Spring Data REST 端点提供 404 状态码

Question

我正在尝试开发一个简单的 Spring Boot Customer CRUD 应用程序。我正在使用 Spring REST Data 和 JPA。 CRUD 的端点应该是自动生成的，但是当我尝试访问它们时，它给出了 404 未找到。

这里是 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>2.2.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.rest.data</groupId>
    <artifactId>demo-application</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo-application</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-rest</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

客户实体：

package com.rest.data.entity;

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

@Entity
@Table(name = "customers")
public class Customer {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private int id;

    @Column(name = "first_name")
    private String firstName;

    @Column(name = "last_name")
    private String lastName;

    @Column(name = "email")
    private String email;

    public Customer() {

    }

    public Customer(String firstName, String lastName, String email) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    public Customer(int id, String firstName, String lastName, String email) {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}

客户存储库：

package com.rest.data.repository;

import com.rest.data.entity.Customer;
import org.springframework.data.jpa.repository.JpaRepository;


public interface CustomerRepository extends JpaRepository<Customer, Integer> {

}

和application.properities：

#
##Database properties
#
spring.datasource.url=jdbc:mysql://localhost:3306/customer_crm
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

#
##JPA properties 
#
spring.jpa.show-sql = true
spring.jpa.hibernate.ddl-auto = update
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

#
##Application actuator info data
#
info.app.name=demo-application
info.app.version=1.0.0
info.app.authoer=Mafit Atyo

#
##Expose all endpoints for the actuator
#
management.endpoints.web.exposure.include=*


#
##Application context path
#
server.servlet.context-path=/demo-application

我正在尝试访问 http://localhost:8080/demo-application/customers 以将所有客户列为 JSON，但它返回一个状态为 404 的白标签页面。有什么建议吗？

Answer 1

从示例中试试这个 (https://spring.io/guides/gs/accessing-data-rest/)：

package com.example.accessingdatarest;

import java.util.List;

import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;

@RepositoryRestResource(collectionResourceRel = "people", path = "people")
public interface PersonRepository extends PagingAndSortingRepository<Person, Long> {

  List<Person> findByLastName(@Param("name") String name);

}

Answer 2

我发现了问题！ Spring Boot 应用程序无法扫描和检测存储库和实体，因为它们不是主包中的子包。

我在com.rest.data.entity 和com.rest.data.repository 中有Customer 实体和CustomerRepository，它们不是主包com.rest.data.demoapplication 的子包。因此，应用程序无法扫描和检测它们，但是当我将实体和存储库包的名称更改为图片时，它就起作用了！