然后，我试图使用杰克逊API来解析json输入流两次，我得到一个java.io.EOFException

Question

My ParserCheck.java:-

import java.io.IOException;
import java.io.InputStream;        
import org.apache.commons.io.IOUtils;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
public class ParserCheck {
    public static void main(String[] args){
        ObjectMapper objectMapper = new ObjectMapper();
        String responseJson = "{"status":"200","message":"Success"}";
        InputStream streamResponse = IOUtils.toInputStream(responseJson);
        try {
            MyJsonResponse response = objectMapper.readValue(streamResponse, MyJsonResponse.class);
            System.out.println(response);
        } catch ( JsonParseException | JsonMappingException e) {
            e.printStackTrace();
        } catch (IOException e){
            e.printStackTrace();
        }
        try {
            MyJsonResponse response = objectMapper.readValue(streamResponse, MyJsonResponse.class);
            System.out.println(response);
        } catch ( JsonParseException | JsonMappingException e) {
            e.printStackTrace();
        } catch (IOException e){
            e.printStackTrace();
        }finally{
            try {
                streamResponse.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

我JsonResponse.java

:

import org.codehaus.jackson.annotate.JsonIgnoreProperties;
import org.codehaus.jackson.annotate.JsonProperty;
import org.codehaus.jackson.map.annotate.JsonSerialize;
@JsonIgnoreProperties(ignoreUnknown=true)
@JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)
public class MyJsonResponse {
    @JsonProperty
    private Integer status;
    @JsonProperty
    private String message;
    public Integer getStatus() {
        return status;
    }
    public String getMessage() {
        return message;
    }
    @Override
    public String toString(){
        return "Json Response [Status ="+ status +", Message =" + message + " ]";
    }
}

第一次得到正确的输出，但第二次得到异常。这是输出:

Json Response [Status =200, Message =Success ]java.io.EOFException: No content to map to Object due to end of input
    at org.codehaus.jackson.map.ObjectMapper._initForReading(ObjectMapper.java:2775)
    at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2718)
    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1909)
    at.service.provider.ParserCheck.main(ParserCheck.java:33)

在这种情况下应该做什么?我尝试在第一个输出后关闭流，但它仍然给我异常。

Answer 1

您正在重用流。第一次调用

objectMapper.readValue(streamResponse, MyJsonResponse.class);

读取流到末尾，所以当您第二次调用它时，流没有更多的内容。如。

stremResponse.read() returns -1

使用流有什么原因吗?I tried:

            MyJsonResponse response = objectMapper.readValue(responseJson, MyJsonResponse.class);