使用Spring RestTemplate解析Json文件

我有一个基本的SpringBoot应用程序。使用Spring初始化程序，嵌入式Tomcat，Thymeleaf模板引擎和包作为可执行JAR。使用Spring RestTemplate解析Json文件

我连接到URL并打印响应：

BufferedReader br = new BufferedReader(new InputStreamReader(
       (conn.getInputStream()))); 

     StringBuilder response = new StringBuilder(""); 
     String output; 
     while ((output = br.readLine()) != null) { 
      response.append(output); 
     }

这个结果：

{"data":[{"device":"18AE63","time":1494516023,"data":"3235","snr":"36.72","linkQuality":"GOOD"},{"device":"18AE63","time":1494515750,"data":"484f4c41","snr":"35.69","linkQuality":"GOOD"}],"paging":{}}

但是当我使用RestTemplate

RestTemplate restTemplate = new RestTemplate(); 

     List<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>();   
     MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter(); 

     converter.setSupportedMediaTypes(Arrays.asList(MediaType.ALL));   
     messageConverters.add(converter); 
     restTemplate.setMessageConverters(messageConverters); 

     MessageList messageList = 
        restTemplate.getForObject(url, MessageList.class);

我得到这个错误：

Exception in thread "main" org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON document: Unexpected character ('<' (code 60)): expected a valid value (number, String, array, object, 'true', 'false' or 'null') 
at [Source: [email protected]; line: 1, column: 2]; nested exception is com.fasterxml.jackson.core.JsonParseException: Unexpected character ('<' (code 60)): expected a valid value (number, String, array, object, 'true', 'false' or 'null') 
at [Source: [email protected]; line: 1, column: 2] 
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:234) 
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:219) 
    at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:95) 
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:655) 
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:613) 
    at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:287) 
    at com.tdk.web.controllers.restful.client.RestTemplateGETExample.main(RestTemplateGETExample.java:49) 
Caused by: com.fasterxml.jackson.core.JsonParseException: Unexpected character ('<' (code 60)): expected a valid value (number, String, array, object, 'true', 'false' or 'null') 
at [Source: [email protected]; line: 1, column: 2] 
    at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1702) 
    at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:558) 
    at com.fasterxml.jackson.core.base.ParserMinimalBase._reportUnexpectedChar(ParserMinimalBase.java:456) 
    at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._handleUnexpectedValue(UTF8StreamJsonParser.java:2689) 
    at com.fasterxml.jackson.core.json.UTF8StreamJsonParser._nextTokenNotInObject(UTF8StreamJsonParser.java:878) 
    at com.fasterxml.jackson.core.json.UTF8StreamJsonParser.nextToken(UTF8StreamJsonParser.java:772) 
    at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:3834) 
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3783) 
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2922) 
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:231) 
    ... 6 more

的POJO：

@JsonInclude(JsonInclude.Include.NON_NULL) 
@JsonPropertyOrder({ 
"data", 
"paging" 
}) 
public class MessageList { 

    @JsonProperty("data") 
    private List<Message> data = null; 
    @JsonProperty("paging") 
    private Paging paging; 
    @JsonIgnore 
    private Map<String, Object> additionalProperties = new HashMap<String, Object>(); 

    @JsonProperty("data") 
    public List<Message> getData() { 
    return data; 
    } 

    @JsonProperty("data") 
    public void setData(List<Message> data) { 
    this.data = data; 
    } 

    @JsonProperty("paging") 
    public Paging getPaging() { 
    return paging; 
    } 

    @JsonProperty("paging") 
    public void setPaging(Paging paging) { 
    this.paging = paging; 
    } 

    @JsonAnyGetter 
    public Map<String, Object> getAdditionalProperties() { 
    return this.additionalProperties; 
    } 

    @JsonAnySetter 
    public void setAdditionalProperty(String name, Object value) { 
    this.additionalProperties.put(name, value); 
    } 

    @Override 
    public String toString() { 
     return "MessageList [data=" + data + ", paging=" + paging + ", additionalProperties=" + additionalProperties 
       + "]"; 
    } 
}

来源

2017-05-27 En NuNYet de Can CalÇadA

Spring引导将设置所有标准的消息转换器，如果你只需要json反序列化，你需要的只是一个正确构造的匹配json响应的POJO。你可以发布你的pojo吗？ –

消息说，您的响应将意外字符'<'当作RestTemplate尝试将响应解析为JSON。但是你提供了一个有效的json。我想你错过了一些东西...... – Zico

你得到的响应是HTML，而不是JSON。

JsonParseException: Unexpected character ('<' (code 60))

这通常意味着你的HTTP调用了一个HTML错误响应（认为<html><h1>404 Not Found</h1>...</html>），因此JSON解析器抱怨的反应不是有效的JSON。

来源

2017-08-18 11:57:48 walen

使用Spring RestTemplate解析Json文件

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