你可以像下面这样使用Gson

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

从post JSON漂亮打印使用Gson

或者，你可以像下面这样使用Jackson

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

漂亮的Java JSON打印(Jackson)

希望这对你有所帮助!

java有一个静态方法U.formatJson(json)。 支持5种格式类型:2,3,4，制表符和压缩。生活的例子

import com.github.underscore.U;

import static com.github.underscore.Json.JsonStringBuilder.Step.TABS;
import static com.github.underscore.Json.JsonStringBuilder.Step.TWO_SPACES;

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, TWO_SPACES)); 
        System.out.println(U.formatJson(json, TABS)); 
    }
}

输出:

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

I also use the org.json.simple package. I have simply coded the formatter, but since I don't have nulls, numbers or booleans in my JSON objects in the program that I wrote, I only coded for strings, objects and arrays. If anyone is interested, let this just be in the public domain. You are welcome to add the missing data types (where it says in the comment "it's a string"). Also, you can add the indentation as a parameter whereas mine is just two spaces. Please reshare after you've tested your improvements.

用法： printJsonObject（jsonObject， “”）;

功能:

    public static void printJsonObject(JSONObject object, String prefix) {
        boolean notFirst = false;
        System.out.println(prefix + "{");
        for (Object key : object.keySet()) {
            if (notFirst) {
                System.out.println(", ");
            }
            notFirst = true;
            Object value = object.get(key);
            System.out.print(prefix + "  " + "\"" + key + "\"" + ": ");
            if (value instanceof JSONObject) {
                printJsonObject((JSONObject) value, prefix + "  ");
            } else if (value instanceof JSONArray) {
                printJsonArray((JSONArray) value, prefix + "  ");
            } else {  // it's a string
                System.out.print("\"" + value + "\"");
            }
        }
        System.out.println("");
        System.out.print(prefix + "}");
    }

    public static void printJsonArray(JSONArray array, String prefix) {
        boolean notFirst = false;
        System.out.println("[");
        for (Object item : array) {
            if (notFirst) {
                System.out.println(", ");
            }
            notFirst = true;
            if (item instanceof JSONObject) {
                printJsonObject((JSONObject) item, prefix + "  ");
            } else if (item instanceof JSONArray) {
                printJsonArray((JSONArray) item, prefix + "  ");
            } else {
                System.out.print(prefix + "  " + "\"" + item + "\"");
            }
        }
        System.out.println("");
        System.out.print(prefix + "]");
    }

你可以使用小的json库

String jsonstring = ....;
JsonValue json = JsonParser.parse(jsonstring);
String jsonIndendedByTwoSpaces = json.toPrettyString("  ");

GSON似乎支持这一点，尽管我不知道您是否想从正在使用的库切换。

来自用户指南:

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

现在这可以通过JSONLib库实现:

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

当(且仅当)你使用重载的toString(int indentationFactor)方法而不是标准的toString()方法。

我已经在以下版本的API上验证了这一点:

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