向量指令和标量指令

向量指令和标量指令：有些大型机和巨型机 设置功能齐全的向量运算指令系统。

向量指令的基本操作对象是向量,即有序排列的一组数。

若指令为向量操作,则由指令确定向量操作数的地址（主存储器起始地址或向量寄存器号），并直接或隐含地指定如增量、向量长度等其他向量参数。

向量指令规定处理机按同一操作处理向量中的所有分量，可有效地提高计算机的运算速度。

不具备向量处理功能，只对单个量即标量进行操作的指令称为标量指令。

package Com.TableTest;

import java.io.File;  
import javax.xml.parsers.DocumentBuilder;  
import javax.xml.parsers.DocumentBuilderFactory;  
import org.w3c.dom.Document;  
import org.w3c.dom.Element;  
import org.w3c.dom.Node;  
import org.w3c.dom.NodeList;  
 
public class TableText_07 {  
 
    public void getAllUserNames(String fileName) {  
        try {  
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();  
            DocumentBuilder db = dbf.newDocumentBuilder();  
            File file = new File(fileName);  
            if (file.exists()) {  
                Document doc = db.parse(file);  
                Element docEle = doc.getDocumentElement();  
 
                // Print root element of the document  
                System.out.println("Root element of the document: "
                        + docEle.getNodeName());  
 
                NodeList studentList = docEle.getElementsByTagName("student");  
 
                // Print total student elements in document  
                System.out  
                        .println("Total students: " + studentList.getLength());  
 
                if (studentList != null && studentList.getLength() > 0) {  
                    for (int i = 0; i < studentList.getLength(); i++) {  
 
                        Node node = studentList.item(i);  
 
                        if (node.getNodeType() == Node.ELEMENT_NODE) {  
 
                            System.out  
                                    .println("=====================");  
 
                            Element e = (Element) node;  
                            NodeList nodeList = e.getElementsByTagName("name");  
                            System.out.println("Name: "
                                    + nodeList.item(0).getChildNodes().item(0)  
                                            .getNodeValue());  
 
                            nodeList = e.getElementsByTagName("grade");  
                            System.out.println("Grade: "
                                    + nodeList.item(0).getChildNodes().item(0)  
                                            .getNodeValue());  
 
                            nodeList = e.getElementsByTagName("age");  
                            System.out.println("Age: "
                                    + nodeList.item(0).getChildNodes().item(0)  
                                            .getNodeValue());  
                        }  
                    }  
                } else {  
                    System.exit(1);  
                }  
            }  
        } catch (Exception e) {  
            System.out.println(e);  
        }  
    }  
    public static void main(String[] args) {  
 
        TableText_07 parser = new TableText_07();  
        parser.getAllUserNames("H:\test2.xml");  
    }  
}

parser.getAllUserNames("H:\test2.xml");  测试获取的文件

<?xml version="1.0"?> 
<students> 
    <student> 
        <name>borter</name> 
        <grade>A</grade> 
        <age>22</age> 
    </student> 
    <student> 
        <name>Mary</name> 
        <grade>B</grade> 
        <age>23</age> 
    </student> 
    <student> 
        <name>Tom</name> 
        <grade>c</grade> 
        <age>24</age> 
    </student> 
</students>

测试获取的文件的结果集：

Root element of the document: students
Total students: 3
=====================
Name: borter
Grade: A
Age: 22
=====================
Name: Mary
Grade: B
Age: 23
=====================
Name: Tom
Grade: c
Age: 24