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Android框架-Google官方Gson解析

Gson gson = new Gson();  //可以通过GsonBuilder配置多种选项  gson = new GsonBuilder()          .setLenient()// json宽松          .enableComplexMapKeySerialization()//支持Map的key为复杂对象的形式          .serializeNulls() //智能null          .setPrettyPrinting()// 调教格式          .disableHtmlEscaping() //默认是GSON把HTML 转义的          .create();

public class Person {      private int per_id;      private String name;      private String sex;      private int age;      public Person(int per_id, String name, String sex, int age) {          this.per_id = per_id;          this.name = name;          this.sex = sex;          this.age = age;      }      //get、set和toString方法...  }

public class GsonTest {      public static void main(String[] args) {          Gson gson = new Gson();          // 可以通过GsonBuilder配置多种选项          gson = new GsonBuilder()                  .setLenient()// json宽松                  .enableComplexMapKeySerialization()// 支持Map的key为复杂对象的形式                  .serializeNulls() // 智能null                  .setPrettyPrinting()// 调教格式                  .disableHtmlEscaping() // 默认是GSON把HTML 转义的                  .create();          Person person = new Person(10, "layne", "man", 18);          // 对象转换为json字符串          String str = gson.toJson(person);          System.out.println("对象转换为json字符串:" + str);          // json字符串转化为对象          Person person1 = gson.fromJson(str, Person.class);          System.out.println("json字符串转化为对象:" + person1.toString());      }  }

public class CollectionTest {      public static void main(String[] args) {          Gson gson = new Gson();          // 1.1、List字符串集合转换为字符串          ArrayList<String> str_list = new ArrayList<>();          for (int i = 0; i < 5; i++) {              str_list.add("这是字符串" + i);          }          String json_str = gson.toJson(str_list);          System.out.println("这是list字符串集合转化为json：" + json_str);          // 1.2、这是json集合转化为list字符集合          Type type = new TypeToken<ArrayList<String>>() {          }.getType();          ArrayList<String> sList = gson.fromJson(json_str, type);          System.out.println("这是json集合转化为list字符集合：" + sList);          System.out.println("==========================================");          // 2.1、List对象集合转换为字符串          List<Person> list = new ArrayList<>();          for (int i = 0; i < 2; i++) {              Person person = new Person(i, "layne", "man", 18);              list.add(person);          }          String json_str1 = gson.toJson(list);          System.out.println("这是list对象集合转化为json：" + json_str1);          // 2.1、这是json转化为List对象集合          Type type1 = new TypeToken<ArrayList<Person>>() {          }.getType();          ArrayList<String> sList1 = gson.fromJson(json_str1, type1);          System.out.println("这是json转化为List对象集合：" + sList1);          System.out.println("==========================================");          //3.1、这是map集合转化为json          Map<String, Object> map = new HashMap<>();          map.put("per_id", 5);          map.put("name", "layne");          map.put("sex", "man");          map.put("age", "18");          String json_str2 = gson.toJson(map);          System.out.println("这是map集合转化为json：" + json_str2);          //3.2、从json字符串转化为map集合          Type type2 = new TypeToken<Map<String, Object>>() {          }.getType();          Map<String, Object> map1 = gson.fromJson(json_str2, type2);          System.out.println("这是json转化为map集合：" + map1);      }  }

public class JsonTest {      public static void main(String[] args) {          // JsonNull jsonNull = new JsonNull();// 构造方法过时，推荐INSTANCE          JsonNull jsonNull = JsonNull.INSTANCE;          System.out.println("JsonNull:" + jsonNull);          Gson gson = new Gson();          Person person = new Person(1, "layne", "man", 18);          String json_str = gson.toJson(person);          System.out.println("json字符串：" + json_str);          JsonPrimitive jsonPrimitive = new JsonPrimitive(json_str);          System.out.println("JsonPrimitive字符串：" + jsonPrimitive);// 多了转义字符，以及头尾的双引号："{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"age\":18}"          System.out.println("JsonPrimitive字符串：" + jsonPrimitive.getAsString());        }  }

public class AnnotationTest {      public class Person {          private int per_id;          private String name;          private String sex;          @SerializedName("case")          private int case_num;          public Person(int per_id, String name, String sex, int case_num) {              super();              this.per_id = per_id;              this.name = name;              this.sex = sex;              this.case_num = case_num;          }          @Override          public String toString() {              return "Person-->[per_id=" + per_id + ", name=" + name + ", sex="                      + sex + ", case_num=" + case_num + "]";          }      }      public static void main(String[] args) {          Gson gson = new Gson();          String json_str = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"case\":18}";          Person person = gson.fromJson(json_str, Person.class);          System.out.println("服务端发送的情况："+json_str);          System.out.println("移动端转换的情况："+person);      }  }

