最简单的方法: 使用gson，谷歌自己的goto json库。https://code.google.com/p/google-gson/

这是一个样品。我到这个免费的地理定位器网站，解析json，显示邮政编码。(只要把这些东西放在主方法中测试就可以了)

    String sURL = "http://freegeoip.net/json/"; //just a string

    // Connect to the URL using java's native library
    URL url = new URL(sURL);
    URLConnection request = url.openConnection();
    request.connect();

    // Convert to a JSON object to print data
    JsonParser jp = new JsonParser(); //from gson
    JsonElement root = jp.parse(new InputStreamReader((InputStream) request.getContent())); //Convert the input stream to a json element
    JsonObject rootobj = root.getAsJsonObject(); //May be an array, may be an object. 
    String zipcode = rootobj.get("zip_code").getAsString(); //just grab the zipcode

如果你不介意使用几个库，它可以在一行中完成。

包括Apache Commons IOUtils和json.org库。

JSONObject json = new JSONObject(IOUtils.toString(new URL("https://graph.facebook.com/me"), Charset.forName("UTF-8")));

Maven的依赖:

<dependency>
  <groupId>commons-io</groupId>
  <artifactId>commons-io</artifactId>
  <version>2.7</version>
</dependency>

我不确定这是否有效，但这是一种可能的方法:

使用url. openstream()从url读取json，并将内容读入字符串。

用这个字符串构造一个JSON对象(更多信息请访问json.org)

JSONObject(java.lang.String source)
      Construct a JSONObject from a source JSON text string.

以下是Jackson的几个替代版本(因为有不止一种方法你可能想要数据为):

  ObjectMapper mapper = new ObjectMapper(); // just need one
  // Got a Java class that data maps to nicely? If so:
  FacebookGraph graph = mapper.readValue(url, FaceBookGraph.class);
  // Or: if no class (and don't need one), just map to Map.class:
  Map<String,Object> map = mapper.readValue(url, Map.class);

特别是通常(IMO)的情况下，你想要处理Java对象，可以做成一行:

FacebookGraph graph = new ObjectMapper().readValue(url, FaceBookGraph.class);

其他库，如Gson也支持单行方法;为什么很多例子都显示了更长的部分，这很奇怪。更糟糕的是，许多例子使用了过时的org。json库;它可能是首选，但有6个更好的选择，所以几乎没有理由使用它。

下面是如何解析Json内容的完整示例。该示例获取Android版本统计信息(从Android Studio源代码中找到，链接到这里)。

复制“发行版”。Json”文件，你从那里得到的res/raw，作为一个后备。

build.gradle

    implementation 'com.google.code.gson:gson:2.8.6'

清单

  <uses-permission android:name="android.permission.INTERNET" />

MainActivity.kt

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        if (savedInstanceState != null)
            return
        thread {
            // https://cs.android.com/android/platform/superproject/+/studio-master-dev:tools/adt/idea/android/src/com/android/tools/idea/stats/DistributionService.java
            var root: JsonArray
            Log.d("AppLog", "loading...")
            try {
                HttpURLConnection.setFollowRedirects(true)
                val statsUrl = "https://dl.google.com/android/studio/metadata/distributions.json" //just a string
                val url = URL(statsUrl)
                val request: HttpURLConnection = url.openConnection() as HttpURLConnection
                request.connectTimeout = 3000
                request.connect()
                InputStreamReader(request.content as InputStream).use {
                    root = JsonParser.parseReader(it).asJsonArray
                }
            } catch (e: Exception) {
                Log.d("AppLog", "error while loading from Internet, so using fallback")
                e.printStackTrace()
                InputStreamReader(resources.openRawResource(R.raw.distributions)).use {
                    root = JsonParser.parseReader(it).asJsonArray
                }
            }
            val decimalFormat = DecimalFormat("0.00")
            Log.d("AppLog", "result:")

            root.forEach {
                val androidVersionInfo = it.asJsonObject
                val versionNickName = androidVersionInfo.get("name").asString
                val versionName = androidVersionInfo.get("version").asString
                val versionApiLevel = androidVersionInfo.get("apiLevel").asInt
                val marketSharePercentage = androidVersionInfo.get("distributionPercentage").asFloat * 100f
                Log.d("AppLog", "\"$versionNickName\" - $versionName - API$versionApiLevel - ${decimalFormat.format(marketSharePercentage)}%")
            }
        }
    }
}

作为依赖项的替代，你也可以使用这个:

InputStreamReader(request.content as InputStream).use {
    val jsonArray = JSONArray(it.readText())
}

还有备用方案:

InputStreamReader(resources.openRawResource(R.raw.distributions)).use {
    val jsonArray = JSONArray(it.readText())
}

运行的结果:

loading...
result:
"Ice Cream Sandwich" - 4.0 - API15 - 0.20%
"Jelly Bean" - 4.1 - API16 - 0.60%
"Jelly Bean" - 4.2 - API17 - 0.80%
"Jelly Bean" - 4.3 - API18 - 0.30%
"KitKat" - 4.4 - API19 - 4.00%
"Lollipop" - 5.0 - API21 - 1.80%
"Lollipop" - 5.1 - API22 - 7.40%
"Marshmallow" - 6.0 - API23 - 11.20%
"Nougat" - 7.0 - API24 - 7.50%
"Nougat" - 7.1 - API25 - 5.40%
"Oreo" - 8.0 - API26 - 7.30%
"Oreo" - 8.1 - API27 - 14.00%
"Pie" - 9.0 - API28 - 31.30%
"Android 10" - 10.0 - API29 - 8.20%

最简单的方法: 使用gson，谷歌自己的goto json库。https://code.google.com/p/google-gson/

这是一个样品。我到这个免费的地理定位器网站，解析json，显示邮政编码。(只要把这些东西放在主方法中测试就可以了)

    String sURL = "http://freegeoip.net/json/"; //just a string

    // Connect to the URL using java's native library
    URL url = new URL(sURL);
    URLConnection request = url.openConnection();
    request.connect();

    // Convert to a JSON object to print data
    JsonParser jp = new JsonParser(); //from gson
    JsonElement root = jp.parse(new InputStreamReader((InputStream) request.getContent())); //Convert the input stream to a json element
    JsonObject rootobj = root.getAsJsonObject(); //May be an array, may be an object. 
    String zipcode = rootobj.get("zip_code").getAsString(); //just grab the zipcode