使用gson将嵌套的JSON转换为嵌套的Java对象TypeAdapter

我正尝试使用google gson TypeAdapter将嵌套的JSON转换为嵌套的Java对象，并为每个类实现了TypeAdapter。但我不想在单个适配器类中编写完整的read（）方法逻辑。我已经通过网络提到了几个问题和blog例子。但是完整的读取逻辑是单独的。使用gson将嵌套的JSON转换为嵌套的Java对象TypeAdapter

对于小型嵌套对象，它可以在单个Adapter中使用逻辑，但对于大对象（每个类中有超过10-15个字段），这并不好。

[更新]

例如JSON键看起来相同的类属性，但在实际我会得到输入为hyphen-separated-small-case键，而不是Camel case键。所以我的json和java类属性名称将不会相同，因此我必须编写我的定制逻辑进行映射。

E.g. 样品的Json输入：

{ 
    "id": 1, 
    "name": "Alex", 
    "emailId": "[email protected]", 
    "address": { 
    "address": "21ST & FAIRVIEW AVE", 
    "district": "district", 
    "city": "EATON", 
    "region": "PA", 
    "postalCode": "18044", 
    "country": "US" 
    } 
}

而Java Bean是如下：

//Employee object class 
public class Employee { 

    private int id; 
    private String name; 
    private String emailId; 
    private Address address; 
    .. 
} 

//Address object class 
public class Address { 

    private String address; 
    private String district; 
    private String city; 
    private String region; 
    private String postalCode; 
    private String country; 
    .. 
}

我想有两个不同的适配器和在读集成多个适配器（）方法。

public class EmployeeAdapter extends TypeAdapter<Employee> { 
    @Override 
    public void write(JsonWriter out, Employee employee) throws IOException { 
    // 
    } 

    @Override 
    public Employee read(JsonReader jsonReader) throws IOException { 
    //read logic for employee class using AddressAdapter for address json 
    } 
} 

public class AddressAdapter extends TypeAdapter<Address> { 
    @Override 
    public void write(JsonWriter out, Address address) throws IOException { 
    // 
    } 

    @Override 
    public Address read(JsonReader jsonReader) throws IOException { 
    //read logic for Address class 
    } 
}

如何在EmployeeAdapter中使用AddressAdapter？

来源

2017-03-07 GovindS

您是否尝试过使用阅读器的默认实现？或者你有特定的理由来编写自己的适配器？ –

这与杰克逊有什么关系？请删除标签 –

它看起来像你只需要POJO映射，而类型适配器真的是一个矫枉过正的地方：'最终员工雇员= gson.fromJson（...，Employee.class）'似乎是完整的。 –

您可以创建封装在EmployeeAdapter中的AddressAdapter的新实例。请通过以下示例。

public class EmployeeAdapter extends TypeAdapter<Employee> { 
    //private instance of address adapter 
    private AddressAdapter addressAdapter = new AddressAdapter(); 

    @Override 
    public void write(JsonWriter out, Employee employee) throws IOException { 
     //TODO: do your stuff to Employee class 

     //manually do it to Address class 
     addressAdapter.write(out, employee.getAddress()); 
    } 

    @Override 
    public Employee read(JsonReader jsonReader) throws IOException { 
     //your new instance of employee 
     Employee employee = new Employee(); 

     //TODO: read logic for employee class using AddressAdapter for address json 

     //read from Address class 
     Address address = addressAdapter.read(jsonReader);//you may need only portion of address available, simply grab that string as same as other properties if needed 
     employee.setAddress(address); 
    } 
}

来源

2017-03-07 09:53:22

这没关系。但是在AddressAdapter中不会使用'TypeAdapter

'。 – GovindS

我有同样的问题，并找到适合我的解决方案。

您可以在Gson对象及其方法getAdapter(Class<T> type)的帮助下获得新的TypeAdapter<T>实例。

所以您提供的例子应该是这样的：

Java组件：

//Employee object class 
@JsonAdapter(EmployeeAdapter.class) 
public class Employee { 

    private int id; 
    private String name; 
    private String emailId; 
    private Address address; 
    .. 
} 

//Address object class 
@JsonAdapter(AddressAdapter.class) 
public class Address { 

    private String address; 
    private String district; 
    private String city; 
    private String region; 
    private String postalCode; 
    private String country; 
    .. 
}

型适配器：

public class EmployeeAdapter extends TypeAdapter<Employee> { 
    @Override 
    public void write(JsonWriter out, Employee employee) throws IOException { 
    // 
    } 

    @Override 
    public Employee read(JsonReader jsonReader) throws IOException { 
    Employee employee = new Employee(); 

    jsonReader.beginObject(); 
    //read your Employee fields 

    TypeAdapter<Address> addressAdapter = new Gson().getAdapter(Address.class); 
    employee.setAddress(addressAdapter.read(jsonReader); 

    return employee; 
    } 
} 

public class AddressAdapter extends TypeAdapter<Address> { 
    @Override 
    public void write(JsonWriter out, Address address) throws IOException { 
    // 
    } 

    @Override 
    public Address read(JsonReader jsonReader) throws IOException { 
    Address address = new Address(); 
    //read your Address fields 
    return address; 
    } 
}

有了这个解决方案，您有一个松耦合代码的好处，因为Beans JsonAdapter注释中唯一的依赖。
Addtional将每个Bean的读/写逻辑分配给它自己的TypeAdapter。

来源

2017-11-21 08:02:09 Dennis

使用gson将嵌套的JSON转换为嵌套的Java对象TypeAdapter

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