public class AnnotationTest1 {      public class Person {          private int per_id;          private String name;          private String sex;          @SerializedName("home_light_state")          private boolean state;          public Person(int per_id, String name, String sex, boolean state) {              super();              this.per_id = per_id;              this.name = name;              this.sex = sex;              this.state = state;          }          @Override          public String toString() {              return "Person [per_id=" + per_id + ", name=" + name + ", sex="                      + sex + ", state=" + state + "]";          }      }      public static void main(String[] args) {          Gson gson = new Gson();          String json_str = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"home_light_state\":true}";          Person person = gson.fromJson(json_str, Person.class);          System.out.println("服务端发送的情况："+json_str);          System.out.println("移动端转换的情况："+person);      }  }

public class AnnotationTest2 {      public class Person {          private int per_id;          private String name;          private String sex;          @SerializedName(value = "state", alternate = { "plus", "all" })          private String state;          public Person(int per_id, String name, String sex, String state) {              super();              this.per_id = per_id;              this.name = name;              this.sex = sex;              this.state = state;          }          @Override          public String toString() {              return "Person [per_id=" + per_id + ", name=" + name + ", sex="                      + sex + ", state=" + state + "]";          }      }      public static void main(String[] args) {          Gson gson = new Gson();          String json_str = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"all\":\"广东广州\"}";          Person person = gson.fromJson(json_str, Person.class);          System.out.println("服务端发送："+json_str);          System.out.println("转换成:" + person);          System.out.println("==========================");          String json_str1 = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"plus\":\"广东广州\"}";          Person person1 = gson.fromJson(json_str1, Person.class);          System.out.println("服务端发送："+json_str1);          System.out.println("转换成:" + person1);          System.out.println("==========================");          //all在state之后，所以all会解析成state，值则是all的原先的值          String json_str2 = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"state\":\"state广东广州\",\"all\":\"all广东广州\"}";          Person person2 = gson.fromJson(json_str2, Person.class);          System.out.println("服务端发送："+json_str2);          System.out.println("转换成:" + person2);          System.out.println("==========================");          //state在最后，不用解析，解析后的值也是state原先的          String json_str3 = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"plus\":\"plus广东广州\",\"state\":\"all广东广州\"}";          Person person3 = gson.fromJson(json_str3, Person.class);          System.out.println("服务端发送："+json_str3);          System.out.println("转换成:" + person3);          System.out.println("==========================");      }  }

@Retention(RetentionPolicy.RUNTIME)  @Target(ElementType.FIELD)  public @interface Expose {    public boolean serialize() default true;    public boolean deserialize() default true;  }

Gson gson = new GsonBuilder()                  .excludeFieldsWithoutExposeAnnotation()                  .create();

public class ExposeTest {      public static class Person {          private int per_id;          private String name;          private String sex;          private boolean state;          public Person(int per_id, String name, String sex, boolean state) {              this.per_id = per_id;              this.name = name;              this.sex = sex;              this.state = state;          }          @Override          public String toString() {              return "Person-->[per_id=" + per_id + ", name=" + name + ", sex="                      + sex + ", state=" + state + "]";          }      }      public static void main(String[] args) {          String json_str = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"state\":true}";          Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation()                  .create();          Person person = gson.fromJson(json_str, Person.class);          System.out.println("反序列化：" + person);          Person person1 = new Person(2, "layne", "man", true);          String json_str1 = gson.toJson(person1);          System.out.println("序列化："+json_str1);      }  }

