convert list<map<string,object>> to object of a POJO class

Question

I have a List of HashMap objects in which hashMap object contains property name as key and value of property as value list>. How to convert each of these HashMap object into an object of my POJO class.??

Answer 1

Here is how you can do it using reflection:

Pojo class:

public class MyPojo {
    private String text;
    private Integer number;

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public Integer getNumber() {
        return number;
    }

    public void setNumber(Integer number) {
        this.number = number;
    }
}

Populate instances of your pojo using reflection;

final List<Map<String, Object>> objects = new ArrayList<Map<String, Object>>();
objects.add(new HashMap<String, Object>());
objects.get(0).put("text", "This is my text value.");
objects.get(0).put("number", 10);
objects.add(new HashMap<String, Object>());
objects.get(1).put("text", "This is my second text value.");
objects.get(1).put("number", 20);

ArrayList<MyPojo> pojos = new ArrayList<MyPojo>();

for (Map<String, Object> objectMap : objects) {
    MyPojo pojo = new MyPojo();
    for (Entry<String, Object> property : objectMap.entrySet()) {
        Method setter = MyPojo.class.getMethod("set" + property.getKey().substring(0, 1).toUpperCase()
                + property.getKey().substring(1), property.getValue().getClass());
        setter.invoke(pojo, property.getValue());
    }
    pojos.add(pojo);
}

for (MyPojo pojo : pojos) {
    System.out.println(pojo.getText() + " " + pojo.getNumber());
}

Output:

This is my text value. 10

This is my second text value. 20