Question

我使用Jackson mapper版本2.6.5和Spring Boot，但我似乎可以让SerializationFeature.INDENT_OUTPUT工作。我按照教程here进行了操作。我的代码如下。

public class SerializationExampleTreeModel {
    public static void main(String[] args) throws IOException {
        // Create the node factory that gives us nodes.
        JsonNodeFactory nodeFactory = new JsonNodeFactory(false);

        StringWriter stringWriter = new StringWriter();
        // create a json factory to write the treenode as json. for the example
        // we just write to console
        JsonFactory jsonFactory = new JsonFactory();
        JsonGenerator generator = jsonFactory.createGenerator(stringWriter);

        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(SerializationFeature.INDENT_OUTPUT, true);

        // the root node - album
        JsonNode album = nodeFactory.objectNode();

        album.put("Album-Title", "Kind Of Blue")

        ArrayNode songs = nodeFactory.arrayNode()
        songs.add("Song8").add("Song2")

        album.put("Songs", songs)

        ObjectNode artist = nodeFactory.objectNode()
        artist.put("Name", "Alex" )

        album.put( "artist", artist)


        mapper.writeTree(generator, album)

        println stringWriter.toString()


    }

}

我总是得到结果：

{"Album-Title":"Kind Of Blue","Songs":["Song8","Song2"],"artist":{"Name":"Alex"}}是否包含行mapper.configure(SerializationFeature.INDENT_OUTPUT, true)。发生了什么事？

注意：我使用groovyc编译我的代码，并且不需要使用分号。

Answer 1

问题是您使用StringWriter来编写输出，它会忽略您在ObjectMapper上按预期设置的格式。相反，使用：

System.out.println(mapper.writeValueAsString(album));

如果您喜欢使用，可以在编写树之前声明打印机：

generator.setPrettyPrinter(new DefaultPrettyPrinter());
mapper.writeTree(generator, album);

这将允许正确的输出：

stringWriter.toString()

在Jackson 2.6.5上忽略了SerializationFeature.INDENT_OUTPUT

1 个答案: