杰克逊无法访问com.fasterxml.jackson.core.ObjectCodec [英] Jackson cannot access com.fasterxml.jackson.core.ObjectCodec

问题描述

此问题是对此问题的跟进。 。我似乎无法在以下代码中访问jackson库：

This question is a follow up to this one. I can't seem to be able to access the jackson library in the following code:

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.fasterxml.jackson.databind.ObjectWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class ServerConfiguration {
    public String info = null;
    public String idlURL = null;
    public String idlContents = null;
    public List<ServerInfo> servers = new ArrayList<>();

    public final void clear() {
        info = null;
        idlURL = null;
        idlContents = null;
        if (servers != null)
            servers.clear();
    }

    private final static ObjectReader jsonReader;
    private final static ObjectWriter jsonWriter;

    static {
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true); // <== Error:(52, 15) java: cannot access com.fasterxml.jackson.core.JsonGenerator class file for com.fasterxml.jackson.core.JsonGenerator not found
        //mapper.configure(SerializationFeature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED, true);
        jsonWriter = mapper.writer();
        jsonReader = mapper.reader(ServerConfiguration.class);
    }

    public static ServerConfiguration fromJson(String json) throws IOException {
        return jsonReader.<ServerConfiguration>readValue(json); // <== Error:(59, 26) java: cannot access com.fasterxml.jackson.core.JsonProcessingException class file for com.fasterxml.jackson.core.JsonProcessingException not found
    }

    public String toJson() throws IOException {
        return jsonWriter.writeValueAsString(this);
    }

}

尽管jar文件在classpath（autocomplete显示Intellij中的方法声明）。

eventhough the jar files are in the classpath(autocomplete shows the method declaration in Intellij).

我缺少什么？

推荐答案

当我遇到这个问题时我的类路径中有 jackson-annotations 和 jackson-databind 罐子，但不是 jackson-core 。

When I had this problem I had the jackson-annotations and jackson-databind jars in my classpath, but not jackson-core.

在类路径中添加jackson-core解决了它。

Adding jackson-core to the classpath solved it for me.

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