xml读取 数据库连接 生成xml 步骤详解及其代码和所需的包

先讲xml读取与生成，接下来通过xml读取来连接数据库。

第一：首先需要导入所需的jar文件：

如图所示：

下面代码是完整的可运行的解析xml文件的代码：package Dom4J;

import java.io.FileInputStream;

import java.util.List;

import org.dom4j.Attribute;

import org.dom4j.Document;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

public class TestDOM4JParseXML {

/**

* @Title: main

* @Description: TODO

* @author zhanghao

* @throws

*/

public static void main(String[] args) {

SAXReader reader = new SAXReader();

FileInputStream fis = null;

try{

fis = new FileInputStream("stu.xml");

//加载xml文档

Document doc = reader.read(fis);

//获取根元素

Element rootElt = doc.getRootElement();

System.out.println(rootElt.getName());

List elements = rootElt.elements();

System.out.println(elements.size());

for(int i=0;i<elements.size();i++){

Element elt = (Element)elements.get(i);

System.out.println(elt.getName());

List eltList = elt.attributes();

for(int j=0;j<eltList.size();j++){

Attribute attr = (Attribute)eltList.get(j);

System.out.println("\t属性："+attr.getName()+"="+attr.getValue());

}

List subEletList = elt.elements();

for(int j=0;j<subEletList.size();j++){

Element subElt = (Element)subEletList.get(j);

System.out.println("\t子元素："+subElt.getName()+"="+subElt.getText());

}

}

}catch (Exception e) {

e.printStackTrace();

}finally{

try{

if(fis !=null)

fis.close();

}catch (Exception e) {

e.printStackTrace();

}finally{

}

}

}

}

stu.xml文件代码如下：

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

<学生们>

<学生 id="001">

<姓名>张三</姓名>

<学号>001</学号>

</学生>

<学生>

<姓名>李四</姓名>

<学号>002</学号>

</学生>

<学生>

<姓名>王五</姓名>

<学号>003</学号>

</学生>

<学生 姓名="李刘" 学号="004"></学生>

</学生们>

下面代码是创建xml完整代码，复制直接可以正常运行：

package Dom4J;

import java.io.FileWriter;

import java.io.IOException;

import org.dom4j.Document;

import org.dom4j.DocumentHelper;

import org.dom4j.Element;

import org.dom4j.io.XMLWriter;

public class TestDOM4JCreateXML {

/**

* @Title: main

* @Description: TODO

* @author zhanghao

* @throws

*/

public static void main(String[] args) {

//创建Document实例

Document doc = DocumentHelper.createDocument();

Element rootElt = doc.addElement("select");

rootElt.addAttribute("name", "city");

Element city1Elt1 = rootElt.addElement("option");

city1Elt1.addAttribute("value", "1");

city1Elt1.addText("北京市");

Element city1Elt2 = rootElt.addElement("option");

city1Elt2.addAttribute("value", "2");

city1Elt2.addText("天津市");

Element city1Elt3 = rootElt.addElement("option");

city1Elt3.addAttribute("value", "3");

city1Elt3.addText("广西市");

Element city1Elt4 = rootElt.addElement("option");

city1Elt4.addAttribute("value", "4");

city1Elt4.addText("河南市");

doc.setXMLEncoding("UTF-8");

String xmlStr = doc.asXML();

System.out.println(xmlStr);

XMLWriter writer = null;

FileWriter fw = null;

try{

fw = new FileWriter("d:\\city.xml");

//doc.write(fw);

writer = new XMLWriter(fw);

writer.write(doc);

System.out.println("写入成功");

}catch(IOException e){

e.printStackTrace();

}finally{

try {

if(fw != null){

fw.close();

}

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

主要目录可以自己定义：

数据库基本链接源码：

DBUtil.java

package util;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

public class DBUtil {

private static DBUtil instance;

private jdbcInfo jdbcInfo;

private DBUtil(){

this.jdbcInfo = SystemUtil.getInstance().getJdbcInfo();

try {

Class.forName(this.jdbcInfo.getDriverClassName());

