servlet2 单元测试、转发、重定向

java小小小小栈 2020-12-20

193

解决服务端接收数据乱码问题。服务器默认采用 ISO8859-1 编码响应内容。

// 1
req.setCharacterEncoding("utf-8");
// 2
    byte[] bytes = req.getParameter("username").getBytes("iso-8859-1");
    System.out.println("username:" + new String(bytes,0,bytes.length,"utf-8"));

解决服务端发送到客户端数据乱码问题。

// 1 text/html,响应数据类型;
     resp.setContentType("text/html;charset=utf8;");
     
// 2
     resp.setCharacterEncoding("utf-8");
     resp.setHeader("Content-type","text/html;charset=utf8");

单元测试。

src 同级目录创建 test 文件夹，右键 -> Mark Directory as ->Sources Root，文件名采用测试的模块名 + Test。

转发。转发的作用在服务器端，将请求发送给服务器上的其他资源，以共同完成一次请求的处理。使用forward跳转时，是在服务器内部跳转，地址栏不发生变化，属于同一次请求。

request.getRequestDispatcher(“/目标URL-pattern”).forward(request, response);
// 存数据
request.setAttribute(key,value);
// 取数据
request.getAttribute(key);

重定向。重定向作用在客户端，客户端将请求发送给服务器后，服务器响应给客户端一个新的请求地址，客户端重新发送新请求。

重定向可以指向任何的资源，包括当前应用程序中的其他资源、同一个站点上的其他应用程序中的资源、其他站点的资源。

response.sendRedirect(“目标URI”);
// 带数据
response.sendRedirect(“目标URI?username=tom&ps=123”);
// 接收数据
request.getParameter(“username”);

servlet 用户管理系统。

目录结构。

public class AddUserServlet extends HttpServlet {


    private IUserService userService = new UserServiceImpl();


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf8");


        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String age = req.getParameter("age");
        String sex = req.getParameter("sex");


        User user = new User();
        user.setUsername(username);
        user.setPassword(password);
        user.setAge(Integer.valueOf(age));
        user.setSex(Integer.valueOf(sex));
        int i = userService.AddUser(user);
        if (i == 0) {
            resp.getWriter().write("添加失败");
        } else {
            resp.getWriter().write("添加成功");
            resp.getWriter().write("<br><a href=\"GetUserListServlet\">查询所有用户</a>");
        }
    }
}






public class DeleteUserServlet extends HttpServlet {


    private IUserService userService = new UserServiceImpl();


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf8");


        String username = req.getParameter("username");


        int i = userService.DeleteUser(username);
        if (i == 0) {
            resp.getWriter().write("删除失败");
        } else {
            resp.getWriter().write("删除成功");
            resp.getWriter().write("<br><a href=\"GetUserListServlet\">查询所有用户</a>");
        }
    }
}




public class GetUserListServlet extends HttpServlet {


    private IUserService userService = new UserServiceImpl();


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf8");


        System.out.println("查询所有的用户:" + req);


        List<User> userList = userService.getUserList();


        // 转发数据
        req.setAttribute("userList",userList);
        // 转发对象
        req.getRequestDispatcher("ViewUserServlet").forward(req,resp);


        // 重定向 最好不带参数
        resp.sendRedirect("ViewUserServlet?username=zs&password=123");
        resp.sendRedirect("http://www.baidu.com");
    }
}




public class LoginUserServlet extends HttpServlet {


    private IUserService userService = new UserServiceImpl();


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf8");


        String username = req.getParameter("username");
        String password = req.getParameter("password");


        User user = userService.login(username, password);


        if (user == null) {
            resp.getWriter().write("用户名或密码错误..");
        } else {
            resp.getWriter().write("欢迎【" + req.getRemoteAddr() + username + "】登陆");
            resp.getWriter().write("<br><a href=\"GetUserListServlet\">查询所有用户</a>");
        }


    }
}






public class SelectUserServlet extends HttpServlet {


    private IUserService userService = new UserServiceImpl();


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf8");


        System.out.println("查询所有的用户:" + req);


        String username = req.getParameter("username");
        User user = userService.SelectUser(username);


