Android开源库--Gson谷歌官方json解析库

//将此json数据变成一个对象。
JSONObject jsonObject = new JSONObject(String);
//然后获得list里面的数据
JSONArray jsonArray = jsonObject.getJSONArray("list");//当不知道key时，使用循环
for(int i=;i<jsonArray.length();i++)
{
JSONObject jsonOb = (JSONObject)jsonArray.opt(i);
int tel = jsonOb.getInt("tel");
}

String myString = new JSONStringer().object().key("name").value("小猪").endObject().toString();
//结果是一组标准格式的JSON text：{"name" : "小猪"}

Gson gson = new Gson();
//序列化
MyObject myobj = new MyObject();
String jsonstr = gson .toJson(myobj);//反序列化
MyObject myobj = gson.fromJson(jsonstr, MyObject.class); //序列化数组
String[] days = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
String numbersJson = gson.toJson(numbers);//序列化集合
List<String> myobjs = new ArrayList<String>();
String jsonstr = gson.toJson(myobjs);//反序列化集合数组
List<MyObject> myobjs = gson.fromJson(str, new TypeToken<ArrayList<MyObject>>(){}.getType());

public class User {
@Expose private String firstName;
@Expose(serialize = false) private String lastName;
@Expose (serialize = false, deserialize = false) private String emailAddress;
private String password;
}

public class SomeClassWithFields {
@SerializedName("name") private final String someField;
private final String someOtherField;
public SomeClassWithFields(String a, String b) {
this.someField = a;
this.someOtherField = b;
}
}

public class Example33 {
public static void main(String[] args) {
Gson gson = new GsonBuilder().setVersion(2.0).create();
String json = gson.toJson(new ExampleClass());
System.out.println("Output for version 2.0...");
System.out.println(json); gson= new GsonBuilder().setVersion(1.0).create();
json = gson.toJson(new ExampleClass());
System.out.println("\nOutput for version 1.0...");
System.out.println(json); gson= new Gson();
json = gson.toJson(new ExampleClass());
System.out.println("\nOutput for No version set...");
System.out.println(json);
}
} class ExampleClass{
String field= "field";
// this is in version 1.0
@Since(1.0) String newField1 = "field 1";
// following will be included in the version 1.1
@Since(2.0) String newField2 = "field 2";
}

Gson gson = new GsonBuilder()
.excludeFieldsWithoutExposeAnnotation() //不导出实体中没有用@Expose注解的属性
.enableComplexMapKeySerialization() //支持Map的key为复杂对象的形式
.serializeNulls().setDateFormat("yyyy-MM-dd HH:mm:ss:SSS")//时间转化为特定格式
.setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)//会把字段首字母大写,注:对于实体上使用了@SerializedName注解的不会生效.
.setPrettyPrinting() //对json结果格式化.
.setVersion(1.0)
.disableHtmlEscaping()//默认是GSON把HTML 转义的，但也可以设置不转义
.serializeNulls()//把null值也转换，默认是不转换null值的，可以选择也转换
.create();

public class ApiResult<T> {
private int ret;
private String msg;
private T data; public int getRet() {
return ret;
} public void setRet(int ret) {
this.ret = ret;
} public String getMsg() {
return msg;
} public void setMsg(String msg) {
this.msg = msg;
} public T getData() {
return data;
} public void setData(T data) {
this.data = data;
}}

ApiResult<UserInfo> r = GsonUtils.parse(json, new TypeToken<ApiResult<UserInfo>>() {
}.getType());