Java实现数据库数据生成XML文件的通用程序

转自http://tieba.baidu.com/p/136643159
原篇内容缺失，本篇对其进行整理，以备后用。

本篇使用w3c.dom解析。方法实现将查询结果集（ResultSet对象）和要生成的XML文件的路径传人，然后自己指派属性名称、元素名称并与对应的查询结果集中的字段对应，最后调用designOver()函数生成所期望的XML文件。

方法包含5个类：CreateXmlFile.java, XmlDisposal.java, SaveAttrName.java, SaveEleName.java, WriteXmlFile.java。

SaveAttrName.java：

public class SaveAttrName {
private String attrName;
private int index;
public SaveAttrName(String attrName, int index) {
super();
this.attrName = attrName;
this.index = index;
}
public String getAttrName() {
return attrName;
}
public void setAttrName(String attrName) {
this.attrName = attrName;
}
public int getIndex() {
return index;
}
public void setIndex(int index) {
this.index = index;
}

}

SaveEleName.java：

public class SaveEleName {
private String eleName;
private int index;
public SaveEleName(String eleName, int index) {
super();
this.eleName = eleName;
this.index = index;
}
public String getEleName() {
return eleName;
}
public void setEleName(String eleName) {
this.eleName = eleName;
}
public int getIndex() {
return index;
}
public void setIndex(int index) {
this.index = index;
}

}

XmlDisposal.java：

public class XmlDisposal {

private ResultSet rs; //查询结果集
private String url; //要生成的xml文件的路径
private ArrayList attrList = new ArrayList(); //用来存储属性名和字段索引的集合类
private ArrayList eleList = new ArrayList(); //用来存储元素名和字段索引的集合类
private String root;
private String rootChild;

public void setResultSet(ResultSet rs, String url) {
this.rs = rs;
this.url = url;
}

public void setRootName(String root, String rootChild) {
this.root = root;
this.rootChild = rootChild;
}

public void collectData(String nameStr, int index, String type) {
if(type.equals("attribute")) {
attrList.add(new SaveAttrName(nameStr, index));
} else {
eleList.add(new SaveEleName(nameStr, index));
}
}

public void startWrite() {
new WriteXmlFile(attrList, eleList, rs, url).create(root, rootChild);
}
}

WriteXmlFile.java：

public class WriteXmlFile {

private ResultSet rs;
private String url;
private ArrayList arrtList;
private ArrayList elemList;

public WriteXmlFile(ArrayList arrtList,
ArrayList elemList, ResultSet rs, String url) {
super();
this.rs = rs;
this.url = url;
this.arrtList = arrtList;
this.elemList = elemList;
}

/**
* @param root xml文件的根元素名
* @param rootchild
*/
public void create(String root, String rootChild) {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
Document document = null;
try {
DocumentBuilder db = dbf.newDocumentBuilder();
document = (Document) db.newDocument();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Element rootElem = document.createElement(root);
document.appendChild(rootElem);
Iterator attr = arrtList.iterator();
Iterator elem = elemList.iterator();
try {
while (rs.next()) {
Element rootChildElem = document.createElement(rootChild);
while (attr.hasNext()) {
// 循环到属性集合中取元素名称，之后从查询结果集中取得数据，创建元素属性
SaveAttrName temp = (SaveAttrName) attr.next();
rootChildElem.setAttribute(temp.getAttrName(), rs
.getString(temp.getIndex()).trim());
}
rootElem.appendChild(rootChildElem);
while (elem.hasNext()) {
// 循环到元素集合中取元素名称，之后从查询结果集中取得数据，创建结点
SaveEleName temp = (SaveEleName) elem.next();
Element tempElem = document
.createElement(temp.getEleName());
Text tempTextElem = document.createTextNode(rs.getString(
temp.getIndex()).trim());
tempElem.appendChild(tempTextElem);
rootChildElem.appendChild(tempElem);
}
attr = arrtList.iterator(); // 重复循环到集合中取值
elem = elemList.iterator(); // 重复循环到集合中取值
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
writeXml(document);
}

private void writeXml(Document doc) {
try {
FileOutputStream out = new FileOutputStream(url);
OutputStreamWriter outWriter = new OutputStreamWriter(out);
((XmlDocument) doc).write(outWriter, "UTF-8");
outWriter.close();
out.close();
System.out.print("\nWrite xmlfile successful!\n");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

注明：XmlDocument这个类的使用需要引入crimson.jar

CreateXmlFile.java

public class CreateXmlFile {

private ResultSet rs; //查询结果集
private String url;  //要生成的xml文件的路径
private XmlDisposal disposal; //自定义的用来收集和处理数据的类
private String root; //xml文件的根元素名称
private String rootChild; //根结点的子结点的元素名称
public CreateXmlFile(ResultSet rs, String url) {
super();
this.rs = rs;
this.url = url;
disposal = new XmlDisposal();
disposal.setResultSet(this.rs, this.url);
}

//设定xml文件的根元素名称
public void setRootEleName(String root, String rootChild) {
this.root = root;
this.rootChild = rootChild;
disposal.setRootName(this.root, this.rootChild);
}

//设置属性的名字和索引位置，位置从1开始
public void serAttrName(String nameStr, int index) {
disposal.collectData(nameStr, index, "attribute");
}

//设置元素的名字和索引位置，位置从1开始
public void setEleName(String nameStr, int index) {
disposal.collectData(nameStr, index, "element");
}

public void designOver() {
disposal.startWrite();
}
}

测试类test.java

public static void main(String[] args) {
// TODO Auto-generated method stub

Connection conn = DBUtil.getConnection();
Statement stmt;
try {
stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(DBUtil.getSql());
/*int columnCount = rs.getMetaData().getColumnCount();
while (rs.next()) {
//rs.afterLast();
//System.out.println(rs.getRow());
for (int i = 1; i <= columnCount; i++) {
System.out.print(rs.getObject(i) + "\t");

}

}*/
CreateXmlFile xml = new CreateXmlFile(rs, "d:/demo.xml");
xml.setRootEleName("books","book");
xml.serAttrName("title", 1);
//xml.setEleName("title", 1);
xml.setEleName("author", 2);
xml.setEleName("year", 3);
xml.setEleName("price", 4);
xml.designOver();
rs.close();
stmt.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

在D盘根目录下生成demo.xml文件：

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

<books>
<book title="Harry Potter">
<author>J K. Rowling</author>
<year>2005-01-01</year>
<price>30</price>
</book>
<book title="Everyday Italian">
<author>Giada De Laurentiis</author>
<year>2005-01-01</year>
<price>30</price>
</book>
<book title="Learning XML">
<author>Erik T. Ray</author>
<year>2003-01-01</year>
<price>40</price>
</book>
<book title="XQuery Kick Start">
<author>James McGovern, Per Bothner</author>
<year>2003-01-01</year>
<price>50</price>
</book>
</books>

数据库book表记录如下：

+-------------------+-----------------------------+------+-------+
| title             | author                      | year | price |
+-------------------+-----------------------------+------+-------+
| Harry Potter      | J K. Rowling                | 2005 | 30    |
| Everyday Italian  | Giada De Laurentiis         | 2005 | 30    |
| Learning XML      | Erik T. Ray                 | 2003 | 40    |
| XQuery Kick Start | James McGovern, Per Bothner | 2003 | 50    |
+-------------------+-----------------------------+------+-------+
4 rows in set