Summary of the method of combining two arrays into one in Java implementation

This example describes the method of combining two arrays into one in Java. Share with you for your reference, as follows:

In Java, how to combine two strings [] into one?

It seems to be a very simple problem. But how to write the code efficiently and concisely is still worth thinking about. Here are four methods, please refer to the selection.

1、 Apache Commons

This is the simplest way. In Apache commons, there is an arrayutils The addall (object [], object []) method allows us to do it in one line:

String[] both = (String[]) ArrayUtils. addAll(first,second);

Others need to call the methods provided in the JDK and wrap them.

For convenience, I will define a tool method concat, which can combine two arrays:

static String[] concat(String[] first,String[] second) {}

For the sake of generality, I will use generics when possible, so that not only string [] can be used, but also other types of arrays can be used:

static
T[] concat(T[] first,T[] second) {}

Of course, if your JDK does not support generics or cannot be used, you can manually replace T with string.

2、 System arraycopy()

Use the following:

3、 Arrays copyOf()

In Java 6, there is a method, arrays Copyof() is a generic function. We can use it to write more general merging methods:

If you want to merge multiple, you can write this:

Use the following:

4、 Array newInstance

You can also use array Newinstance to generate an array:

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