Question

我收到以下错误。即使我在POJO中有正确的get set方法。

java.lang.IllegalArgumentException：找不到类型返回值的转换器：class com.example.demo.entities.Department 在org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters（AbstractMessageConverterMethodProcessor.java:187）〜[spring-webmvc-4.3.12.RELEASE.jar：4.3.12.RELEASE]

的pom.xml

   <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>1.5.8.RELEASE</version>
    </dependency>

POJO：

package com.example.demo.entities;

import javax.persistence.*;

@Entity
@Table(name="departments")
public class Department  {

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name="DEPT_NO")
private Long id;

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

public Department() {
}

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;
}



}

的Controler

@GetMapping("/departments/{id}")
public ResponseEntity<Department> getDepartmentById(@PathVariable(value = "id") Long departmentId) {
    Department department = departmentRepository.findOne(departmentId);
    if(department == null) {
        return ResponseEntity.notFound().build();
    } else {
        System.out.println("name is" + department.getName());
    }
    return ResponseEntity.ok().body(department);
}

不确定，这是因为我有正确的设置方法。

请帮忙。

Answer 1

您需要将Jackson依赖项添加到您的pom.xml

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.5.0</version>
</dependency>

如果您未对控制器使用@RestController注释，则需要在@ResponseBody方法中添加@GetMapping注释。

@ResponseBody
@GetMapping("/departments/{id}")

虽然有适当的get set方法，但没有为类型的返回值找到转换器

1 个答案: