Java JSON字符串转JSON对象：三种常用方法详解

在Java中，可以使用JsonParser类或者第三方库如Gson或Jackson来将JSON字符串转换为JSON对象。\n\n使用JsonParser类:\njava\nimport com.google.gson.JsonObject;\nimport com.google.gson.JsonParser;\n\npublic class Main {\n public static void main(String[] args) {\n String jsonString = "\{"name\":\"John\", \"age\":30, \"city\":\"New York\"}";\n\n JsonParser jsonParser = new JsonParser();\n JsonObject jsonObject = jsonParser.parse(jsonString).getAsJsonObject();\n\n System.out.println(jsonObject.get("name").getAsString());\n System.out.println(jsonObject.get("age").getAsInt());\n System.out.println(jsonObject.get("city").getAsString());\n }\n}\n\n\n使用Gson库:\njava\nimport com.google.gson.Gson;\n\npublic class Main {\n public static void main(String[] args) {\n String jsonString = "\{"name\":\"John\", \"age\":30, \"city\":\"New York\"}";\n\n Gson gson = new Gson();\n JsonObject jsonObject = gson.fromJson(jsonString, JsonObject.class);\n\n System.out.println(jsonObject.get("name").getAsString());\n System.out.println(jsonObject.get("age").getAsInt());\n System.out.println(jsonObject.get("city").getAsString());\n }\n}\n\n\n使用Jackson库:\njava\nimport com.fasterxml.jackson.databind.ObjectMapper;\n\npublic class Main {\n public static void main(String[] args) {\n String jsonString = "\{"name\":\"John\", \"age\":30, \"city\":\"New York\"}";\n\n ObjectMapper objectMapper = new ObjectMapper();\n try {\n JsonNode jsonNode = objectMapper.readTree(jsonString);\n\n System.out.println(jsonNode.get("name").asText());\n System.out.println(jsonNode.get("age").asInt());\n System.out.println(jsonNode.get("city").asText());\n } catch (IOException e) {\n e.printStackTrace();\n }\n }\n}\n\n\n无论使用哪种方法，都需要导入相应的类库。以上代码将JSON字符串\{"name\":\"John\", \"age\":30, \"city\":\"New York\"}转换为JSON对象，并输出其中的属性值。