问题描述
我写了这段代码:
ObjectMapper mapper = new ObjectMapper();
ObjectWriter writer = mapper.writer(new DefaultPrettyPrinter());
try
{
writer.writeValue(new File(jsonFile.getAbsolutePath()),jsonData);
}
catch (IOException e)
{
}
我得到的结果是:
{
"type" : "aaa","key" : {
"key1" : "bbb","key 2" : [ {
"value" : "xx"
},{
"value" : "sss"
},{
"value" : "zzz"
}]
}
}
我希望内容为:
{
"type" : "aaa","key" :
{
"key1" : "bbb","key 2" :
[
{
"value" : "xx"
},{
"value" : "sss"
},{
"value" : "zzz"
}
]
}
}
我希望它在任何括号中都带有下划线,并且兼容的制表符数量。 如何在Json字段之间添加换行符和适当的选项卡?
解决方法
我认为您不能仅通过配置漂亮的打印机来实现此目的,您将必须为此实现自己的类。参见https://fasterxml.github.io/jackson-core/javadoc/2.8/com/fasterxml/jackson/core/PrettyPrinter.html
,要实现这种格式,您需要实现自己的PrettyPrinter
:
class ObjectArrayInNewLinePrettyPrinter extends DefaultPrettyPrinter {
public ObjectArrayInNewLinePrettyPrinter() {
super();
}
public ObjectArrayInNewLinePrettyPrinter(DefaultPrettyPrinter base) {
super(base);
}
@Override
public void writeStartObject(JsonGenerator g) throws IOException {
_objectIndenter.writeIndentation(g,_nesting);
super.writeStartObject(g);
}
@Override
public void writeStartArray(JsonGenerator g) throws IOException {
_arrayIndenter.writeIndentation(g,_nesting);
super.writeStartArray(g);
}
@Override
public DefaultPrettyPrinter createInstance() {
return new ObjectArrayInNewLinePrettyPrinter(this);
}
}
您可以按以下方式使用它:
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.util.DefaultIndenter;
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.json.JsonMapper;
import java.io.File;
import java.io.IOException;
public class JsonPrettyPrinterApp {
public static void main(String[] args) throws IOException {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
DefaultPrettyPrinter printer = new ObjectArrayInNewLinePrettyPrinter();
printer.indentArraysWith(new DefaultIndenter());
JsonMapper mapper = JsonMapper.builder()
.enable(SerializationFeature.INDENT_OUTPUT)
.defaultPrettyPrinter(printer)
.build();
JsonNode root = mapper.readTree(jsonFile);
mapper.writeValue(System.out,root);
}
}
以上代码打印:
{
"type" : "aaa","key" :
{
"key1" : "bbb","key 2" :
[
{
"value" : "xx"
},{
"value" : "sss"
},{
"value" : "zzz"
}
]
}
}
打印出与您想要的东西相似的东西。