Java 字符串比较方法。
Java String 类提供了不同的比较方法,包括
compareTo() 方法
此方法按字典顺序比较两个字符串。此方法返回: 如果当前字符串对象按字典顺序在参数字符串前面,则返回值为负整数。 如果当前字符串对象按字典顺序在参数后面,则返回值为正整数。 如果字符串相等,则返回值为 true。
示例
import java.lang.*;
public class StringDemo {
public static void main(String[] args) {
String str1 = "tutorials", str2 = "point";
// comparing str1 and str2
int retval = str1.compareTo(str2);
// prints the return value of the comparison
if (retval < 0) {
System.out.println("str1 is greater than str2");
}
else if (retval == 0) {
System.out.println("str1 is equal to str2");
} else {
System.out.println("str1 is less than str2");
}
}
}输出
str1 is less than str2
compareToIgnoreCase() 方法
此方法与 compareTo() 方法相同,它按字典顺序比较两个字符串,忽略大小写差异。
示例
import java.lang.*;
public class StringDemo {
public static void main(String[] args) {
String str1 = "tutorials", str2 = "TUTORIALS";
// comparing str1 and str2 with case ignored
int retval = str1.compareToIgnoreCase(str2);
// prints the return value of the comparison
if (retval > 0) {
System.out.println("str1 is greater than str2");
}
else if (retval == 0) {
System.out.println("str1 is equal to str2");
} else {
System.out.println("str1 is less than str2");
}
}
}输出
str1 is equal to str2
equals() 方法
此方法将该字符串与指定对象进行比较。当且仅当参数不是 null 并且它表示与此对象相同字符序列的字符串对象时,结果才为 true。
示例
import java.lang.*;
public class StringDemo {
public static void main(String[] args) {
String str1 = "sachin tendulkar";
String str2 = "amrood admin";
String str3 = "amrood admin";
// checking for equality
boolean retval1 = str2.equals(str1);
boolean retval2 = str2.equals(str3);
// prints the return value
System.out.println("str2 is equal to str1 = " + retval1);
System.out.println("str2 is equal to str3 = " + retval2);
}
}输出
str2 is equal to str1 = false str2 is equal to str3 = true
equalsIgnoreCase() 方法
此方法与 ignoreCase() 方法相同,但如果两个字符串长度相同,并且这两个字符串中的对应字符在忽略大小写的情况下相等,则认为这两个字符串是相等的。
示例
import java.lang.*;
public class StringDemo {
public static void main(String[] args) {
String str1 = "sachin tendulkar";
String str2 = "amrood admin";
String str3 = "AMROOD ADMIN";
// checking for equality with case ignored
boolean retval1 = str2.equalsIgnoreCase(str1);
boolean retval2 = str2.equalsIgnoreCase(str3);
// prints the return value
System.out.println("str2 is equal to str1 = " + retval1);
System.out.println("str2 is equal to str3 = " + retval2);
}
}输出
str2 is equal to str1 = false str2 is equal to str3 = true
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