Fastjson首字母大小写问题
最近由于项目里用到了多个json类库，fastjson,org.json,jackson都有用到，最终把json类库统一成了API最为简单的Fastjson。
Fastjson替换org.json之后导致部分功能不可用，最终确定为fastjson的默认首字母小写机制造成的。
maven依赖
<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.75</version></dependency>
测试代码
// 省略get set
public class Student {private String ID;private String NAME;private String ADDREDD;}
测试代码
import com.alibaba.fastjson.JSON;public class FastjsonTest {public static void main(String[] args) {Student student = new Student();student.setID("123");student.setNAME("zhangsan");student.setADDREDD("shanghai");String s = JSON.toJSONString(student);System.out.println(s);}}
{"aDDREDD":"shanghai","iD":"123","nAME":"zhangsan"}
解决办法
patibleWithJavaBean设置为true
patibleWithJavaBean = true;
也可以通过设置jvm参数。
2.@JSONField注解
public class Student {@JSONField(name = "ID")private String ID;@JSONField(name="NAMW")private String NAME;@JSONField(name = "ADDRESS")private String ADDREDD;}
{"ADDRESS":"shanghai","ID":"123","NAMW":"zhangsan"}
问题分析
通过查看Fastjson源码可知，Fatjson在序列化对象时，会判断compatibleWithJavaBean，如果为fals则将首字母小写，compatibleWithJavaBean默认值为false.
ublic class TypeUtils {private static final Pattern NUMBER_WITH_TRAILING_ZEROS_PATTERN = pile("\\.0*$");public static boolean compatibleWithJavaBean = false;public static boolean compatibleWithFieldName = false;...}
...if (Character.isUpperCase(c2)) {if (compatibleWithJavaBean) {propertyName = decapitalize(methodName.substring(2));} else {propertyName = Character.toLowerCase(methodName.charAt(2)) + methodName.substring(3);}propertyName = getPropertyNameByCompatibleFieldName(fieldCacheMap, methodName, propertyName, 2);...
参考资料
/alibaba/fastjson/issues/373
