Java 中的 CompoundName getPrefix()方法，带示例

原文:https://www . geesforgeks . org/compound name-get prefix-method-in-Java-with-examples/

一个 javax.naming.CompoundName 类的 getPrefix() 方法用于获取一个复合名称对象，该复合名称对象的组件由该复合名称中的组件前缀组成。我们需要停止从这个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共享相同的语法。如果我们对这个复合名称进行任何更改，都不会影响返回的名称，反之亦然。

语法:

public Name getPrefix(int posn)

参数:该方法接受 posn，posn 是组件的从 0 开始的停止索引。必须在[0，size()]范围内。

返回值:该方法返回一个复合名称，由[0，posn 范围内索引处的组件组成。

异常:如果 posn 在指定范围之外，该方法抛出ArrayIndexOutOfBoundsException。

下面的程序说明了 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);
    }
}

Output:

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);
    }
}

Output:

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/compound name . html # getPrefix(int)

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