Java RuleBasedCollator compare()用法及代码示例

java.text.RuleBasedCollator类的compare()方法用于比较两个对象的强度，并且根据结果将返回0，正值和负值作为输出。

用法:

public int compare(Object o1, Object o2)

参数：此方法需要两个对象之间进行比较。

返回值：如果第一个对象等于，小于或小于另一个对象，则它将分别返回零，正值和负值。

异常：如果参数之一为null，则此方法引发NullPointerException。

下面是说明compare()方法的示例：

范例1：

// Java program to demonstrate 
// compare() method 
  
import java.text.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // Creating and initializing 
            // RuleBasedCollator Object 
            RuleBasedCollator col 
                = new RuleBasedCollator("< a< b< c< d"); 
  
            // Creating an initializing 
            // object for comparison 
            Object obj1 = "ab"; 
  
            // Creating an initializing 
            // Object for comparison 
            Object obj2 = "Ab"; 
  
            // compare both object 
            // using compare() mehtod 
            int i 
                = col.compare((String)obj1, 
                              (String)obj2); 
  
            // display result 
            if (i < 0) 
                System.out.println("ab is less than Ab"); 
            else if (i > 0) 
                System.out.println("ab is greater than Ab"); 
            else
                System.out.println("ab is equal to Ab"); 
        } 
  
        catch (ParseException e) { 
  
            System.out.println(e); 
        } 
        catch (NullPointerException e) { 
  
            System.out.println(e); 
        } 
    } 
}

输出：

ab is less than Ab

范例2：

// Java program to demonstrate 
// compare() method 
  
import java.text.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // Creating and initializing RuleBasedCollator Object 
            RuleBasedCollator col 
                = new RuleBasedCollator("< a< b< c< d"); 
  
            // Creating an initializing 
            // object for comparison 
            Object obj1 = null; 
  
            // Creating an initializing 
            // Object for comparison 
            Object obj2 = "Ab"; 
  
            // compare both object 
            // using compare() mehtod 
            int i 
                = col.compare((String)obj1, (String)obj2); 
  
            // display result 
            if (i < 0) 
                System.out.println("ab is less than Ab"); 
            else if (i > 0) 
                System.out.println("ab is greater than Ab"); 
            else
                System.out.println("ab is equal to Ab"); 
        } 
  
        catch (ParseException e) { 
  
            System.out.println(e); 
        } 
        catch (NullPointerException e) { 
            System.out.println("one of the object is null"); 
            System.out.println(e); 
        } 
    } 
}

输出：

one of the object is null
java.lang.NullPointerException

参考： https://docs.oracle.com/javase/9/docs/api/java/text/RuleBasedCollator.html#compare-java.lang.String-java.lang.String-

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注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 RuleBasedCollator compare() method in Java with Example。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。