        StringBuffer buffer = new StringBuffer();
        buffer.append("<html>");
        buffer.append("<body>");
        buffer.append("<table border=\"1\">");


        buffer.append("<tr>");
        buffer.append("<th>ID</th>");
        buffer.append("<th>用户名</th>");
        buffer.append("<th>密码</th>");
        buffer.append("<th>年龄</th>");
        buffer.append("<th>性别</th>");
        buffer.append("</tr>");


        if (user != null) {
            buffer.append("<tr>");
            buffer.append("<td>" + user.getId() + "</td>");
            buffer.append("<td>" + user.getUsername() + "</td>");
            buffer.append("<td>" + user.getPassword() + "</td>");
            buffer.append("<td>" + user.getAge() + "</td>");
            buffer.append("<td>" + user.getSex() + "</td>");
            buffer.append("</tr>");


        }
        buffer.append("</table>");
        buffer.append("</body>");
        buffer.append("</html>");
        buffer.append("<a href=\"GetUserListServlet\">查询所有用户</a>");
        resp.getWriter().write(buffer.toString());
    }
}




public class UpdateUserServlet extends HttpServlet {


    private IUserService userService = new UserServiceImpl();


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf8");


        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String age = req.getParameter("age");
        String sex = req.getParameter("sex");


        User user = new User();
        user.setUsername(username);
        user.setPassword(password);
        user.setAge(Integer.valueOf(age));
        user.setSex(Integer.valueOf(sex));
        int i = userService.UpdateUser(user);
        if (i == 0) {
            resp.getWriter().write("更新失败");
        } else {
            resp.getWriter().write("更新成功");
            resp.getWriter().write("<br><a href=\"GetUserListServlet\">查询所有用户</a>");
        }
    }
}




public class ViewUserServlet extends HttpServlet {


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {


        System.out.println("展示所有的用户:" + req);


        resp.setContentType("text/html;charset=utf8");
        System.out.println("username:" + req.getParameter("username"));


        List<User> userList = (List<User>) req.getAttribute("userList");


        StringBuffer buffer = new StringBuffer();
        buffer.append("<html>");
        buffer.append("<body>");
        buffer.append("<table border=\"1\">");


        buffer.append("<tr>");
        buffer.append("<th>ID</th>");
        buffer.append("<th>用户名</th>");
        buffer.append("<th>密码</th>");
        buffer.append("<th>年龄</th>");
        buffer.append("<th>性别</th>");
        buffer.append("</tr>");


        if (userList != null) {
            for (User user: userList) {
                buffer.append("<tr>");
                buffer.append("<td>" + user.getId() + "</td>");
                buffer.append("<td>" + user.getUsername() + "</td>");
                buffer.append("<td>" + user.getPassword() + "</td>");
                buffer.append("<td>" + user.getAge() + "</td>");
                buffer.append("<td>" + user.getSex() + "</td>");
                buffer.append("</tr>");
            }
        }


        buffer.append("</table>");
        buffer.append("</body>");
        buffer.append("</html>");


        resp.getWriter().write(buffer.toString());
    }
}

public interface IUserDao {


    public User login(String username);


    public List<User> getUserList();


    public int AddUser(User user);


    public int DeleteUser(String name);


    public int UpdateUser(User user);


    public User SelectUser(String name);
}




public class UserDaoImpl implements IUserDao {




    @Override
    public User login(String username) {


        String sql = "select * from t_user where username = ?";


        List<User> users = DaoUtils.commonQuery(sql, User.class, username);


        if (users.isEmpty()) {
            return null;
        }
        return users.get(0);
    }


    @Override
    public List<User> getUserList() {
        return DaoUtils.commonQuery("select * from t_user", User.class);
    }


    @Override
    public int AddUser(User user) {


        List<User> userList = getUserList();


        // 存在同名
        for (User subUser: userList) {
            if (subUser.getUsername().equals(user.getUsername())) {
                return 0;
            }
        }


        String sql = "insert into t_user(username, password, age, sex) value(?, ?, ?, ?)";
        int i = DaoUtils.commonUpdate(sql, user.getUsername(),user.getPassword(), user.getAge(),user.getSex());
        return i;
    }


    @Override
    public int DeleteUser(String username) {
        String sql = "delete  from t_user where username = ?";
        int i = DaoUtils.commonUpdate(sql, username);
        return i;
    }


