SpringMVC使用注解实现登录功能

下面我将为您详细讲解如何使用注解实现SpringMVC的登录功能。

1. 创建SpringMVC项目

首先，我们需要使用Maven工具创建一个空的SpringMVC项目：

<groupId>com.example</groupId>
<artifactId>springmvcdemo</artifactId>
<version>0.0.1-SNAPSHOT</version>

2. 创建实体类

接着，我们需要创建一个实体类，用于储存用户信息。这里我们创建一个User类：

public class User {
    private String username;
    private String password;

    // getters and setters
}

3. 创建DAO层

然后，我们需要创建一个DAO层，用于查询数据库中的用户信息。这里我们使用JdbcTemplate进行数据库操作：

@Repository
public class UserDao {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public User getUser(String username) {
        List<User> userList = jdbcTemplate.query(
            "SELECT * FROM user WHERE username = ?",
            new Object[]{username},
            new BeanPropertyRowMapper<>(User.class)
        );

        return userList.isEmpty() ? null : userList.get(0);
    }
}

4. 创建Service层

接下来，我们需要创建一个Service层，对DAO层进行包装，提供更加友好的API：

@Service
public class UserService {
    @Autowired
    private UserDao userDao;

    public boolean verifyUser(String username, String password) {
        User user = userDao.getUser(username);
        return user != null && user.getPassword().equals(password);
    }
}

5. 创建Controller

现在我们需要创建Controller层，处理用户请求。这里我们使用注解，实现登录功能。

@Controller
public class LoginController {
    @Autowired
    private UserService userService;

    @RequestMapping("/login")
    public String login() {
        return "login";
    }

    @PostMapping("/doLogin")
    public String doLogin(@RequestParam("username") String username,
                          @RequestParam("password") String password,
                          HttpSession session,
                          Model model) {
        if (userService.verifyUser(username, password)) {
            session.setAttribute("username", username);
            return "redirect:/home";
        } else {
            model.addAttribute("msg", "Invalid username or password.");
            return "login";
        }
    }

    @RequestMapping("/home")
    public String home(HttpSession session, Model model) {
        String username = (String) session.getAttribute("username");
        if (username != null) {
            model.addAttribute("username", username);
            return "home";
        } else {
            return "redirect:/login";
        }
    }
}

6. 创建页面

最后，我们需要创建登录页面和主页页面。

login.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Login</title>
</head>
<body>
    <h1>Login</h1>
    <p style="color: red;">${msg}</p>
    <form action="/doLogin" method="post">
        <p>
            <label for="username">Username:</label>
            <input type="text" id="username" name="username">
        </p>
        <p>
            <label for="password">Password:</label>
            <input type="password" id="password" name="password">
        </p>
        <p>
            <input type="submit" value="Login">
        </p>
    </form>
</body>
</html>

home.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Home</title>
</head>
<body>
    <h1>Home</h1>
    <p>Welcome, ${username}!</p>
</body>
</html>

好了，现在您已经学会如何使用注解实现SpringMVC的登录功能。如果您还有疑问，可以参考下面的示例。

示例一

@RunWith(SpringRunner.class)
@SpringBootTest
@WebAppConfiguration
public class LoginControllerTest {
    private MockMvc mockMvc;

    @Autowired
    private WebApplicationContext webApplicationContext;

    @Before
    public void setUp() {
        mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
    }

    @Test
    public void testLogin() throws Exception {
        mockMvc.perform(
            MockMvcRequestBuilders.get("/login")
        ).andExpect(
            MockMvcResultMatchers.status().isOk()
        ).andExpect(
            MockMvcResultMatchers.view().name("login")
        );
    }

    @Test
    public void testDoLogin_success() throws Exception {
        mockMvc.perform(
            MockMvcRequestBuilders.post("/doLogin")
                .param("username", "admin")
                .param("password", "123456")
        ).andExpect(
            MockMvcResultMatchers.status().is3xxRedirection()
        ).andExpect(
            MockMvcResultMatchers.view().name("redirect:/home")
        ).andExpect(
            MockMvcResultMatchers.redirectedUrl("/home")
        );
    }

    @Test
    public void testDoLogin_failure() throws Exception {
        mockMvc.perform(
            MockMvcRequestBuilders.post("/doLogin")
                .param("username", "admin")
                .param("password", "654321")
        ).andExpect(
            MockMvcResultMatchers.status().isOk()
        ).andExpect(
            MockMvcResultMatchers.view().name("login")
        ).andExpect(
            MockMvcResultMatchers.model().attributeExists("msg")
        );
    }

    @Test
    public void testHome() throws Exception {
        mockMvc.perform(
            MockMvcRequestBuilders.get("/home")
        ).andExpect(
            MockMvcResultMatchers.status().is3xxRedirection()
        ).andExpect(
            MockMvcResultMatchers.redirectedUrl("/login")
        );
    }
}

示例二

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @PostMapping("/login")
    public Map<String, Object> login(@RequestParam("username") String username,
                                     @RequestParam("password") String password,
                                     HttpSession session) {
        Map<String, Object> resultMap = new HashMap<>();
        if (userService.verifyUser(username, password)) {
            session.setAttribute("username", username);
            resultMap.put("code", 0);
            resultMap.put("msg", "Login success.");
        } else {
            resultMap.put("code", 1);
            resultMap.put("msg", "Invalid username or password.");
        }

        return resultMap;
    }

    @GetMapping("/home")
    public Map<String, Object> home(HttpSession session) {
        Map<String, Object> resultMap = new HashMap<>();
        String username = (String) session.getAttribute("username");
        if (username != null) {
            resultMap.put("code", 0);
            resultMap.put("msg", "Welcome, " + username + "!");
        } else {
            resultMap.put("code", 1);
            resultMap.put("msg", "Please login first.");
        }

        return resultMap;
    }
}

希望这些内容能够帮助到您。

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