从java中的字符串数组中删除空值 [英] Remove Null Value from String array in java

问题描述

java中如何去除String数组中的空值?

How to remove null value from String array in java?

String[] firstArray = {"test1","","test2","test4",""};

我需要像这样没有空(空)值的firstArray"

I need the "firstArray" without null ( empty) values like this

String[] firstArray = {"test1","test2","test4"};

推荐答案

如果你想避免 fencepost 错误并避免移动和删除数组中的项目，这里有一个使用 List 的有点冗长的解决方案:

If you want to avoid fencepost errors and avoid moving and deleting items in an array, here is a somewhat verbose solution that uses List:

import java.util.ArrayList;
import java.util.List;

public class RemoveNullValue {
  public static void main( String args[] ) {
    String[] firstArray = {"test1", "", "test2", "test4", "", null};

    List<String> list = new ArrayList<String>();

    for(String s : firstArray) {
       if(s != null && s.length() > 0) {
          list.add(s);
       }
    }

    firstArray = list.toArray(new String[list.size()]);
  }
}

添加了 null 以显示空 String 实例 ("") 和 null 之间的区别.

Added null to show the difference between an empty String instance ("") and null.

由于这个答案大约有 4.5 年的历史，所以我添加了一个 Java 8 示例:

Since this answer is around 4.5 years old, I'm adding a Java 8 example:

import java.util.Arrays;
import java.util.stream.Collectors;

public class RemoveNullValue {
    public static void main( String args[] ) {
        String[] firstArray = {"test1", "", "test2", "test4", "", null};

        firstArray = Arrays.stream(firstArray)
                     .filter(s -> (s != null && s.length() > 0))
                     .toArray(String[]::new);    

    }
}

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