    @Override
    public int UpdateUser(User user) {
        String sql = "update t_user set password=?,age=?,sex=? where username = ?";
        int i = DaoUtils.commonUpdate(sql,user.getPassword(),user.getAge(),user.getSex(),user.getUsername());
        return i;
    }


    public User SelectUser(String name) {


        List<User> users = DaoUtils.commonQuery("select * from t_user where username = ?", User.class, name);
        if (users.isEmpty()) {
            return null;
        }
        return users.get(0);
    }


}

@Data
public class User {


    private Integer id;
    private String username;
    private String password;
    private Integer age;
    private Integer sex;


}

public interface IUserService {


    public User login(String username, String password);


    public List<User> getUserList();


    public int AddUser(User user);


    public int DeleteUser(String name);


    public int UpdateUser(User user);


    public User SelectUser(String name);
}




public class UserServiceImpl implements IUserService {


    private IUserDao userDao = new UserDaoImpl();




    @Override
    public User login(String username, String password) {


        User user = userDao.login(username);


        if (user == null) {
            System.out.println("用户名或密码错误");
            return null;
        }


        if (!user.getPassword().equals(password)) {
            System.out.println("用户名或密码错误");
            return null;
        }


        return user;
    }


    @Override
    public List<User> getUserList() {
        return userDao.getUserList();
    }


    public int AddUser(User user) {
        return userDao.AddUser(user);
    }


    public int DeleteUser(String name) {
        return userDao.DeleteUser(name);
    }


    public int UpdateUser(User user) {
        return userDao.UpdateUser(user);
    }


    public User SelectUser(String name) {
        return userDao.SelectUser(name);
    }
}

public class DaoUtils {


    // 更改
    public static int commonUpdate(String sql, Object ...args) {


        Connection connection = DBUtils.getConnection();


        PreparedStatement prst = null;


        try {
            prst = connection.prepareStatement(sql);


            if (args != null && args.length > 0) {
                for (int i = 0; i < args.length; i ++) {
                    prst.setObject(i + 1,args[i]);
                }
            }
            return prst.executeUpdate();


        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtils.close(prst);
        }


        return 0;
    }


    // 查询
    public static <T> List<T> commonQuery(String sql, Class<T> cls, Object ...args) {
        Connection connection = DBUtils.getConnection();


        PreparedStatement prst = null;


        ResultSet resultSet = null;


        List<T> list = new ArrayList<>();


        try {
            prst = connection.prepareStatement(sql);
            if (args != null && args.length > 0) {
                for (int i = 0; i < args.length; i ++) {
                    prst.setObject(i + 1,args[i]);
                }
            }


            resultSet = prst.executeQuery();


            while (resultSet.next()) {
                T t = cls.newInstance();
                Field[] fields = cls.getDeclaredFields();
                for (Field field: fields) {
                    // 设置动态给属性赋值权限
                    field.setAccessible(true);
                    Object value = null;
                    try {
                        value = resultSet.getObject(field.getName());
                    } catch (SQLException e) {
                        // 出现实体字段和数据库字段不一致
                        String columnName = DBUtils.getProperties().getProperty(field.getName());
                        value = resultSet.getObject(columnName);
                    }
                    field.set(t, value);
                }
                list.add(t);


            }




        } catch (SQLException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } finally {
            DBUtils.close(resultSet, prst);
        }
        return list;
    }


}

public class DBUtils {


    private static DataSource dataSource = null;
    private static Properties properties = new Properties();
    private static ThreadLocal<Connection> threadLocal = new ThreadLocal<>();


    static {
        try {
            properties.load(DBUtils.class.getClassLoader().getResourceAsStream("jdbc.properties"));
            dataSource = DruidDataSourceFactory.createDataSource(properties);


        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }


    }


    public static Properties getProperties() {
        return properties;
    }


    public static Connection getConnection() {
        Connection connection = threadLocal.get();
        if (connection == null) {
            try {
                connection = dataSource.getConnection();
                threadLocal.set(connection);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return connection;
    }


    public static void close(AutoCloseable ...args) {
        for (AutoCloseable obj: args) {
            if (obj != null) {
                try {
                    obj.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

# jdbc.properties
#连接设置
driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/mydb1?characterEncoding=utf-8
username=root
password=Liu01234
#初始化可连接数量，实际项目时要设置更大值
initialSize=100
#最大连接数量
maxActive=500
#最小空闲连接，当空闲连接小于此值时会开辟新当空间，直到最大连接数量
minIdle=50
#超时等待时间以毫秒为单位 1000等于1秒
maxWait=5000

