Java中的漂亮打印JSON

GSON 可以用一种很好的方式做到这一点:

Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(uglyJSONString);
String prettyJsonString = gson.toJson(je);

我用过 org.json

JSONObject json = new JSONObject(jsonString); // Convert text to object
System.out.println(json.toString(4)); // Print it with specified indentation

JSON中的字段顺序是每个定义随机的。特定的顺序取决于解析器的实现。

好像 GSON 支持此功能,但我不知道是否要从正在使用的库中切换。

从用户指南:

Gson gson = new GsonBuilder().setPrettyPrinting().create();
String jsonOutput = gson.toJson(someObject);

和杰克逊在一起( com.fasterxml.jackson.databind ):

ObjectMapper mapper = new ObjectMapper();
System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonObject))

How to enable pretty print JSON output (Jackson)

我知道答案里已经有了,但是我想在这里单独写,因为很有可能,你已经有了Jackson作为依赖项,所以你只需要一行额外的代码

如果使用Java API进行JSON处理(JSR-353)实现,则可以指定 JsonGenerator.PRETTY_PRINTING 属性创建 JsonGeneratorFactory .

以下示例最初发布在 blog post

import java.util.*;
import javax.json.Json;
import javax.json.stream.*;

Map<String, Object> properties = new HashMap<String, Object>(1);
properties.put(JsonGenerator.PRETTY_PRINTING, true);
JsonGeneratorFactory jgf = Json.createGeneratorFactory(properties);
JsonGenerator jg = jgf.createGenerator(System.out);

jg.writeStartObject()                    // {
    .write("name", "Jane Doe")           //    "name":"Jane Doe",
    .writeStartObject("address")         //    "address":{
        .write("type", 1)                //        "type":1,
        .write("street", "1 A Street")   //        "street":"1 A Street",
        .writeNull("city")               //        "city":null,
        .write("verified", false)        //        "verified":false
    .writeEnd()                          //    },
    .writeStartArray("phone-numbers")    //    "phone-numbers":[
        .writeStartObject()              //        {
            .write("number", "555-1111") //            "number":"555-1111",
            .write("extension", "123")   //            "extension":"123"
        .writeEnd()                      //        },
        .writeStartObject()              //        {
            .write("number", "555-2222") //            "number":"555-2222",
            .writeNull("extension")      //            "extension":null
        .writeEnd()                      //        }
    .writeEnd()                          //    ]
.writeEnd()                              // }
.close();

漂亮的印花 GSON 一行:

System.out.println(new GsonBuilder().setPrettyPrinting().create().toJson(new JsonParser().parse(jsonString)));

除了内联,这相当于 the accepted answer

我的情况是,我的项目使用的是不支持漂亮打印的遗留(非JSR)JSON解析器。不过,我需要生成打印精美的JSON示例;只要使用Java 7及以上版本,无需添加任何额外的库,这是可能的:

ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine scriptEngine = manager.getEngineByName("JavaScript");
scriptEngine.put("jsonString", jsonStringNoWhitespace);
scriptEngine.eval("result = JSON.stringify(JSON.parse(jsonString), null, 2)");
String prettyPrintedJson = (String) scriptEngine.get("result");

基本思想是跳转JSON中基于特殊字符的格式。例如,如果观察到“{”或“[”,代码将创建一个新行并增加缩进级别。

/**
 * A simple implementation to pretty-print JSON file.
 *
 * @param unformattedJsonString
 * @return
 */
public static String prettyPrintJSON(String unformattedJsonString) {
  StringBuilder prettyJSONBuilder = new StringBuilder();
  int indentLevel = 0;
  boolean inQuote = false;
  for(char charFromUnformattedJson : unformattedJsonString.toCharArray()) {
    switch(charFromUnformattedJson) {
      case '"':
        // switch the quoting status
        inQuote = !inQuote;
        prettyJSONBuilder.append(charFromUnformattedJson);
        break;
      case ' ':
        // For space: ignore the space if it is not being quoted.
        if(inQuote) {
          prettyJSONBuilder.append(charFromUnformattedJson);
        }
        break;
      case '{':
      case '[':
        // Starting a new block: increase the indent level
        prettyJSONBuilder.append(charFromUnformattedJson);
        indentLevel++;
        appendIndentedNewLine(indentLevel, prettyJSONBuilder);
        break;
      case '}':
      case ']':
        // Ending a new block; decrese the indent level
        indentLevel--;
        appendIndentedNewLine(indentLevel, prettyJSONBuilder);
        prettyJSONBuilder.append(charFromUnformattedJson);
        break;
      case ',':
        // Ending a json item; create a new line after
        prettyJSONBuilder.append(charFromUnformattedJson);
        if(!inQuote) {
          appendIndentedNewLine(indentLevel, prettyJSONBuilder);
        }
        break;
      default:
        prettyJSONBuilder.append(charFromUnformattedJson);
    }
  }
  return prettyJSONBuilder.toString();
}

