java 去空格

1.trim() 方法用于删除字符串的头尾空白符。

public class Test {
    public static void main(String args[]) {
        String Str = new String(" hello word ");
        System.out.println( Str );

        System.out.print("删除空格 :" );
        System.out.println(Str.trim());
    }
}

2.replace(" ", "") 去掉所有空格

public class Test {
    public static void main(String args[]) {

        String str = " hello word ";
        String str2 = str.replaceAll(" ", "");
        System.out.println(str2); 
    }
}

3.deleteWhitespace 去掉所有空格

public class Test {
    public static void main(String args[]) {

        String str = " hello word ";
        String str1 = StringUtils.deleteWhitespace(str);
        
        System.out.println(str1);
    }
}

maven下载该jar org.apache.commons.lang.StringUtils

---

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.7</version>
</dependency>

源码：

  public static String deleteWhitespace(String str)
  {
    if (isEmpty(str))
      return str;

    int sz = str.length();
    char[] chs = new char[sz];
    int count = 0;
    for (int i = 0; i < sz; ++i)
      if (!(Character.isWhitespace(str.charAt(i))))
        chs[(count++)] = str.charAt(i);


    if (count == sz)
      return str;

    return new String(chs, 0, count);
  }