Java Spring POST API json 输入

Question

首次开发基于java spring的API。这些 API 将采用 POST 方式并采用 JSON 作为输入。我不能连接所有点，因为当我从其余客户端调用 api 调用时会出现错误消息。

pom.xml

      <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.5.3</version>
    </dependency>

从 json 序列化的对象

public class PostCountry {
    private String country;


    public void setCountry(String country){
        this.country=country;
    }
    public String getCountry() {
        return country;
    }

}

Controller

@RequestMapping(value = "/getCountries", method = RequestMethod.POST, consumes = "application/json")
    public @ResponseBody String getCountries(PostCountry country) {
        System.out.println(country.getCountry());
        MapDAOImpl mapDAOImpl = (MapDAOImpl) appContext.getBean("mapDAOImpl");
        System.out.println(mapDAOImpl.getCountries(country.getCountry()));
        return "";

    }

休息客户端抛出错误消息

<u>The server refused this request because the request entity is in a format not supported by the requested resource for the requested method.</u>

错误

System.out.println(country.getCountry()); is null

Answer 1

问题有 2 倍。我需要在 xml 文件中定义一些 RequestMappingHandlerAdapter。

  <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <property name="messageConverters">
            <list>
                <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
                <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/>
                <bean class="org.springframework.http.converter.xml.SourceHttpMessageConverter"/>
                <bean class="org.springframework.http.converter.FormHttpMessageConverter"/>
                <bean class="org.springframework.http.converter.StringHttpMessageConverter"/>
            </list>
        </property>
    </bean>

并在模型中定义一个空的构造函数

public class PostCountry {


    public String country;

    public PostCountry() {}

    public PostCountry(String country) {
        this.country = country;
    }

    public void setCountry(String country){
        this.country=country;
    }
    public String getCountry() {
        return country;
    }

}




@RequestMapping(value = "/getCountries"                                    
        , method = RequestMethod.POST                                      
        , consumes = "application/json"                                    
        , produces = "application/json")                                   
@ResponseBody                                                              
@JsonIgnoreProperties(ignoreUnknown = true)                                
public ReturnCountries getCountries(@RequestBody PostCountry country) {