技術標籤：java字串字串javajson

java反射實現物件轉json字串

這裡只作為反射學習的一個案例，當然有好多json工具可以實現json字串和物件的轉換。

定義倆個函式，一個是不包含物件的物件裝json字串，一個是包含物件的物件轉json字串，主要思路就是利用反射來獲取物件的屬性名和屬性值，然後拼接成json字串

import java.lang.reflect.Field;

//java物件轉json物件字串
public class test {
	
	//所有屬性為基本型別或String
	public static String transformString(Object object)
 
 throws Exception {
		String res="{";
		Class<?> c=object.getClass();
		Field[] fields=c.getDeclaredFields();
		for (Field field : fields) {
			field.setAccessible(true);
			res+=('"'+field.getName()+'"'+":"+'"'+field.get(object).toString()+'"');
			if(field!=
 
fields[fields.length-1]) {
				res+=",";
			}
		}
		res+="}";
		return res;
	}
	
	//包含物件的json
	public static String newTransformString(Object object) throws Exception {
		String res="{";
		Class<?> c=object.getClass();
		Field[] fields=c.getDeclaredFields();
		for (
 
Field field : fields) {
			field.setAccessible(true);
			res+=('"'+field.getName()+'"'+":");
			if(field.getType().isPrimitive()||field.get(object) instanceof String){
				res+=('"'+field.get(object).toString()+'"');
			}else {
				res+=newTransformString(field.get(object));
			}
			if(field!=fields[fields.length-1]) {
				res+=",";
			}
		}
		res+="}";
		return res;
	}
	
	public static void main(String[] args) throws Exception {
		Student student=new Student();
		student.setSno(10001);
		student.setName("張三");
		student.setMajor("軟體工程");
		
		String jsonString=transformString(student);
		System.out.println(jsonString);	
		
		Person person=new Person();
		person.setName("John Doe");
		person.setAge(18);
		person.setAddress(new Address("china",10000));
		
		String newJsonString=newTransformString(person);
		System.out.println(newJsonString);
	}
}