Java CompoundName getPrefix()用法及代码示例

javax.naming.CompoundName类的getPrefix()方法用于获取复合名称对象，该复合名称对象的组件由该复合名称中的组件前缀组成。我们需要停止从此复合名称对象中提取前缀的位置作为参数传递。返回的复合名称对象和此复合名称对象具有相同的语法。如果我们对该复合名称进行了任何更改，而不会影响返回的名称，反之亦然。

用法:

public Name getPrefix(int posn)

参数：此方法接受posn，它是要在其处停止的组件的从0开始的索引。必须在[0，size()]范围内。

返回值：此方法返回一个由[0，posn)范围内的索引组成的复合名称。

异常：如果posn在指定范围之外，则此方法引发ArrayIndexOutOfBoundsException。

以下示例程序旨在说明CompoundName.getPrefix()方法：
程序1:

// Java program to demonstrate 
// CompoundName.getPrefix() 
  
import java.util.Properties; 
import javax.naming.CompoundName; 
import javax.naming.InvalidNameException; 
  
public class GFG { 
    public static void main(String[] args) 
        throws InvalidNameException 
    { 
  
        // need properties for CompoundName 
        Properties props = new Properties(); 
        props.put("jndi.syntax.separator", "@"); 
        props.put("jndi.syntax.direction", 
                  "left_to_right"); 
  
        // create compound name object 
        CompoundName CompoundName1 
            = new CompoundName( 
                "1@2@3@4@5@6@7", 
                props); 
  
        // apply getPrefix() 
        CompoundName newCompoundName 
            = (CompoundName) 
                  CompoundName1 
                      .getPrefix(3); 
  
        // print value 
        System.out.println( 
            "New CompoundName Object:"
            + newCompoundName); 
    } 
}

输出：

New CompoundName Object:1@2@3

程序2:

// Java program to demonstrate 
// CompoundName.getPrefix() method 
  
import java.util.Properties; 
import javax.naming.CompoundName; 
import javax.naming.InvalidNameException; 
  
public class GFG { 
    public static void main(String[] args) 
        throws InvalidNameException 
    { 
  
        // need properties for CompoundName 
        Properties props = new Properties(); 
        props.put("jndi.syntax.separator", "/"); 
        props.put("jndi.syntax.direction", 
                  "left_to_right"); 
  
        // create compound name object 
        CompoundName CompoundName1 
            = new CompoundName( 
                "c/e/d/v/a/b/z/y/x/f", 
                props); 
  
        // apply getPrefix() 
        CompoundName newCompoundName 
            = (CompoundName) 
                  CompoundName1.getPrefix(8); 
  
        // print value 
        System.out.println( 
            "New CompoundName Object:"
            + newCompoundName); 
    } 
}

输出：

New CompoundName Object:c/e/d/v/a/b/z/y

参考文献：https://docs.oracle.com/javase/10/docs/api/javax/naming/CompoundName.html#getPrefix(int)

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注：本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 CompoundName getPrefix() 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。