Question

如何在java里java字符串数组合并成一个数组？

Answer 1

java里java字符串数组合并成一个数组方法如下：

//方法一 Arrays类

String[] a = {"A","B","C"};

String[] b = {"D","E"};

// List<String> list = Arrays.asList(a);  --OK

// List<String> list = Arrays.asList("A","B","C"); --OK

// list.add("F"); --UnsupportedOperationException

// list.remove("A"); --UnsupportedOperationException

// list.set(1,"javaee");--OK (因为是把数组转为集合，其本质还是数组，数组长度固定不变，但内容可以改变)

// 结论：虽然可以把数组转为集合，但是集合长度不能改变

List list = new ArrayList(Arrays.asList(a));

list.addAll(Arrays.asList(b));

String[] str = new String[list.size()];

list.toArray(str); 

for(int x=0;x<str.length;x++){

System.out.print(str[x] + " ");

}

//方法二 循环遍历

// 两个数组合并

String[] str1 = {"Hello","world","java"};

String[] str2 = {"Veriable","syntax","interator"};

String[] newStr = new String[str1.length+str2.length];

//newStr = str1;数组是引用类型

for(int x=0;x<str1.length;x++){

newStr[x] = str1[x];

}   

for(int y=0;y<str2.length;y++){

newStr[str1.length+y]=str2[y];

}

for(int y=0;y<newStr.length;y++){

System.out.println(newStr[y] + " ");

  }

// 方法三

String[] str1 = {"Hello","world","java"};

String[] str2 = {"Veriable","syntax","interator"};

int str1Length = str1.length;

int str2length = str2.length;

str1 = Arrays.copyOf(str1, str1Length+str2length);//数组扩容

System.arraycopy(str2, 0, str1, str1Length, str2length);

System.out.println(Arrays.toString(str1));