/**
 * Print a new line with indention at the beginning of the new line.
 * @param indentLevel
 * @param stringBuilder
 */
private static void appendIndentedNewLine(int indentLevel, StringBuilder stringBuilder) {
  stringBuilder.append("\n");
  for(int i = 0; i < indentLevel; i++) {
    // Assuming indention using 2 spaces
    stringBuilder.append("  ");
  }
}

一行:

String niceFormattedJson = JsonWriter.formatJson(jsonString)

json io库( https://github.com/jdereg/json-io

除了漂亮地打印JSON之外,您还可以将Java对象(整个Java对象图和循环)序列化为JSON,并将其读入。

在JSONLib中,您可以使用:

String jsonTxt = JSONUtils.valueToString(json, 8, 4);

从 Javadoc

现在,这可以通过JSONLib库实现:

http://json-lib.sourceforge.net/apidocs/net/sf/json/JSONObject.html

如果(并且仅当)使用重载 toString(int indentationFactor) 方法而不是标准 toString() 方法。

<dependency>
  <groupId>org.json</groupId>
  <artifactId>json</artifactId>
  <version>20140107</version>
</dependency>

遵循JSON-P 1.0规范( JSR-353 )对于给定的 JsonStructure JsonObject 或 JsonArray

import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;

import javax.json.Json;
import javax.json.JsonStructure;
import javax.json.JsonWriter;
import javax.json.JsonWriterFactory;
import javax.json.stream.JsonGenerator;

public class PrettyJson {

    private static JsonWriterFactory FACTORY_INSTANCE;

    public static String toString(final JsonStructure status) {

        final StringWriter stringWriter = new StringWriter();

        final JsonWriter jsonWriter = getPrettyJsonWriterFactory()
                .createWriter(stringWriter);

        jsonWriter.write(status);
        jsonWriter.close();

        return stringWriter.toString();
    }

    private static JsonWriterFactory getPrettyJsonWriterFactory() {
        if (null == FACTORY_INSTANCE) {
            final Map<String, Object> properties = new HashMap<>(1);
            properties.put(JsonGenerator.PRETTY_PRINTING, true);
            FACTORY_INSTANCE = Json.createWriterFactory(properties);
        }
        return FACTORY_INSTANCE;
    }

}

你可以像下面这样使用Gson

Gson gson = new GsonBuilder().setPrettyPrinting().create();
String jsonString = gson.toJson(object);

从岗位上 JSON pretty print using Gson

ObjectMapper mapper = new ObjectMapper();
String perttyStr = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(object);

从岗位上 Pretty print JSON in Java (Jackson)

希望能帮上忙!

mapper.writerWithDefaultPrettyPrinter().writeValueAsString(JSONString)

Underscore-java 有静态方法 U.formatJson(json) . 我是这个项目的维护者。 Live example

import com.github.underscore.lodash.U;

public class MyClass {

    public static void main(String args[]) {
        String json = "{\"Price\": {"
        + "    \"LineItems\": {"
        + "        \"LineItem\": {"
        + "            \"UnitOfMeasure\": \"EACH\", \"Quantity\": 2, \"ItemID\": \"ItemID\""
        + "        }"
        + "    },"
        + "    \"Currency\": \"USD\","
        + "    \"EnterpriseCode\": \"EnterpriseCode\""
        + "}}";
        System.out.println(U.formatJson(json)); 
    }
}

{
   "Price": {
      "LineItems": {
         "LineItem": {
            "UnitOfMeasure": "EACH",
            "Quantity": 2,
            "ItemID": "ItemID"
         }
      },
      "Currency": "USD",
      "EnterpriseCode": "EnterpriseCode"
   }
}