1
<packaging>war</packaging>

1
your-app.war
2
 └── WEB-INF/
3
      ├── web.xml
4
      ├── classes/   （编译后的字节码）
5
      └── lib/       （依赖的jar包）

1
打 WAR 包 →
2

3
写 web.xml 注册 Servlet/Filter →
4

5
放到容器的 webapps →
6

7
启动容器访问应用。

1
import jakarta.servlet.annotation.WebServlet;
2
import jakarta.servlet.http.*;
3

4
@WebServlet("/hello")
5
public class HelloServlet extends HttpServlet {
6
    @Override
7
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
8
        resp.getWriter().println("Hello World!");
9
    }
10
}

1
客户端发起请求 →
2
容器（Tomcat）检查 URL 映射到哪些 Filter →
3
依次执行这些 Filter 的 doFilter() →
4
执行目标 Servlet/JSP →
5
响应返回时，再倒序经过这些 Filter →
6
返回给客户端。

1
<filter>
2
    <filter-name>EncodingFilter</filter-name>
3
    <filter-class>com.example.filter.EncodingFilter</filter-class>
4
    <init-param>
5
        <param-name>encoding</param-name>
6
        <param-value>UTF-8</param-value>
7
    </init-param>
8
</filter>
9
<filter-mapping>
10
    <filter-name>EncodingFilter</filter-name>
11
    <url-pattern>/*</url-pattern>
12
</filter-mapping>

1
<filter>
2
    <filter-name>AuthFilter</filter-name>
3
    <filter-class>com.example.filter.AuthFilter</filter-class>
4
</filter>
5
<filter-mapping>
6
    <filter-name>AuthFilter</filter-name>
7
    <url-pattern>/secure/*</url-pattern>
8
</filter-mapping>

1
请求 → DispatcherServlet → Controller → Service → Mapper → DB → 返回

1
package com.bx33661.springlearn.controller;
2

3
import com.bx33661.springlearn.entity.User;
4
import org.springframework.web.bind.annotation.PostMapping;
5
import org.springframework.web.bind.annotation.RestController;
6

7
@RestController
8
public class LoginController {
9
    @PostMapping("/login")
10
    public String login(User user) {
11
        System.out.println("name: " + user.getName());
12
        System.out.println("password: " + user.getPassword());
13
        return "success";
14
    }
15
}

1
package com.bx33661.springlearn.entity;
2

3
public class User {
4
    private String name;
5
    private String password;
6

7
    public String getName() {
8
        return name;
9
    }
10

11
    public void setName(String name) {
12
        this.name = name;
13
    }
14

15
    public String getPassword() {
16
        return password;
17
    }
18

19
    public void setPassword(String password) {
20
        this.password = password;
21
    }
22
}

1
import java.io.Serializable;
2

3
public class Student implements Serializable {
4
    // 为了避免不同编译器生成不同的序列化ID
5
    private static final long serialVersionUID = 1L;
6

7
    private String id;
8
    private String name;
9

10
    // 必须有无参构造函数
11
    public Student() {}
12

13
    // 有参构造也可以，方便初始化
14
    public Student(String id, String name) {
15
        this.id = id;
16
        this.name = name;
17
    }
18

19
    // Getter / Setter
20
    public String getId() {
21
        return id;
22
    }
23

24
    public void setId(String id) {
25
        this.id = id;
26
    }
27

28
    public String getName() {
29
        return name;
30
    }
31

32
    public void setName(String name) {
33
        this.name = name;
34
    }
35

36
    // 重写toString，方便打印对象
37
    @Override
38
    public String toString() {
39
        return "Student{id='" + id + "', name='" + name + "'}";
40
    }
41
}

1
{
2
  "timestamp": "2025-09-29T13:22:33.134+00:00",
3
  "status": 404,
4
  "error": "Not Found",
5
  "message": "No message available",
6
  "path": "/test"
7
}

1
src/main/resources/
2
    └── templates/error/      # 或者 static/error/
3
        ├── 404.html
4
        ├── 500.html
5
        └── error.html

1
@Controller
2
public class MyErrorController implements ErrorController {
3

4
    @RequestMapping("/error")
5
    @ResponseBody
6
    public Map<String, Object> handleError(HttpServletRequest request) {
7
        Object status = request.getAttribute(RequestDispatcher.ERROR_STATUS_CODE);
8
        Map<String, Object> map = new HashMap<>();
9
        map.put("code", status);
10
        map.put("msg", "出错啦，请联系管理员~");
11
        return map;
12
    }
13

14
    public String getErrorPath() {
15
        return "/error";
16
    }
17
}

1
package org.example.start;
2

3
import org.springframework.boot.SpringApplication;
4
import org.springframework.boot.autoconfigure.SpringBootApplication;
5

6
@SpringBootApplication
7
public class StartApplication {
8

9
    public static void main(String[] args) {
10
        SpringApplication.run(StartApplication.class, args);
11
    }
12
}

1
spring:
2
  datasource:
3
    url: jdbc:mysql://localhost:3306/test
4
    username: root
5
    password: 123456

1
<dependency>
2
    <groupId>org.springframework.boot</groupId>
3
    <artifactId>spring-boot-devtools</artifactId>
4
    <optional>true</optional> <!-- 防止被下游依赖到生产包 -->
5
</dependency>

1
<build>
2
  <plugins>
3
    <plugin>
4
      <groupId>org.springframework.boot</groupId>
5
      <artifactId>spring-boot-maven-plugin</artifactId>
6
      <configuration>
7
        <addResources>true</addResources>
8
      </configuration>
9
    </plugin>
10
  </plugins>
11
</build>

1
key=value

1
server.port=8080

1
greeting=Hello\nWorld
2
chinese=\u4F60\u597D