我需要在Java中连接两个字符串数组。

void f(String[] first, String[] second) {
    String[] both = ???
}

哪种方法最简单?


当前回答

public int[] mergeArrays(int [] a, int [] b) {
    int [] merged = new int[a.length + b.length];
    int i = 0, k = 0, l = a.length;
    int j = a.length > b.length ? a.length : b.length;
    while(i < j) {
        if(k < a.length) {
            merged[k] = a[k];
            k++;
        }
        if((l - a.length) < b.length) {
            merged[l] = b[l - a.length];
            l++;
        }
        i++;
    }
    return merged;
}

其他回答

public String[] concat(String[]... arrays)
{
    int length = 0;
    for (String[] array : arrays) {
        length += array.length;
    }
    String[] result = new String[length];
    int destPos = 0;
    for (String[] array : arrays) {
        System.arraycopy(array, 0, result, destPos, array.length);
        destPos += array.length;
    }
    return result;
}
ArrayList<String> both = new ArrayList(Arrays.asList(first));
both.addAll(Arrays.asList(second));

both.toArray(new String[0]);

使用Java 8+流,您可以编写以下函数:

private static String[] concatArrays(final String[]... arrays) {
    return Arrays.stream(arrays)
         .flatMap(Arrays::stream)
         .toArray(String[]::new);
}

一个100%旧的java和没有System.arraycopy的解决方案(例如GWT客户端中不可用):

static String[] concat(String[]... arrays) {
    int length = 0;
    for (String[] array : arrays) {
        length += array.length;
    }
    String[] result = new String[length];
    int pos = 0;
    for (String[] array : arrays) {
        for (String element : array) {
            result[pos] = element;
            pos++;
        }
    }
    return result;
}

以下是对我有用的:

String[] data=null;
String[] data2=null;
ArrayList<String> data1 = new ArrayList<String>();
for(int i=0; i<2;i++) {
   data2 = input.readLine().split(",");
   data1.addAll(Arrays.asList(data2));
   data= data1.toArray(new String[data1.size()]);
   }