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 class TestObjectToJson { private int data1 = 100; private String data2 = "hello"; } TestObjectToJson obj = new TestObjectToJson(); Gson gson = new Gson(); 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 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); 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 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); 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"}