56 if(ad.userAdd(user)){
57 request.setAttribute("userMessage", "用户添加成功！");
58 userList(request, response);//通过servlet中listUser跳到用户列表
59 }else{
60 request.setAttribute("userMessage", "用户添加失败！");
61 request.getRequestDispatcher(USERADD_PATH).forward(request, response);
62 }
63 }
64 }
65
66 public void datail(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
67 String id=request.getParameter("id");
68 UserDao ud=new UserDaoImpl();
69 request.setAttribute("userInfo",ud.findUser(Integer.valueOf(id)));//这里回去是User对象
70 request.getRequestDispatcher(USERDETAIL_PATH).forward(request, response);
71
72 }
73 public void userEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
74 String id=request.getParameter("id");
75 UserDao ud=new UserDaoImpl();
76 request.setAttribute("userInfo",ud.findUser(Integer.valueOf(id)));//这里回去是User对象
77 request.getRequestDispatcher(USEREDIT_PATH).forward(request, response);
78
79 }
80
81 public void userUpdate(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
82 User user=new User(
83 Integer.parseInt(request.getParameter("userId")),
84 request.getParameter("passWord"),
85 request.getParameter("name"),
86 request.getParameter("sex"),
87 Integer.parseInt(request.getParameter("age")),
88 request.getParameter("tell"),
89 request.getParameter("address"),
90 request.getParameter("enabled"));
91 UserDao ud=new UserDaoImpl();
92 if(ud.userUpdate(user)) {
93 request.setAttribute("userMessage", "用户更新成功");
94 userList(request, response);//通过servlet中listUser跳到用户列表
95 }else {
96 //更新失败跳转到修改页面
97 request.setAttribute("userMessage", "用户更新失败");
98 request.setAttribute("userInfo", ud.findUser(Integer.valueOf(user.getUserId())));//这里回去是Admin对象
99 request.getRequestDispatcher(USEREDIT_PATH).forward(request, response);
100 }
101 }
102
103 public void userBatDel(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
104 String ids=request.getParameter("ids");
105 UserDao ud=new UserDaoImpl();
106
107 if(ud.batDelUser(ids)) {
108 request.setAttribute("userMessage", "用户已批量删除");
109 }else {
110 request.setAttribute("userMessage", "用户批量删除失败");
111 }
112 //用户删除成功失败都跳转到用户列表页面
113 userList(request, response);//通过servlet中listUser跳到用户列表
114 }
115 }
不过这种写法，直接跳转jsp页面会报错，需要写一个String方法跳转
public String userAddjsp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
return USERADD_PATH;
}