1 使用阿里的FastJson

1.1 项目的pom.xml依赖

 com.alibaba
 fastjson
 1.2.58

1.2 Java示例代码

(1) 导入的包:

com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.serializer.SerializerFeature;

(2) 测试代码:

其中JSON字符串为:

{"_index":"book_shop","_type":"it_book","_id":"1","_score":1.0,"_source":{"name": "Java编程思想（第4版）","author": "[美] Bruce Eckel","category": "编程语言","price": 109.0,"publisher": "机械工业出版社","date": "2007-06-01","tags": [ "Java", "编程语言" ]}}

public static void main(String[] args) {

 String jsonString = "{\"_index\":\"book_shop\",\"_type\":\"it_book\",\"_id\":\"1\",\"_score\":1.0," +
   "\"_source\":{\"name\": \"Java编程思想（第4版）\",\"author\": \"[美] Bruce Eckel\",\"category\": \"编程语言\"," +
   "\"price\": 109.0,\"publisher\": \"机械工业出版社\",\"date\": \"2007-06-01\",\"tags\": [ \"Java\", \"编程语言\" ]}}";

 JSONObject object = JSONObject.parseObject(jsonString);
 String pretty = JSON.toJSONString(object, SerializerFeature.PrettyFormat, SerializerFeature.WriteMapNullValue, 
   SerializerFeature.WriteDateUseDateFormat);

 System.out.println(pretty);
}

(3) 格式化输出后的结果:

说明: FastJson通过Tab键进行换行后的格式化.

{
 "_index":"book_shop",
 "_type":"it_book",
 "_source":{
 "date":"2007-06-01",
 "author":"[美] Bruce Eckel",
 "price":109.0,
 "name":"Java编程思想（第4版）",
 "publisher":"机械工业出版社",
 "category":"编程语言",
 "tags":[
 "Java",
 "编程语言"
 ]
 },
 "_id":"1",
 "_score":1.0
}

2 使用谷歌的Gson

2.1 项目的pom.xml依赖

 com.google.code.gson
 gson
 2.2.4

2.2 Java示例代码

(1) 导入的包:

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

(2) 测试代码:

JSON字符串与上述测试代码相同.

public static void main(String[] args) {
 
 String jsonString = "{\"_index\":\"book_shop\",\"_type\":\"it_book\",\"_id\":\"1\",\"_score\":1.0," +
   "\"_source\":{\"name\": \"Java编程思想（第4版）\",\"author\": \"[美] Bruce Eckel\",\"category\": \"编程语言\"," +
   "\"price\": 109.0,\"publisher\": \"机械工业出版社\",\"date\": \"2007-06-01\",\"tags\": [ \"Java\", \"编程语言\" ]}}";
 
 String pretty = toPrettyFormat(jsonString) 
 System.out.println(pretty);
}

/**
 * 格式化输出JSON字符串
 * @return 格式化后的JSON字符串
 */
private static String toPrettyFormat(String json) {
 JsonParser jsonParser = new JsonParser();
 JsonObject jsonObject = jsonParser.parse(json).getAsJsonObject();
 Gson gson = new GsonBuilder().setPrettyPrinting().create();
 return gson.toJson(jsonObject);
}

(3) 格式化输出后的结果:

说明: Gson使用2个空格作为换行后的格式转换.

{
 "_index": "book_shop",
 "_type": "it_book",
 "_id": "1",
 "_score": 1.0,
 "_source": {
 "name": "Java编程思想（第4版）",
 "author": "[美] Bruce Eckel",
 "category": "编程语言",
 "price": 109.0,
 "publisher": "机械工业出版社",
 "date": "2007-06-01",
 "tags": [
  "Java",
  "编程语言"
 ]
 }
}