fastjson解析json时报错 class not has default constructor
发布时间:2020-12-16 18:50:41 所属栏目:百科 来源:网络整理
导读:在序列化用alibaba的json包把对象进行序列化的时候,总是报错 Exception in thread "main" com .alibaba .fastjson .JSONException : default constructor not found. class com .mex .test .redis .Person Person类 public class Person { private String n
在序列化用alibaba的json包把对象进行序列化的时候,总是报错 Exception in thread "main" com.alibaba.fastjson.JSONException: default constructor not found. class com.mex.test.redis.Person
Person类 public class Person {
private String name;
private int age;
public Person(String name,int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public void setAge(int age) {
this.age = age;
}
}
User类 public class User {
private String id;
private List<Person> users = new ArrayList<Person>();
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public List<Person> getUsers() {
return users;
}
public void setUsers(List<Person> users) {
this.users = users;
}
}
测试类 public class SerializationTest {
public static void main(String[] args) {
User user = new User();
user.setId("1001");
Person p1 = new Person("xiaoming",23);
Person p2 = new Person("jack",34);
ArrayList<Person> pList = Lists.newArrayList();
pList.add(p1);
pList.add(p2);
user.setUsers(pList);
// 序列化
String s = JSON.toJSONString(user);
System.out.println(s);
User user1 = JSON.parSEObject(s,User.class);
System.out.println(user1);
}
}
查找了半天的资料,fastJson在反序列化的时候需要调用对象的默认构造方法,如果该对象之中还包含其他的对象,那么都需要创建默认的无参构造方法。 解决方案:将User的默认无参构造和Person的默认无参构造补充到类中,即可。 public User() {
}
public Person() {
}
打印出来的信息为: {"id":"1001","users":[{"age":23,"name":"xiaoming"},{"age":34,"name":"jack"}]}
com.mex.test.redis.User@15f550a
Process finished with exit code 0
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