在JSONLib中，你可以这样使用:

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

来自Javadoc:

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!

漂亮的打印与GSON一行:

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

除了内联之外，这等价于已接受的答案。

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 + "]");
    }

与杰克逊(com.fasterxml.jackson.databind):

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

如何启用漂亮的JSON打印输出(Jackson)

我知道这已经在答案中，但我想在这里单独写它，因为很可能您已经将Jackson作为依赖项，因此您需要的只是额外的一行代码

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"
    }
}