Java 框架实操内容：从入门到精通的 Spring Boot 3.x 与 MyBatis-Plus 实战教程

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啦啦啦191

修改于 2025-07-24 11:10:35

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文章被收录于专栏：Java开发Java开发

以下是补充了Java最新技术和框架实操内容的完整文章：

Java学习资料汇总（含最新技术实操）

一、Java基础环境搭建（Java 17+）

1. JDK 17 安装与配置

推荐使用 SDKMAN! 管理Java版本：

# 安装SDKMAN!
curl -s "https://get.sdkman.io" | bash
source "$HOME/.sdkman/bin/sdkman-init.sh"

# 安装Java 17 LTS
sdk install java 17.0.8-tem
sdk default java 17.0.8-tem

2. 现代化IDE配置（IntelliJ IDEA）

启用Preview Features：Settings > Build, Execution, Deployment > Compiler > Java Compiler > Additional command line parameters: --enable-preview
配置Lombok插件：Settings > Plugins > Marketplace > 搜索"Lombok"并安装

二、Java新特性实战

1. 模式匹配（Java 17+）

// 旧写法
if (obj instanceof String) {
    String s = (String) obj;
    System.out.println(s.length());
}

// 新模式匹配
if (obj instanceof String s) {
    System.out.println(s.length());
}

// 结合switch表达式
Object obj = LocalDate.now();
int hashCode = switch (obj) {
    case String s -> s.hashCode();
    case Integer i -> i.hashCode();
    case LocalDate d -> d.getDayOfMonth();
    default -> obj.toString().hashCode();
};

2. 文本块（Java 15+）

// 旧写法
String html = "<html>\n" +
              "    <body>\n" +
              "        <p>Hello, World!</p>\n" +
              "    </body>\n" +
              "</html>";

// 文本块写法
String html = """
              <html>
                  <body>
                      <p>Hello, World!</p>
                  </body>
              </html>
              """;

3. 记录类（Java 16+）

// 传统JavaBean
public class Person {
    private final String name;
    private final int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    // getters, equals, hashCode, toString
}

// 记录类写法
record Person(String name, int age) {}

三、Spring Boot 3 与微服务实战

1. 创建RESTful API项目

使用Spring Initializr快速创建项目：

curl https://start.spring.io/starter.tgz -d dependencies=web,data-jpa,validation,actuator -d javaVersion=17 -d type=maven-project -d groupId=com.example -d artifactId=demo -d name=demo | tar -xzvf -

2. 控制器与验证

@RestController
@RequestMapping("/api/users")
public class UserController {

    @Autowired
    private UserService userService;

    @PostMapping
    public ResponseEntity<User> createUser(@Valid @RequestBody UserRequest request) {
        User user = userService.createUser(request);
        return ResponseEntity.created(URI.create("/api/users/" + user.getId())).body(user);
    }

    @GetMapping("/{id}")
    public ResponseEntity<User> getUser(@PathVariable Long id) {
        return userService.getUserById(id)
                .map(ResponseEntity::ok)
                .orElse(ResponseEntity.notFound().build());
    }
}

// 验证注解示例
public record UserRequest(
    @NotBlank(message = "姓名不能为空")
    String name,
    
    @Email(message = "邮箱格式不正确")
    String email,
    
    @Min(value = 18, message = "必须年满18岁")
    Integer age
) {}

3. 配置文件分层管理

# application.yml
spring:
  application:
    name: user-service
  profiles:
    active: dev

# application-dev.yml
spring:
  datasource:
    url: jdbc:postgresql://localhost:5432/user_db
    username: postgres
    password: password
  jpa:
    hibernate:
      ddl-auto: update
    properties:
      hibernate:
        dialect: org.hibernate.dialect.PostgreSQLDialect

# application-prod.yml
spring:
  datasource:
    url: jdbc:postgresql://prod-db:5432/user_db
    username: ${DB_USERNAME}
    password: ${DB_PASSWORD}

四、响应式编程（Spring WebFlux）

1. 创建响应式API

@RestController
@RequestMapping("/api/books")
public class BookController {

    @Autowired
    private BookRepository bookRepository;

    @GetMapping
    public Flux<Book> getAllBooks() {
        return bookRepository.findAll();
    }

    @PostMapping
    public Mono<Book> createBook(@RequestBody Book book) {
        return bookRepository.save(book);
    }
}

