Java工具类(字符串)

妖狐艹你老母 2024-04-20 11:33 74阅读 0赞

## 无视类型/是list还是Array直接进行字符拼接 ##

lang3

StringUtils.join(List.of(1, 2, 3), ","
    // 1,2,3

## 切分 ##

按照某个字符串进行切分

String str2 = "abc,def";
    String[] split = str.split(",");

通过正则表达式切分

String str2 = "abc,def,gch";
    String[] split1 = str2.split(",|a");

限制切分数量的切分

String str2 = "abc,de,f";
    String[] split = str.split(",", 2);

合并空格并强制切分

" a b  c ".strip().split("\\s+")

#### 截取 ####

通过开始结尾两个分隔符获取有效信息

String message = StringUtils.substringBetween("name: lix, age: 12,", "name: ", ",");
    String message2 = StringUtils.substringBetween("name1: lix, age: 12,", "name: ", ",");

获取多个切分点

String[] strings = StringUtils.substringsBetween("abcd abcd", "a", "d");

## 替换前N个字符 ##

StringUtils.replace("1111122222", "11", "ab", 2)
    // abab122222

![在这里插入图片描述][b2b38bbf1e7848ec9e10784e682babc7.png]

## 拼接 ##

String join = StringUtils.join(List.of(1, 2, 3), ",");
    //1,2,3
    String join = StringUtils.join(List.of(1, 2, 3), "");
    //123

流式合并

List<Integer> list = List.of(1, 2, 3);
     String collect = list.stream().map(Object::toString).collect(Collectors.joining(","));
     //1,2,3

## 比较 ##

忽略大小写比较字符串

boolean abc2 = "abc".equalsIgnoreCase("Abc");

boolean b = StringUtils.equalsIgnoreCase("abc", "ABC");

#### 去掉多余字符 ####

切掉前后的【】等字符

StringUtils.strip("[abc, def, gch]", "[]");
    // abc, def, gch

切除空格

String strip = "  abc  ".strip();

StringUtils.trim(" abc ");
    // abc

合并所有空格并只将空格只保留一个字符

String s = "a b c".replaceAll("\\s+", " ");

逗号分隔

String[] split = "a, b, c ".strip().split("\\s*,\\s*");

删除最后一个字符(假如匹配)

String s1 = StringUtils.removeEnd("abcdavbabc", "abc");
    String s1 = StringUtils.removeEnd("abcdavbabc", "ab"); // 啥都不做

### 空白和NULL判断 ###

StringUtils.defaultIfBlank(null, "null1");
    StringUtils.defaultIfBlank("", "null2");
    StringUtils.defaultIfBlank(" ", "null3");
    // null1
    // null2
    // null3

字符串列表中null和空白替换为特定字符

List<String> stringList = new ArrayList<>(List.of("a", "b", "c", ""));
    stringList.add(null);
    stringList.replaceAll(x -> StringUtils.defaultIfBlank(x, ""));

比较两个字符串是否相等

boolean abc2 = Objects.equals("abc", null);

判断是否为null|空|blank lang3

String s = StringUtils.isBlank(null);
    // true

删除空白字符

List<String> stringList = new ArrayList<>(List.of("a", "b", "c", ""));
    stringList.removeIf(StringUtils::isBlank);
    // a, b, c

全角转半角

public static String toHalfCharacter(String input) {
        
            if (input == null) {
        
                return null;
            }
            char[] c = input.toCharArray();
            for (int i = 0; i < c.length; i++) {
        
                if (c[i] == 12288) {
        
                    c[i] = (char) 32;
                    continue;
                }
                if (c[i] > 65280 && c[i] < 65375)
                    c[i] = (char) (c[i] - 65248);
            }
            return new String(c);

## 其他操作 ##

字符串翻转

String s1 = new StringBuilder("abc").reverse().toString();
    // cba

String abc = StringUtils.reverse("abc");
    //cba

通过boolen进行映射

String s = BooleanUtils.toString(true, "true", "false");

## 展示所有类型字符串 ##

需要org.junit.platform.commons.util.StringUtils.nullSafeToString

打印一切可以打印的字符、列表、空指针、类

System.out.println(org.junit.platform.commons.util.StringUtils.nullSafeToString(new int[]{1, 2, 4}));
            System.out.println(org.junit.platform.commons.util.StringUtils.nullSafeToString(null));
            System.out.println(org.junit.platform.commons.util.StringUtils.nullSafeToString(Collections.EMPTY_LIST));
    	// null
    	// []
    	// [1, 2, 3, 4]

[b2b38bbf1e7848ec9e10784e682babc7.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/08/c3588e00fc494b7ea564093067d045ce.png