通过将字符串（来自数组）分配为对象的参数之一，将其他参数设置为空，将字符串数组转换为对象列表

Question

I have a String array

adrs[] = {
    "BD Jules Ferry",
    "Rue de Republique",
    "Avenue de Julin"};

I have an Object named 'Address' (//getter setter omitted just for simplicity)

public class Address{

     adrsLine1 String;

     adrsLine2 String;

     adrsLine3 String;

     postalCode String;

}

I want to convert this adrs[] to List<<Address>> addrsList , by assigning each string in the array as adrsLine1 parameter of Address .

Once converted each address object in my addrsList will be like,

• addrsList.get(0) will have [BD Jules Ferry, null, null, null]
• addrsList.get(1) will have [Rue de Republique, null, null, null]
• addrsList.get(2) will have [Avenue de Julin, null, null, null]

I use Java 8, Currently, I use for loop to achieve this, is there any short cut or more efficient way available in Java 8?

Sample code:

private String[] AdrsArray = {"BD Jules Ferry", "Rue de Republique", "Avenue de Julin"};

List<Address> addrsList = new ArrayList<>();

for (String adrsLine : AdrsArray){
    Address address = new ReturnAddress();
    address.setAdrsLine1(adrsLine);
    addrsList.add(address);
} 

Output:

Address address = addrsList.get(0); 
address.getAdrsLine1() //should have "BD Jules Ferry"
address.getAdrsLine2() //should have null
address.getAdrsLine3() //should have null
address.getAdrsPostalCode() //should have null

Answer 1

You can use streams available in Java 8 to simplify your code as shown below.

List<Address> addrsList = Arrays.stream(adrs).map(adr -> {
    Address address = new ReturnAddress();
    address.setAdrsLine1(adr);
    return address;
}).collect(Collectors.toList());

Answer 2

List<Address> addressList = Arrays.stream(AdrsArray)
                                  .map(Address::new)
                                  .collect(Collectors.toList());

You have to add a constructor to Address class that accepts adrsLine1 .

public class Address{

     private String adrsLine1;

     private String adrsLine2;

     private String adrsLine3;

     private String postalCode;

     Address(String address1) {
       adrsLine1 = address1;
     }

}

Answer 3

You can use streams. I would recommend you to implement a constructor in class Address , such as

Address(String adrsLine1) {
  this.adrsLine1 = adrsLine1;
}

Then you can do it with this short code snippet:

List<Address> addrsList = Arrays.stream(adrs)
    .map(adr -> new Address(adr))
    .collect(Collectors.toCollection(ArrayList::new));

If you need a specific List type such as ArrayList , you should use Collectors.toCollection(ArrayList::new) , otherwise (if you can accept any list type) you can use just Collectors.toList() instead.