gson 使用Gson将Java对象转换为JSON

Gson是Google的一个开源项目，可以将Java对象转换成JSON，也可能将JSON转换成Java对象。 Gson里最重要的对象有2个Gson 和 GsonBuilder Gson有2个最基本的方法 1) toJson() – 转换java 对象到JSON 2) fromJson() – 转换JSON到java对象 下面是几个小例子 1. toJson() example Java 代码 收藏代码 1. class TestObjectToJson { 2. private int data1 = 100; 3. private String data2 = "hello"; 4. } 5. 6. TestObjectToJson obj = new TestObjectToJson(); 7. Gson gson = new Gson(); 8. String json = gson.toJson(obj); class TestObjectToJson { private int data1 = 100; private String data2 = "hello"; } TestObjectToJson obj = new TestObjectToJson(); Gson gson = new Gson(); String json = gson.toJson(obj); 会输出 {"data1":100,"data2":"hello"} 2. fromJson() example Java 代码 收藏代码 1. import com.google.gson.Gson; 2. 3. class TestJsonFromObject { 4. private int data1; 5. private String data2; 6. } 7. 8. String json = "{'data1':100,'data2':'hello'}"; 9. Gson gson = new Gson(); 10. TestJsonFromObject obj = gson.fromJson(json, TestJsonFromObject.class); import com.google.gson.Gson; class TestJsonFromObject { private int data1; private String data2; } String json = "{'data1':100,'data2':'hello'}"; Gson gson = new Gson(); TestJsonFromObject obj = gson.fromJson(json, TestJsonFromObject.class); 3. 将Java对象的属性转换成指定的JSON名字 Java 代码 收藏代码 1. import com.google.gson.FieldNamingPolicy; 2. import com.google.gson.Gson; 3. import com.google.gson.GsonBuilder; 4. import com.google.gson.annotations.SerializedName; 5. 6. public class TestGson { 7. 8. @SerializedName("first_field") 9. private String field1; 10. 11. private String secondField; 12. 13. public TestGson(String param1, String param2) { 14. field1 = param1; 15. secondField = param2; 16. } 17. } 18. 19. TestGson obj = new TestGson("aaaa", "bbbbb"); 20. Gson gson = new GsonBuilder().setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE).create(); 21. gson.toJson(obj); import com.google.gson.FieldNamingPolicy; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.annotations.SerializedName; public class TestGson { @SerializedName("first_field") private String field1; private String secondField; public TestGson(String param1, String param2) { field1 = param1; secondField = param2; } } TestGson obj = new TestGson("aaaa", "bbbbb"); Gson gson = new GsonBuilder().setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE).create(); gson.toJson(obj); 输出结果 {"first_field":"aaaa","SecondField":"bbbbb"}