java 处理XML(dom4j-1.6.1)

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Java 处理xml有很多框架，今天使用主流框架dom4j-1.6.1

下载地址：http://www.dom4j.org/dom4j-1.6.1/

Dom4j，是一款开源的处理XML, XPath, and XSLT的框架，它容易使用，并且完全支持DOM, SAX, and JAXP.

写XML 文件

首先创建一个XMLwriter,吧文件写到output.xml

// lets write to a file
XMLWriter writer = new XMLWriter(
new FileWriter( "output.xml" )
);

创建一个xml Document

Document document = DocumentHelper.createDocument();

接着创建元素的根节点

Element root = document.addElement( "root" );

接下来在根节点添加元素和属性

root.addElement( "author" )
.addAttribute( "name", "James" )
.addAttribute( "location", "UK" )
.addText( "James Strachan" );

最后保存文件

writer.write( document );
writer.close();

这样保存效果很差，很不美观，如果想要漂亮的效果

OutputFormat format = OutputFormat.createPrettyPrint();
XMLWriter writer = new XMLWriter(new FileWriter("output.xml"), format);

最终的：

import java.io.FileWriter;
import java.io.IOException;import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;public class XMLWriterTest {
/**
* @author Young
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
OutputFormat format = OutputFormat.createPrettyPrint();
XMLWriter writer = new XMLWriter(new FileWriter("output.xml"), format); Document document = DocumentHelper.createDocument();
Element root = document.addElement("root"); root.addComment("This is xml comment");
root.addElement("author").addAttribute("name", "James")
.addAttribute("location", "UK").addText("James Strachan");
writer.write(document);
writer.close();
}
}

输出效果如下：

<?xml version="1.0" encoding="UTF-8"?><root>

<author name="James" location="UK">James Strachan</author>
</root>

嵌套写XML

想要的效果如下：

<?xml version="1.0" encoding="UTF-8"?><StudentInfo Class="1">

<student name="Jack" Sex="Male" Birthday="1988/07/05">100001
<scores score="90"/>
</student>
<student name="Lisa" Sex="Female" Birthday="1989/02/12">100002
<scores score="98"/>
</student>
<student name="Steven" Sex="Male" Birthday="1987/11/18">100003
<scores score="59"/>
</student>
<student name="Jenny" Sex="Female" Birthday="1989/03/18">100004
<scores score="69"/>
</student>
<student name="Lucy" Sex="Female" Birthday="1990/01/26">100005
<scores score="90"/>
</student>
<student name="Lewis" Sex="Male" Birthday="1989/04/06">100006
<scores score="82"/>
</student>
</StudentInfo>

每个student节点下设置一个score节点

并且所有student节点属性都一样，于是乎可以创建一个student bean专门用于数据传递：

/***
* This Class is for Student bean
* @author Young
*
*/
public class Student { private int stud_Id;
private String stud_Name;
private String sex;
private String birthday;
private String score; public int getStud_Id() {
return stud_Id;
} public void setStud_Id(int stud_Id) {
this.stud_Id = stud_Id;
} public String getStud_Name() {
return stud_Name;
} public void setStud_Name(String stud_Name) {
this.stud_Name = stud_Name;
} public String getSex() {
return sex;
} public void setSex(String sex) {
this.sex = sex;
} public String getBirthday() {
return birthday;
} public void setBirthday(String birthday) {
this.birthday = birthday;
} public String getScore() {
return score;
} public void setScore(String score) {
this.score = score;
} /**
* This method is a constructor
*
* @author Young
* @param id
* @param name
* @param sex
* @param birthday
* @param score
*/
public Student(int id, String name, String sex, String birthday,
String score) { this.stud_Id = id;
this.stud_Name = name;
this.sex = sex;
this.birthday = birthday;
this.score = score;
}
}

接下来初始化并放到一个ArrayList：

static List<Student> students = new ArrayList<Student>(); /**
* @author Young
*/
public static void init() {
Student stu1 = new Student(100001, "Jack", "Male", "1988/07/05", "90");
Student stu2 = new Student(100002, "Lisa", "Female", "1989/02/12", "98");
Student stu3 = new Student(100003, "Steven", "Male", "1987/11/18", "59");
Student stu4 = new Student(100004, "Jenny", "Female", "1989/03/18",
"69");
Student stu5 = new Student(100005, "Lucy", "Female", "1990/01/26", "90");
Student stu6 = new Student(100006, "Lewis", "Male", "1989/04/06", "82");
students.add(stu1);
students.add(stu2);
students.add(stu3);
students.add(stu4);
students.add(stu5);
students.add(stu6); }

