【发布时间】：2019-01-23 09:17:22
【问题描述】：
我为这个异常和原因找到了多种解决方案，但没有一个有效，而且看起来不合逻辑。
我有如下的 REST 服务类
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.http.MediaType;
import java.util.Map;
@RestController
public class UserRestService {
@RequestMapping(value = "/userLogin", method = RequestMethod.POST, produces = MediaType.APPLICATION_XML_VALUE, consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
public @ResponseBody ResponseEntity<Map> login(@RequestBody Map<String, String> name) {
ResponseEntity<Map> res = null;
name.values().forEach(System.out::println);
return new ResponseEntity<Map>(name, HttpStatus.OK);
}
}
如您所见，我尝试创建一个 POST 请求，请求正文为 JSON，响应为 XML，在此过程中打印请求。这只是一个简单的示例，但是当请求被正确打印时，这意味着它已被接收并编组到 Map。但是响应状态是 406（不可接受）
日志中的异常是
John
30
null
2018-08-16 14:05:48.440 WARN 22820 --- [nio-8080-exec-2] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved exception caused by Handler execution: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
2018-08-16 14:05:48.481 WARN 22820 --- [nio-8080-exec-2] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved exception caused by Handler execution: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
请求头只有
Accept:*/*
Content-Type:application/json
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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example.cms</groupId>
<artifactId>business</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<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-web</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.6</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>javax.xml.bind</groupId>
<artifactId>jaxb-api</artifactId>
<version>2.3.0</version>
</dependency>
<dependency>
<groupId>com.sun.xml.bind</groupId>
<artifactId>jaxb-core</artifactId>
<version>2.3.0.1</version>
</dependency>
<dependency>
<groupId>com.sun.xml.bind</groupId>
<artifactId>jaxb-impl</artifactId>
<version>2.3.0.1</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
注意添加以下依赖可以解决问题
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
</dependency>
请求正文{ "name":"John", "age":30, "car":null }
如果MediaType.APPLICATION_JSON_UTF8_VALUE 用于produces 的@RequestMapping 属性为{ "name":"John", "age":30, "car":null }，则响应为{ "name":"John", "age":30, "car":null }
如果MediaType.APPLICATION_XML_VALUE 用于@RequestMapping 和jackson-dataformat-xml 的produces 属性，则响应
<Map>
<name>John</name>
<age>30</age>
<car/>
</Map>
为什么使用 JAXB 会失败？
更新 01
好的，就像@Simon 评论一样，我创建了一个示例对象（类）来作为请求和响应。 效果完全相同。这是更新的代码
public class MockupResponse {
private String name;
private Integer age;
private String car;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getCar() {
return car;
}
public void setCar(String car) {
this.car = car;
}
@Override
public String toString() {
StringBuffer sb = new StringBuffer();
if (null != name)
sb.append("Name: " + name + "\n");
if (null != age)
sb.append("Age: " + age + "\n");
if (null != car)
sb.append("Car: " + car + "\n");
return sb.toString();
}
}
服务
@RequestMapping(value = "/userLogin", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_UTF8_VALUE, consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
public @ResponseBody ResponseEntity<MockupResponse> login(@RequestBody MockupResponse sample) {
System.out.println(sample);
return new ResponseEntity<MockupResponse>(sample, HttpStatus.OK);
}
【问题讨论】：
-
因为 JAXB 将对象转换为 XML 而不是映射。为什么不创建一个类而不是使用地图？
-
谢谢@SimonMartinelli 我正在寻找解释，以后可能会创建一个对象，但正如您所见，这只是一个示例代码。我认为
jackson-dataformat-xml能够将地图转换为优于 JAXB 的优势，对吧？ -
遗憾的是，用对象而不是地图更新了代码，效果完全相同。
标签： xml http spring-boot jackson jaxb