How to use Jackson ObjectMapper to convert to Pojo for multiple data

Question

I would like to convert the following string/ JSONObject to POJO,

{"list":["\r\n{\r\n\"id\":\"1\",\r\n\"protocol\":\"udp\",\r\n\"srcPorts= \":\"3000-4000    \",\r\n\"destPorts\":\"1790-2000\"\r\n}","\r\n{\r\n\"id\":\"2\",\r\n    \"protocol\":\"tcp\",\r\n\"srcPorts\":\"3000-4000\",\r\n\"destPorts\":\"1790-2000    \"\r\n}"],"user":"\r\n{\r\n\"name\":\"John\",\r\n\"address\":\"x.x.x.x\",\r\n\"email     \":\"john@p.com\"\r\n}"}

How do I convert to Pojo using Jackson ObjectMapper. The 2 Pojo classes are as follows.

The user part in the string above should map to the java file - User.java

public class User 
{
    private String name;

    private String address;

    private String email;

    public String getName()
    {
        return name;
    }

    public void setName(String name) 
    {
        this.name = name;
    }

    public String getAddress() 
    {
        return address;
    }

    public void setaddress(String Address) 
    {
        this.address = address;
    }

    public String getEmail()
    {
        return email;
    }

    public void setEmail(String email)
    {
        this.email = email;
    }   
}

The List part in the string above should map to the java file - TestCase.java

public class TestCase 
{
    private String id;
    private String protocol;
    private String srcPorts;
    private String destPorts;

    public String getProtocol()
    {
        return protocol;
    }

    public void setProtocol(String protocol) 
    {
        this.protocol = protocol;
    }

    public String getSrcPorts() 
    {
        return srcPorts;
    }

    public void setSrcPorts(String srcPorts) 
    {
        this.srcPorts = srcPorts;
    }

    public String getDestPorts() 
    {
        return destPorts;
    }

    public void setDestPorts(String destPorts) 
    {
        this.destPorts = destPorts;
    }

    public String getID() 
    {
        return id;
    }

    public void setID(String id) 
    {
        this.id = id;
    }       
}

score 1 · Answer 1 · answered Mar 27 '14 at 07:31

1

Following code should help.

class ParseJson{

private User user;
private TestCase testCase;

//getter and setter methods
}
//and then call objectMapper - 
String jsonString = "";//Json input
ObjectMapper mapper = new ObjectMapper();
ParseJson parsedJson = mapper.readValue(jsonString, ParseJson.class);

User user = parsedJson.getUser();
TestCase testCase = parsedJson.getTestCase();

answered Mar 27 '14 at 07:31

hellboy

2,222
1
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Considering that the POJOs in the OP's code are neither Serializable, nor do they have Jackson annotations, is that a good idea? Sounds like a very good way to make the system sensitive to the slightest code change... – thkala Mar 27 '14 at 07:41
You don't need either if the intention is to just parse json into java object and not looking for any kind of manipulation. The default behavior will take care of conversion without any issues. The above approach will keep the code clean and readable. – hellboy Mar 27 '14 at 08:05

score 0 · Answer 2 · edited May 23 '17 at 10:31

0

Since your JSON object does not contain any type information, the best approach would be to use a custom deserializer class for Jackson, at least for the outer class. Alternatively, you can try annotating your POJO classes with Jackson annotations, and hope that the Right Thing happens.

In any case, you will have to make Jackson aware of your context by calling one of the ObjectMapper.readValue() methods with the proper class type argument, so that Jackson will know what it is that is being deserialized.

edited May 23 '17 at 10:31

Community

1
1

answered Mar 27 '14 at 07:24

thkala

84,049
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Thanks. And what is type information and how would adding the type information change the conversion to POJO. What are the Jackson annotations that you are referring to? – Harish Mar 27 '14 at 07:29
@Harish: as it is, your JSON object could be perfectly mapped to core Java classes, such as `ArrayList` and `LinkedHashMap`. By default Jackson knows nothing about your POJOs. It is possible to get Jackson to add type information (i.e. the class name) to your JSON, but that would add fields to the JSON object. It is generally safer to just use annotations or a custom deserializer, along with calling `readValue()` with the right class type argument. – thkala Mar 27 '14 at 07:36

How to use Jackson ObjectMapper to convert to Pojo for multiple data

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