} catch (ClassNotFoundException e) {

e.printStackTrace();

}

}

public static DBUtil getInstance(){

if(instance == null){

instance = new DBUtil();

}

return instance;

}

public Connection getConnection(){

Connection conn = null;

try {

conn = DriverManager.getConnection(this.jdbcInfo.getUrl(),

this.jdbcInfo.getUsername(),

this.jdbcInfo.getPassword());

} catch (SQLException e) {

e.printStackTrace();

}

return conn;

}

public void free(Connection conn,java.sql.Statement stmt,ResultSet rs){

try {

if(rs != null)

rs.close();

if(stmt != null)

stmt.close();

if(conn != null)

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

}

JdbcInfo.java

package util;

public class jdbcInfo {

private String driverClassName;

private String url;

private String username;

private String password;

public String getDriverClassName() {

return driverClassName;

}

public void setDriverClassName(String driverClassName) {

this.driverClassName = driverClassName;

}

public String getUrl() {

return url;

}

public void setUrl(String url) {

this.url = url;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

}

SystemUtil.java

package util;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.Element;

import org.dom4j.Node;

import org.dom4j.io.SAXReader;

public class SystemUtil {

private static SystemUtil instance;

private jdbcInfo jdbcInfo;

private Element rootElt;

public static final String CFG_FILE_NAME = "system.cfg.xml";

private SystemUtil(){

SAXReader reader = new SAXReader();

try {

Document doc = reader.read(Thread.currentThread().getContextClassLoader().getResource(CFG_FILE_NAME));

System.out.println(doc);

rootElt = doc.getRootElement();

this.initJdbcInfo();

} catch (DocumentException e) {

e.printStackTrace();

}

}

private void initJdbcInfo(){

this.jdbcInfo = new jdbcInfo();

Node driverClassNode = rootElt.selectSingleNode("/system-configuration/jdbc-info/property[@name='driver_class']");

String driverClassName = driverClassNode.getText();

this.jdbcInfo.setDriverClassName(driverClassName);

Node urlNode = rootElt.selectSingleNode("/system-configuration/jdbc-info/property[@name='url']");

String url = urlNode.getText();

this.jdbcInfo.setUrl(url);

Node usernameNode = rootElt.selectSingleNode("/system-configuration/jdbc-info/property[@name='username']");

String username = usernameNode.getText();

this.jdbcInfo.setUsername(username);

Node passwordNode = rootElt.selectSingleNode("/system-configuration/jdbc-info/property[@name='password']");

String password = passwordNode.getText();

this.jdbcInfo.setPassword(password);

System.out.println(driverClassName);

}

public jdbcInfo getJdbcInfo(){

return this.jdbcInfo;

}

public static SystemUtil getInstance(){

if(instance == null){

instance = new SystemUtil();

}

return instance;

}

public static void main(String[] args){

new SystemUtil();

}

@Override

public String toString() {

return super.toString();

}

}

System.cfg.xml

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

<system-configuration>

<jdbc-info>

<property name="driver_class">com.mysql.jdbc.Driver</property>

<property name="url">jdbc:mysql://192.168.1.210:3306/my_db</property>

<property name="username">simope</property>

<property name="password">simope#CTCluster#2015</property>

</jdbc-info>

</system-configuration>

testClient.java

package tset;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import util.DBUtil;

public class TestClient {

/**

* @Title: main

* @Description: TODO

* @author zhanghao

* @date 2016-1-16 上午10:45:32

* @throws

*/

public static void main(String[] args) {

DBUtil util = DBUtil.getInstance();

Connection conn =null ;

PreparedStatement stmt = null;

ResultSet rs = null;

conn = util.getConnection();

String sql = "select * from sys_user";

try {

stmt = conn.prepareStatement(sql);

rs = stmt.executeQuery();

while(rs.next()){

int id = rs.getInt("userID");

String name = rs.getString("password");

System.out.println("id:"+id+"\tName:"+name);

}

} catch (SQLException e) {

e.printStackTrace();

}finally{

util.free(conn, stmt, rs);

}

}

}