Java String compareToIgnoreCase()用法及代码示例

字符串 compareToIgnoreCase() 方法

compareToIgnoreCase() 是 Java 中的 String 方法，用于通过忽略大小写的敏感性来比较两个字符串。

如果两个字符串相等(不考虑区分大小写)——它返回 0，否则根据第一个不同的字符差异返回小于 0 或大于 0 的值。

用法:

    int string1.compareToIgnoreCase(string2);

这里，string1和string2是要比较的字符串，它返回一个 0、小于 0 或大于 0 的整数值。

例：

    Input:
    str1 = "Hello world!"
    str2 = "Hello world!"

    Output:
    0

    Input:
    str1 = "Hello world!"
    str2 = "HELLO WORLD!"

    Output:
    0

    Input:
    str1 = "Hello world!"
    str2 = "Hi guys!!!"

    Output:
    -4

使用 String.compareToIgnoreCase() 方法比较字符串的 Java 代码

public class Main
{
    public static void main(String[] args) {
        String str1 = "Hello world!";
        String str2 = "Hello world!";
        String str3 = "HELLO WORLD!";
        
        System.out.println("str1 and str2 = " + str1.compareToIgnoreCase(str2));
        System.out.println("str1 and str3 = " + str1.compareToIgnoreCase(str3));
        System.out.println("str2 and str3 = " + str2.compareToIgnoreCase(str3));
        
        //checking with the condition
        if(str1.compareToIgnoreCase(str2)==0){
            System.out.println("str1 is equal to str2");
        }
        else{
            System.out.println("str1 is not equal to str2");
        }

        if(str1.compareToIgnoreCase(str3)==0){
            System.out.println("str1 is equal to str3");
        }
        else{
            System.out.println("str1 is not equal to str3");
        }        
        
        if(str2.compareToIgnoreCase(str3)==0){
            System.out.println("str2 is equal to str3");
        }
        else{
            System.out.println("str2 is not equal to str3");
        }        
        
    }
}

输出

str1.compareToIgnoreCase(str2) = 0
str1.compareToIgnoreCase(str3) = 0
str2.compareToIgnoreCase(str3) = 0
str1 is equal to str2
str1 is equal to str3
str2 is equal to str3

public class Main
{
    public static void main(String[] args) {
        String str1 = "Hello world!";
        String str2 = "Hi guys!!!";
        
        if(str1.compareToIgnoreCase(str2)==0){
            System.out.println("str1 is equal to str2");
        }
        else{
            System.out.println("str1 is not equal to str2");
        }        
    }
}

输出

str1 is not equal to str2