Java中的 Collator compare(Object, Object) 方法与示例

Java.text.Collator类的compare()方法用于比较两个对象的强度，它会根据结果返回 0，正负值作为输出。

句法：

public int compare(Object o1, Object o2)

参数：此方法采用两个将要进行比较的对象。
返回值：如果第一个对象等于、大于或小于另一个对象，则分别返回零、正值和负值。
异常：如果无法将参数强制转换为字符串，则此方法将引发ClassCastException 。
以下是说明compare()方法的示例：
示例 1：

Java

// 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 Collator Object
            Collator col = Collator.getInstance();
 
            // Creating an initializing
            // object for comparison
            Object obj1 = "ab";
 
            // Creating an initializing
            // Object for comparison
            Object obj2 = "Ab";
 
            // compare both object
            // using compare() method
            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 (ClassCastException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出：

ab is less than Ab

示例 2：

Java

// 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 Collator Object
            Collator col = Collator.getInstance();
 
            // Creating an initializing object for comparison
            Object obj1 = "ab";
 
            // Creating an initializing Object for comparison
            Object obj2 = 1234;
 
            // compare both object
            // using compare() method
            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 (ClassCastException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出：

Exception thrown :
 java.lang.ClassCastException:
 java.lang.Integer cannot be cast to java.lang.String

参考： https://docs.oracle.com/javase/9/docs/api/ Java/text/Collator.html#compare-java.lang.Object-java.lang.Object-