创建一个写到XML文件的方法：

/**
* @author Young
* @param studs
* @return
* @throws IOException
*/
public static Document createDocument(List<Student> studs)
throws IOException { OutputFormat format = OutputFormat.createPrettyPrint();
XMLWriter writer = new XMLWriter(new FileWriter("output.xml"), format); Document document = DocumentHelper.createDocument();
Element root = document.addElement("StudentInfo"); root.addAttribute("Class", "1");
root.addComment("This is Class 1 student information"); for (Student std : studs) {
root.addElement("student").addAttribute("name", std.getStud_Name())
.addAttribute("Sex", std.getSex())
.addAttribute("Birthday", std.getBirthday())
.addText(Integer.toString(std.getStud_Id()))
.addElement("scores").addAttribute("score", std.getScore());
}
writer.write(document);
writer.close();
return document;
}

读取XML文件

与写文件相似，首先创建一个SAXReader

SAXReader reader = new SAXReader()

接着创建XML document

Document document = reader.read(file);

创建根元素并从document获取

Element root = document.getRootElement();

创建元素迭代器或属性迭代器获取相关元素和属性

// iterate through child elements of root
for ( Iterator i = root.elementIterator(); i.hasNext(); ) {
Element element = (Element) i.next();
// do something
}
// iterate through attributes of root
for ( Iterator i = root.attributeIterator(); i.hasNext(); ) {
Attribute attribute = (Attribute) i.next();
// do something
}

以之前嵌套后的XML为例：

/**This method is for read XML
* @author Young
* @param file
* @throws DocumentException
*/
public static void readDocument(String file) throws DocumentException {
SAXReader reader = new SAXReader(); Document document = reader.read(file); Element root = document.getRootElement();
for (Iterator<?> i = root.elementIterator(); i.hasNext();) {
Element element = (Element) i.next();
if (!element.getName().equalsIgnoreCase("Student")) {
System.out.println("StudentInfo is:");
continue;
} // iterate through child elements of root with element name
// "student" for (Iterator<?> j = element.attributeIterator(); j.hasNext();) {
Attribute attribute = (Attribute) j.next();
System.out.print("attribute name " + attribute.getName()
+ " ->" + attribute.getName());
System.out.println(" attribute value " + attribute.getValue()); }
System.out.println("attribute value " + element.getText());
// get path
System.out.println("attribute name " + element.getName() + " ->"
+ element.getPath()); } }

可以通过：

getName/getPath/getValue 等方法是获取相关内容

运行结果：

attribute name name ->name attribute value Jack
attribute name Sex ->Sex attribute value Male
attribute name Birthday ->Birthday attribute value 1988/07/05
attribute value 100001attribute name student ->/StudentInfo/student
attribute name name ->name attribute value Lisa
attribute name Sex ->Sex attribute value Female
attribute name Birthday ->Birthday attribute value 1989/02/12
attribute value 100002attribute name student ->/StudentInfo/student
attribute name name ->name attribute value Steven
attribute name Sex ->Sex attribute value Male
attribute name Birthday ->Birthday attribute value 1987/11/18
attribute value 100003attribute name student ->/StudentInfo/student
attribute name name ->name attribute value Jenny
attribute name Sex ->Sex attribute value Female
attribute name Birthday ->Birthday attribute value 1989/03/18
attribute value 100004attribute name student ->/StudentInfo/student
attribute name name ->name attribute value Lucy
attribute name Sex ->Sex attribute value Female
attribute name Birthday ->Birthday attribute value 1990/01/26
attribute value 100005attribute name student ->/StudentInfo/student
attribute name name ->name attribute value Lewis
attribute name Sex ->Sex attribute value Male
attribute name Birthday ->Birthday attribute value 1989/04/06
attribute value 100006attribute name student ->/StudentInfo/student