String的Compareto方法将两个字符串进行了比较。
两个字符串都转换为Unicode值，然后进行比较。

如果我们调用str1.compareto(str2)

然后，如果str1大于str2 返回正数：
0：str1等于str2
负数：str1小于str2

Java String Compareto示例

package org.igi.theitroad;
 
public class StringCompareToExampleMain {
 public static void main(String[] args) {
  String str1="theitroad";
     String str2="hello";
    String str3="world";
    String str4="theitroad";
    String str5="theitroad";
    
    System.out.println("comparing theitroad with hello : "+str1.compareTo(str2));
    System.out.println("comparing hello with world : "+str2.compareTo(str3));
  System.out.println("comparing theitroad with theitroad : "+str1.compareTo(str4));
  System.out.println("comparing theitroad with theitroad : "+str1.compareTo(str5));
 }
 
}

运行上面的程序时，我们将得到以下输出：

comparing theitroad with hello : 2
comparing hello with world : -15
comparing theitroad with theitroad : 0
comparing theitroad with theitroad : 32