public class SinceTest {      public static class Person {           @Since(2)          private int per_id;           @Since(2)          private String name;           @Since(2)          private String sex;           @Since(2)          private boolean state;          public Person(int per_id, String name, String sex, boolean state) {              this.per_id = per_id;              this.name = name;              this.sex = sex;              this.state = state;          }          @Override          public String toString() {              return "Person-->[per_id=" + per_id + ", name=" + name + ", sex="                      + sex + ", state=" + state + "]";          }      }      public static void main(String[] args) {          String json_str = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"state\":true}";          Gson gson = new GsonBuilder().setVersion(1)//版本为1                  .create();          Person person = gson.fromJson(json_str, Person.class);          System.out.println("反序列化v=1：" + person);          Person person1 = new Person(2, "layne", "man", true);          String json_str1 = gson.toJson(person1);          System.out.println("序列化v=1："+json_str1);          System.out.println("=================================");          Gson gson1 = new GsonBuilder().setVersion(2)//版本为2                  .create();          Person person2 = gson1.fromJson(json_str, Person.class);          System.out.println("反序列化v=2：" + person2);          Person person3 = new Person(2, "layne", "man", true);          String json_str2 = gson1.toJson(person3);          System.out.println("序列化v=2："+json_str2);          System.out.println("=================================");          Gson gson2 = new GsonBuilder().setVersion(3)//版本为3                  .create();          Person person4 = gson2.fromJson(json_str, Person.class);          System.out.println("反序列化v=3：" + person4);          Person person5 = new Person(2, "layne", "man", true);          String json_str3 = gson2.toJson(person5);          System.out.println("序列化v=3："+json_str3);      }  }

public class UtilTest {      public static class Person {          @Until(2)          private int per_id;          @Until(2)          private String name;          @Until(2)          private String sex;          @Until(2)          private boolean state;          public Person(int per_id, String name, String sex, boolean state) {              this.per_id = per_id;              this.name = name;              this.sex = sex;              this.state = state;          }          @Override          public String toString() {              return "Person-->[per_id=" + per_id + ", name=" + name + ", sex="                      + sex + ", state=" + state + "]";          }      }      public static void main(String[] args) {          String json_str = "{\"per_id\":1,\"name\":\"layne\",\"sex\":\"man\",\"state\":true}";          Gson gson = new GsonBuilder().setVersion(1)// 版本为1                  .create();          Person person = gson.fromJson(json_str, Person.class);          System.out.println("反序列化v=1：" + person);          Person person1 = new Person(2, "layne", "man", true);          String json_str1 = gson.toJson(person1);          System.out.println("序列化v=1：" + json_str1);          System.out.println("=================================");          Gson gson1 = new GsonBuilder().setVersion(2)// 版本为2                  .create();          Person person2 = gson1.fromJson(json_str, Person.class);          System.out.println("反序列化v=2：" + person2);          Person person3 = new Person(2, "layne", "man", true);          String json_str2 = gson1.toJson(person3);          System.out.println("序列化v=2：" + json_str2);          System.out.println("=================================");          Gson gson2 = new GsonBuilder().setVersion(3)// 版本为3                  .create();          Person person4 = gson2.fromJson(json_str, Person.class);          System.out.println("反序列化v=3：" + person4);          Person person5 = new Person(2, "layne", "man", true);          String json_str3 = gson2.toJson(person5);          System.out.println("序列化v=3：" + json_str3);      }  }

public class TypeAdapterTest {      public static class Person {          private int per_id;          private String name;          private String sex;          private boolean state;          public Person(int per_id, String name, String sex, boolean state) {              this.per_id = per_id;              this.name = name;              this.sex = sex;              this.state = state;          }          @Override          public String toString() {              return "Person-->[per_id=" + per_id + ", name=" + name + ", sex="                      + sex + ", state=" + state + "]";          }      }      public static void main(String[] args) throws Exception {          Gson gson = new Gson();          TypeAdapter<Person> personTypeAdapter = gson.getAdapter(Person.class);          Person person = new Person(1, "layne", "man", true);          String json_str = personTypeAdapter.toJson(person);          System.out.println("序列化结果:" + json_str);          Person person1 = personTypeAdapter.fromJson(json_str);          System.out.println("反序列化结果:" + person1);      }  }

Android框架-Google官方Gson解析

Android框架-Google官方Gson解析

Gson（又称Google Gson）是 Google 公司发布的一个开放源代码的 Java库，主要用途为序列化 Java 对象为 JSON 字符串，或反序列化 JSON 字符串成 Java 对象。

Gson 的实例化方式：

接下来介绍 Gson 的集中基本用法：

1、对象和 json 字符串的相互转换（先准备一个 Person 类）

测试代码：

运行结果：

2、集合和 json 字符串之间的转换：

接下来介绍抽象基类 JsonElement 的继承体系类：

运行结果：

Gson 库中的注解：有五种注解

1、首先着重的先说明重命名注解: SerializedName

替换关键字的 key：

运行结果：

替换冗余、难看的 key：

运行结果：

实例代码：

运行结果：

2、过滤注解：Expose

实例代码：

运行结果：

3、版本控制注解：Since、Util

实例代码：

运行结果：

实例代码：

运行结果：

运行结果：