我正在使用 Spring Boot 2 创建 Web 应用程序并使用 CommandLineRunner 运行该应用程序以连接 PostgreSql 数据库
1 . “链接库”接口:
package com.example.demo;
import org.springframework.data.repository.CrudRepository;
import com.example.entity.Link;
public interface LinkRepository extends CrudRepository<Link, Long> {
}
2.“链接”实体:
package com.example.entity;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "link")
public class Link {
@Id
@GeneratedValue
@Column(name = "id")
private Long id;
@Column(name = "NAME")
private String name;
@Column(name = "url", unique = true)
private String url;
public Link(String name, String url) {
this.name = name;
this.url = url;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
}
3. 演示应用配置:
package com.example.demo;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import com.example.entity.Link;
@SpringBootApplication(scanBasePackages = { "com.example" })
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
@Bean
public CommandLineRunner demo(LinkRepository repository) {
// TODO Auto-generated method stub
return (args) -> {
repository.save(new Link("test", "link"));
for (Link linkrepo : repository.findAll()) {
System.out.println(linkrepo.getName());
}
};
}
}
4. pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.7.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
5. Application.properties :
spring.datasource.url=jdbc:postgresql://localhost:5432/TestDb
spring.datasource.username=postgres
spring.datasource.password=root
spring.datasource.driver-class-name=org.postgresql.Driver
spring.jpa.hibernate.ddl-auto = create
spring.h2.console.enabled=true
spring.jpa.properties.hibernate.jdbc.lob.non_contextual_creation=true
spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults = false
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQL95Dialect
我收到以下错误:
org.springframework.beans.factory.UnsatisfiedDependencyException:在 com.example.demo.DemoApplication 中定义名称为“demo”的 bean 创建时出错:通过方法“demo”参数 0 表达的不满意依赖;嵌套异常是 org.springframework.beans.factory.BeanCreationException:创建名为“linkRepository”的 bean 时出错:init 方法调用失败;嵌套异常是 java.lang.IllegalArgumentException: Not a managed type: class com.example.entity.Link
添加@EntityScan("com.example.entity")
DemoApplication 类或将 DemoApplication 移动到 'com.example' 包,然后 spring 将扫描所有子包。
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