<!--  web.xml  -->
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
      http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
           version="2.5">


    <!--  登陆  -->
    <servlet>
        <servlet-name>LoginUserServlet</servlet-name>
        <servlet-class>com.baidu.day.test1.controller.LoginUserServlet</servlet-class>
    </servlet>


    <servlet-mapping>
        <servlet-name>LoginUserServlet</servlet-name>
        <url-pattern>/LoginUserServlet</url-pattern>
    </servlet-mapping>


    <!--  查所有  -->
    <servlet>
        <servlet-name>GetUserListServlet</servlet-name>
        <servlet-class>com.baidu.day.test1.controller.GetUserListServlet</servlet-class>
    </servlet>




    <servlet-mapping>
        <servlet-name>GetUserListServlet</servlet-name>
        <url-pattern>/GetUserListServlet</url-pattern>
    </servlet-mapping>


    <!--  重定向/转发跳转  -->
    <servlet>
        <servlet-name>ViewUserServlet</servlet-name>
        <servlet-class>com.baidu.day.test1.controller.ViewUserServlet</servlet-class>
    </servlet>


    <servlet-mapping>
        <servlet-name>ViewUserServlet</servlet-name>
        <url-pattern>/ViewUserServlet</url-pattern>
    </servlet-mapping>


    <!--  添加  -->
    <servlet>
        <servlet-name>AddUserServlet</servlet-name>
        <servlet-class>com.baidu.day.test1.controller.AddUserServlet</servlet-class>
    </servlet>


    <servlet-mapping>
        <servlet-name>AddUserServlet</servlet-name>
        <url-pattern>/AddUserServlet</url-pattern>
    </servlet-mapping>


    <!--  删  -->
    <servlet>
        <servlet-name>DeleteUserServlet</servlet-name>
        <servlet-class>com.baidu.day.test1.controller.DeleteUserServlet</servlet-class>
    </servlet>


    <servlet-mapping>
        <servlet-name>DeleteUserServlet</servlet-name>
        <url-pattern>/DeleteUserServlet</url-pattern>
    </servlet-mapping>


    <!--  改  -->
    <servlet>
        <servlet-name>UpdateUserServlet</servlet-name>
        <servlet-class>com.baidu.day.test1.controller.UpdateUserServlet</servlet-class>
    </servlet>


    <servlet-mapping>
        <servlet-name>UpdateUserServlet</servlet-name>
        <url-pattern>/UpdateUserServlet</url-pattern>
    </servlet-mapping>


<!--  查  -->
    <servlet>
        <servlet-name>SelectUserServlet</servlet-name>
        <servlet-class>com.baidu.day.test1.controller.SelectUserServlet</servlet-class>
    </servlet>


    <servlet-mapping>
        <servlet-name>SelectUserServlet</servlet-name>
        <url-pattern>/SelectUserServlet</url-pattern>
    </servlet-mapping>


</web-app>

<%-- index.jsp --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>


  <form method="post" action="LoginUserServlet">
    username:<input type="text" name="username" value="zs"><br><br>
    password:<input type="text" name="password" value="123"><br><br>


    <input type="submit" value="登陆">
  </form>
  <br><br>


  <form method="post" action="AddUserServlet">
    username:<input type="text" name="username" value="zs"><br><br>
    password:<input type="text" name="password" value="123"><br><br>
    age:<input type="text" name="age" value="12"><br><br>
    sex:<input type="text" name="sex" value="1"><br><br>


    <input type="submit" value="添加用户">
  </form>
  <br><br>


  <form method="post" action="DeleteUserServlet">
    username:<input type="text" name="username" value="zs"><br><br>


    <input type="submit" value="删除用户">
  </form>
  <br><br>


  <form method="post" action="SelectUserServlet">
    username:<input type="text" name="username" value="zs"><br><br>


    <input type="submit" value="查询用户">
  </form>
  <br><br>


  <form method="post" action="UpdateUserServlet">
    username:<input type="text" name="username" value="zs"><br><br>
    password:<input type="text" name="password" value="123"><br><br>
    age:<input type="text" name="age" value="12"><br><br>
    sex:<input type="text" name="sex" value="1"><br><br>


    <input type="submit" value="修改用户">
  </form>
  <br><br>


  </body>
</html>

数据库

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servlet2 单元测试、转发、重定向

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