使用到的工具和软件有:IntelliJ IDEA 各种版本, dom4j-1.6.1, 一个xml文件;

 1.查看xml文件的格式，便于后面的模拟输出

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE books [
        <!ELEMENT books (book+)>

        <!ELEMENT book (name, author, price)>

        <!ATTLIST book id CDATA #REQUIRED>

        <!ELEMENT name (#PCDATA)>
        <!ELEMENT author (#PCDATA)>
        <!ELEMENT price (#PCDATA)>
        ]>
<books>
    <book id="1">
        <name>测试1</name>
        <author>作者1</author>
        <price>25.0</price>
    </book>
    <book id="2">
        <name>测试2</name>
        <author>作者2</author>
        <price>50</price>
    </book>
    <book id="3">
        <name>测试3</name>
        <author>作者3</author>
        <price>2.5</price>
    </book>
</books>

 

 

2.导入dom4j框架包

 

3.新建Test测试类

 

 

 

4.导入各种包，idea中可在使用时快捷加载 ,所有异常只做抛出不做处理

1 import org.dom4j.Attribute;
2 import org.dom4j.Document;
3 import org.dom4j.DocumentException;
4 import org.dom4j.Element;
5 import org.dom4j.io.SAXReader;
6 import java.io.File;
7 import java.lang.reflect.InvocationTargetException;
8 import java.util.Iterator;

 

5.创建StringBuilder对象，用于模拟输出，实例化SAXReader类 

//不做异常处理 只抛出
public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException, DocumentException {

       //创建StringBuilder对象，收集数据信息
        StringBuilder sb = new StringBuilder();
        //加载SAXReader类
        Class<?> cf =  Class.forName("org.dom4j.io.SAXReader");
        //实例化SAXReader类
        SAXReader sr = (SAXReader)cf.getDeclaredConstructor().newInstance();    

 

6.读取books.xml节点信息

        //SAXReader的read() 读取 books.xml
        Document bdoc = sr.read(new File("src/com/test/dom/domain/books.xml"));
        //getRootElement() 拿到根节点信息
        Element rootElement = bdoc.getRootElement();
        //elementIterator 拿到根节点的子节点信息
        Iterator<Element> biter = rootElement.elementIterator();    

 

7.拼接数据信息  模拟输出文档原本信息

        //hasNext判断是否存在下一个元素
        while (biter.hasNext())
        {
            //next()指针下移，返回该指针所指向的元素
            Element next = biter.next();
            Attribute id = next.attribute("id");
            //拼接<book id = "1">
            sb.append("<");
            //拿到book
            sb.append(next.getName());
            sb.append(" ");
            //拿到key值  'id'
            sb.append(id.getName());
            sb.append("=");
            //拿到value值  '1'
            sb.append(id.getValue());
            sb.append(">");
            //拿到book下的子节点信息
            Iterator<Element> iter = next.elementIterator();
            sb.append("\n");
            while(iter.hasNext())
            {
                //拼接
                //<name> </name>
                //<author></author>
                //<price></price>
                Element next1 = iter.next();
                sb.append("\t");
                sb.append("<");
                sb.append(next1.getName());
                sb.append(">");
                sb.append(next1.getStringValue());
                sb.append("<");
                sb.append("/");
                sb.append(next1.getName());
                sb.append(">");
                sb.append("\n");
            }
            //拼接</book>
            sb.append("<");
            sb.append("/");
            sb.append(next.getName());
            sb.append(">");
            sb.append("\n");
        }    

 

8. 输出StringBuilder信息

        //输出信息
        System.out.println(sb);    

 

 

线程安全：StringBuffer线程安全，StringBuilder线程不安全。缓冲区：StringBuffer直接使用toStringCache构造字符串。StringBuilder复制字符数组再构造。性能：StringBuilder的性能要远大于StringBuffer。

标签：XML,JAVA,DOM,SAXReader,StringBuilder,dom4j,import,sb,append
来源： https://www.cnblogs.com/zhuimu/p/14276302.html