如何从ArrayList获取值<String[]>

Question

How to get or print String from ArrayList<String[]> ?

ArrayList<String[]> arrayList = new ArrayList<>();
arrayList.add(new String[]{"A1","A1","A3"});
arrayList.add(new String[]{"B1","B1","B3"});
arrayList.add(new String[]{"C1","C1","C3"});

System.out.println("*** 1 ***");
System.out.println(arrayList);

System.out.println("*** 2 ***");
for (int i = 0; i < arrayList.size(); i++) {
    System.out.println((String[])arrayList.get(i));
}

System.out.println("*** 3 ***");
for (int i = 0; i < arrayList.size(); i++) {
    System.out.println(arrayList.get(i).toString());
}

System.out.println("*** 4 ***");
for (int i = 0; i < arrayList.size(); i++) {
    String[] strings = arrayList.get(i);
    System.out.println(strings);
}

output:

*** 1 ***
[[Ljava.lang.String;@2a85f3d6, [Ljava.lang.String;@404b7c69, [Ljava.lang.String;@1bd4f279]

*** 2 ***
[Ljava.lang.String;@2a85f3d6
[Ljava.lang.String;@404b7c69
[Ljava.lang.String;@1bd4f279
*** 3 ***
[Ljava.lang.String;@2a85f3d6
[Ljava.lang.String;@404b7c69
[Ljava.lang.String;@1bd4f279
*** 4 ***
[Ljava.lang.String;@2a85f3d6
[Ljava.lang.String;@404b7c69
[Ljava.lang.String;@1bd4f279

Answer 1

Sadly, java's default toString() for arrays is useless. You must use the utility method Arrays.toString() . This will work:

for (String[] strings : arrayList)
    System.out.println(Arrays.toString(strings));

Answer 2

In Java, each object has toString() method, the default is displaying the class name representation, then adding @ and then the hashcode.

strings is an array of String s. You should use Arrays#toString() , which is implemented this way (I advise you to go through it to better understand what's going on):

3860     public static String toString(int[] a) { {
3861        if (a == null)
3862            return "null";
3863        int iMax = a.length - 1;
3864        if (iMax == -1)
3865            return "[]";
3866
3867        StringBuilder b = new StringBuilder();
3868        b.append('[');
3869        for (int i = 0; ; i++) {
3870            b.append(a[i]);
3871            if (i == iMax)
3872                return b.append(']').toString();
3873            b.append(", ");
3874        }
3875    }

Or, you can loop on it and manually print the items:

for(String str: strings) {
    System.out.println(str + " ");
}

Answer 3

Try to modify this :

**@Override
public String toString() {
    return "abc [name=" + name + ", stage=" + stage
            + ", messageCode=" + messageCode + ", title=" + title
            + ", description=" + description + ", expiryTimeLeft="
            + expiryTimeLeft + ", holdLimit=" + holdLimit + ", points="
            + points];
}