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java String[]和List<String>初始化的几种写法

关键词: java

java String[]和List初始化的几种写法

```
package com.example.demo;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Convert {

public static void demo01() {
        String[] str1 = new String[2];
        str1[0] = "1-0";
        str1[1] = "1-1";
        //
        String[] str2 = new String[]{"2-0", "2-1"};
        //
        String[] str3 = {"3-0", "3-1"};
        //
        System.out.println(Arrays.toString(str1));
        System.out.println(Arrays.toString(str2));
        System.out.println(Arrays.toString(str3));
    }

public static void demo02() {
        //元素个数已经被固定了，不能再添加元素
        List<String> list1 = Arrays.asList("x", "y");
        //
        List<String> list2 = new ArrayList<>(2);
        list2.add("x");
        list2.add("y");
        //元素个数没有被固定，还能再添加元素
        List<String> list3 = new ArrayList<>(Arrays.asList("x", "y"));
        list3.add("z");
        //
        List<String> list4 = new ArrayList<String>(2) {{
            add("a");
            add("b");
        }};
        //
        List<String> list5 = Stream.of("r", "g", "b").collect(Collectors.toList());
        //
        System.out.println(list1);
        System.out.println(list2);
        System.out.println(list3);
        System.out.println(list4);
        System.out.println(list5);
    }

public static void main(String[] args) {
        demo01();
        demo02();
    }

}
```

admin
2022-01-19 19:22:44
phantoscope

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java String[]和List<String>初始化的几种写法