添加依赖项后出现 Spring Data REST 问题

Question

我正在尝试使用 spring Data REST 配置我的 springboot 应用程序。我在使用 Spring-Data REST 显示来自我的实体类的数据时遇到了挑战。我已将必要的依赖项添加到我的 pom.xml 文件中，但是当我尝试在 Web 浏览器上或通过邮递员访问端点时，我什么也得不到。

查看来自网络浏览器和邮递员的错误消息：

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Mar 24 18:41:33 PDT 2020
There was an unexpected error (type=Not Found, status=404).
No message available

Postman error message


{
{
  "timestamp" : "2020-03-25T01:13:38.867+0000",
  "timestamp" : "2020-
  "status" : 404,
  "error" : "Not Found",
  "message" : "No message available",
  "path" : "/api/employees"
}

这里是 pom.xml 文件

<?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>2.1.13.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.dafe.spring</groupId>
    <artifactId>AppLogger</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>AppLogger</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-data-jpa</artifactId>
        </dependency>

        <!-- Add dependency for Spring Data REST -->
<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>
        </dependency>
    </dependencies>

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

</project>

这是我名为 Employee 的实体类

package com.dafe.spring.logger.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="employee")
public class Employee {

    // define fields

    @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;


    // define constructors

    public Employee() {

    }

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

    // define getter/setter

    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;
    }

    // define tostring

    @Override
    public String toString() {
        return "Employee [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", email=" + email + "]";
    }

}

这是我的 EmployeeRepository 接口

package com.dafe.spring.logger.dao;

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

import com.dafe.spring.logger.entity.Employee;

public interface EmployeeRepository extends JpaRepository<Employee, Integer> {

}

如果有任何帮助，我将不胜感激。谢谢

Answer 1

编辑：此答案不适用于 Spring Data REST 用户，因为它显然会自动配置映射。

我在您发布的代码中没有看到 /api/employees 的映射。

您是否定义了带有@GetMapping("/api/employees") 注释的方法？ 它应该在一个用@RestController注解的类中。

@GetMapping("/api/employees")
public List<Employee> getEmployees() {
    // Get employees from EmployeeRepository
}

Answer 2

我通过更改 application.properties 文件中的基本 uri 解决了这个问题，我添加了 spring.data.rest.basePath=/api，它就像魔术一样工作

根据 Spring Data Rest 的文档，“默认情况下，Spring Data REST 在根 URI '/' 处提供 REST 资源。有多种方法可以更改基本路径。

使用 Spring Boot 1.2 及更高版本，您可以通过在 application.properties 中设置单个属性来更改基本 URI，如下所示：spring.data.rest.basePath=/api"

有关 Spring Data REST 的更多详细信息，请使用此链接：Spring Data REST reference guide