Spring Boot注解 之 @EnableAutoConfiguration

本文的示例代码参考EnableAutoConfiguration

目录

• 开始

• @EnableAutoConfiguration

• 一个自动配置案例

  • 依赖

  • 模型

  • 持久化

  • 控制器

开始

spring init -dweb --build gradle EnableAutoConfiguration

# cd EnableAutoConfiguration
vim src/main/java/com/example/EnableAutoConfiguration/HelloController.java

package com.example.EnableAutoConfiguration;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @RequestMapping("/")
    public String hello() {
        return "HelloController";
    }
}

• 测试

./gradlew bootrun

curl localhost:8080 # 返回"HelloController"

更多参考 Spring Boot注解 之 @ComponentScan

@EnableAutoConfiguration

@SpringBootApplication = @Configuration + @EnableAutoConfiguration + @ComponentScan

vim src/main/java/com/example/EnableAutoConfiguration/DemoApplication.java

package com.example.EnableAutoConfiguration;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

• 测试

./gradlew bootrun

curl localhost:8080 # 返回"HelloController"

一个自动配置案例

依赖

./gradlew dependencies  | grep jpa && ./gradlew dependencies  | grep h2

vim build.gradle

# 省略了未修改代码
dependencies {
    compile('org.springframework.boot:spring-boot-starter-web')
    compile('org.springframework.boot:spring-boot-starter-data-jpa')
    compile('com.h2database:h2')
    testCompile('org.springframework.boot:spring-boot-starter-test')
}

./gradlew dependencies  | grep jpa && ./gradlew dependencies  | grep h2

模型

vim src/main/java/com/example/EnableAutoConfiguration/Book.java

package com.example.EnableAutoConfiguration;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Book {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;

    private String title;

    public Long getId() {
        return id;
    }
    
    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

持久化

vim src/main/java/com/example/EnableAutoConfiguration/ReadingListRepository.java

package com.example.EnableAutoConfiguration;

import java.util.List;

import org.springframework.data.jpa.repository.JpaRepository;

public interface ReadingListRepository extends JpaRepository {
    List findByTitle(String title);
}

控制器

vim src/main/java/com/example/EnableAutoConfiguration/HelloController.java

# 省略了未修改代码
public class ReadingListController {

    private ReadingListRepository readingListRepository;

    @Autowired
    public ReadingListController(ReadingListRepository readingListRepository) {
        this.readingListRepository = readingListRepository;
    }

    @GetMapping("/readinglist")
    public List readingListByTitle(@RequestParam(value="title") String title) {
        return readingListRepository.findByTitle(title);
    }
    
    @PostMapping("/readinglist")
    public Book addToReadingList(@RequestBody Book book) {
        System.out.println(book);
        return readingListRepository.save(book);
    }
}

• 测试

./gradlew bootrun

curl -X POST -H "Content-type: application/json" -d '{"title":"title1"}' http://localhost:8080/readinglist # {"id":1,"title":"title1"}

curl -X POST -H "Content-type: application/json" -d '{"title":"title2"}' http://localhost:8080/readinglist # {"id":2,"title":"title2"}

curl localhost:8080/readinglist?title=title1 # [{"id":1,"title":"title1"}]

curl localhost:8080/readinglist?title=title2 # [{"id":2,"title":"title2"}]

参考

• Spring Boot实战

• A Guide to Spring Framework Annotations