Java ChoiceFormat format()用法及代码示例

java.text.ChoiceFormat类的format()方法用于获取附加限制字符串格式的字符串生成器，该格式值的特定限制值作为参数传递，该文本作为参数传递给该方法。

用法:

public StringBuffer format(double number,
                         StringBuffer toAppendTo,
                         FieldPosition status)

参数：此方法采用以下参数，如下所示

number:这是选择格式对象的特定限制，必须为其找到格式并附加格式
toAppendTo:这是要附加格式的新文本
status:确定是否没有特殊状态要返回

返回值：此方法以StringBuffer对象的形式返回文本和格式的附加值。

异常：如果toAppendto值为null，则此方法引发NullPointerException。

下面是说明format()方法的示例：

示例1:

// Java program to demonstrate 
// format() method 
  
import java.text.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating and initializing ChoiceFormat 
            ChoiceFormat cf1 
                = new ChoiceFormat( 
                    "4#wed| 5#thu | 6#fri | 7#sat"); 
  
            // creating and initializing StringBuffer 
            StringBuffer str = new StringBuffer("Sun"); 
  
            // getting the required format with appended text 
            // ChoiceFormat Object 
            // using format() method 
            StringBuffer vlaue = cf1.format(6, str, null); 
  
            // display the result 
            System.out.print("Formated text with appended value: "
                             + vlaue.toString()); 
        } 
        catch (NullPointerException e) { 
            System.out.println("str is null"); 
            System.out.println("Exception thrown: " + e); 
        } 
    } 
}

输出：

Formated text with appended value: Sunfri

示例2:

// Java program to demonstrate 
// format() method 
  
import java.text.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating and initializing ChoiceFormat 
            ChoiceFormat cf1 
                = new ChoiceFormat( 
                    "4#wed| 5#thu | 6#fri | 7#sat"); 
  
            // creating and initializing StringBuffer 
            StringBuffer str = null; 
  
            // getting the required format with appended text 
            // ChoiceFormat Object 
            // using format() method 
            StringBuffer vlaue = cf1.format(6, str, null); 
  
            // display the result 
            System.out.print("Formated text with appended value: "
                             + vlaue.toString()); 
        } 
        catch (NullPointerException e) { 
            System.out.println("str is null"); 
            System.out.println("Exception thrown: " + e); 
        } 
    } 
}

输出：

str is null
Exception thrown: java.lang.NullPointerException

参考： https://docs.oracle.com/javase/9/docs/api/java/text/ChoiceFormat.html#format-double-java.lang.StringBuffer-java.text.FieldPosition-

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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 ChoiceFormat format() method in Java with Examples。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。