有一段代碼：package com.example.sweater3.domain;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;@Entitypublic class Message { @Id @GeneratedValue(strategy=GenerationType.AUTO) private Integer id; private String text; private String tag; public Message() { } public Message(String text, String tag) { this.text = text; this.tag = tag; } public void setText(String text) { this.text = text; } public String getText() { return text; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getTag() { return tag; } public void setTag(String tag) { this.tag = tag; }}_package com.example.sweater3.repos;import com.example.sweater3.domain.Message;import org.springframework.data.repository.CrudRepository;import org.springframework.stereotype.Repository;import java.util.List;@Repositorypublic interface MessageRepo extends CrudRepository<Message, Long> { List<Message> findByTag(String tag);}__package com.example.sweater3;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplicationpublic class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); }}__package com.example.sweater3;import com.example.sweater3.repos.MessageRepo;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;@Controllerpublic class GreetingController { @Autowired private MessageRepo messageRepo;}
1 回答
紅顏莎娜
TA貢獻(xiàn)1842條經(jīng)驗(yàn) 獲得超13個(gè)贊
您必須在應(yīng)用程序中啟用存儲(chǔ)庫：
@SpringBootApplication
@EnableJpaRepositories
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
另請(qǐng)確保添加：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
更新：您必須配置數(shù)據(jù)庫連接和驅(qū)動(dòng)程序。H2 示例（在內(nèi)存數(shù)據(jù)庫中）
添加新的依賴項(xiàng)：
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
在 application.properties 中添加：
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
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