// 响应式Repository
public interface BookRepository extends ReactiveCrudRepository<Book, String> {
    Flux<Book> findByAuthor(String author);
}

2. 响应式测试

@WebFluxTest(BookController.class)
class BookControllerTest {

    @Autowired
    private WebTestClient webTestClient;

    @MockBean
    private BookRepository bookRepository;

    @Test
    void shouldReturnAllBooks() {
        Book book = new Book("1", "Java 17", "Doubao");
        when(bookRepository.findAll()).thenReturn(Flux.just(book));

        webTestClient.get().uri("/api/books")
                .exchange()
                .expectStatus().isOk()
                .expectBodyList(Book.class)
                .contains(book);
    }
}

五、容器化与云原生部署

1. Dockerfile配置

# 基础镜像
FROM eclipse-temurin:17-jdk-alpine

# 设置工作目录
WORKDIR /app

# 复制依赖文件
COPY mvnw .
COPY .mvn .mvn
COPY pom.xml .

# 下载依赖
RUN ./mvnw dependency:go-offline -B

# 复制源代码
COPY src src

# 构建应用
RUN ./mvnw package -DskipTests
RUN mkdir -p target/dependency && (cd target/dependency; jar -xf ../*.jar)

# 创建运行时镜像
FROM eclipse-temurin:17-jre-alpine
VOLUME /tmp
ARG DEPENDENCY=/app/target/dependency
COPY --from=0 ${DEPENDENCY}/BOOT-INF/lib /app/lib
COPY --from=0 ${DEPENDENCY}/META-INF /app/META-INF
COPY --from=0 ${DEPENDENCY}/BOOT-INF/classes /app

# 暴露端口
EXPOSE 8080

# 启动应用
ENTRYPOINT ["java","-cp","app:app/lib/*","com.example.demo.DemoApplication"]

2. Kubernetes部署清单

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service
  labels:
    app: user-service
spec:
  replicas: 3
  selector:
    matchLabels:
      app: user-service
  template:
    metadata:
      labels:
        app: user-service
    spec:
      containers:
      - name: user-service
        image: doubao/user-service:1.0.0
        ports:
        - containerPort: 8080
        env:
        - name: SPRING_PROFILES_ACTIVE
          value: prod
        - name: DB_USERNAME
          valueFrom:
            secretKeyRef:
              name: db-secret
              key: username
        - name: DB_PASSWORD
          valueFrom:
            secretKeyRef:
              name: db-secret
              key: password
        livenessProbe:
          httpGet:
            path: /actuator/health
            port: 8080
          initialDelaySeconds: 30
          periodSeconds: 10
        readinessProbe:
          httpGet:
            path: /actuator/health
            port: 8080
          initialDelaySeconds: 10
          periodSeconds: 5

六、测试与DevOps实践

1. 单元测试与集成测试

@SpringBootTest
@AutoConfigureMockMvc
class UserControllerIntegrationTest {

    @Autowired
    private MockMvc mockMvc;

    @Autowired
    private UserRepository userRepository;

    @Test
    void shouldCreateUser() throws Exception {
        UserRequest request = new UserRequest("Doubao", "doubao@example.com", 20);

        mockMvc.perform(post("/api/users")
                .contentType(MediaType.APPLICATION_JSON)
                .content(objectMapper.writeValueAsString(request)))
                .andExpect(status().isCreated())
                .andExpect(header().string("Location", containsString("/api/users/")));

        assertThat(userRepository.count()).isEqualTo(1);
    }
}

2. GitHub Actions CI/CD流程

name: Java CI with Maven

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v4
    - name: Set up JDK 17
      uses: actions/setup-java@v4
      with:
        java-version: '17'
        distribution: 'temurin'
        cache: maven

    - name: Build with Maven
      run: mvn -B package --file pom.xml

    - name: Run Tests
      run: mvn test

    - name: Build Docker Image
      if: github.ref == 'refs/heads/main'
      uses: docker/build-push-action@v5
      with:
        context: .
        push: false
        tags: doubao/user-service:${{ github.sha }}

    - name: Upload Artifact
      uses: actions/upload-artifact@v4
      with:
        name: target
        path: target/*.jar

通过以上实操内容，你可以系统性地学习Java最新技术栈，从语言特性到微服务架构，再到云原生部署，形成完整的知识体系。建议按照从基础到高级的顺序逐步实践，并结合官方文档深入理解每个技术点的原理和最佳实践。

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