一、基本使用方式
语法
1、获取根元素
Element root = document.getRootElement()
;
2、获取某个元素下的子元素
Element db_element = root.element(
"db"
)
;
3、获取元素的子元素集合1
List<Element> db_list = db_element.elements()
;//所有子元素
4、获取元素属性的值
element.attributeValue(
"name"
)；
5、获取元素的内容
element.getText()
;
6、获取元素的子元素集合2
element.elements(
"user"
)
;//指定名称的子元素集合
实战
<users>
<user no="2017">
<name>狗蛋</name>
<age>17</age>
</user>
<user no="2018">
<name>李狗蛋</name>
<age>19</age>
</user>
</users>
1、导入dom4j的jar包，遍历
public void
test4j
()
throws
DocumentException {
//创建解析器
SAXReader reader =
new
SAXReader()
;
org.dom4j.Document document = reader.read(
new
File(
"src/userInfo.xml"
))
;
org.dom4j.Element root = document.getRootElement()
;
List<org.dom4j.Element> list = root.elements()
;
for
(org.dom4j.Element e:list){
//获取属性值
String no = e.attributeValue(
"no"
)
;
String name = e.element(
"name"
).getText()
;
String age = e.element(
"age"
).getText()
;
System.
out
.println(no+name+age)
;
}
}
二、选择器使用
语法
1、获取节点集合
List<Node> list= document.selectNodes(
"users/user/name"
)
;
2、获取节点的节点名称
node.getName();
3、获取节点的值
node.getText()
;
4、获取节点的属性值
node.valuesOf("@no");
实战
2、还需导入jaxen-1.1-beta-6.jar,进行xpath操作
public void
testdom4j_xpath
()
throws
DocumentException {
SAXReader reader =
new
SAXReader()
;
org.dom4j.Document document = reader.read(
new
File(
"src/userInfo.xml"
))
;
List<Node> list= document.selectNodes(
"users/user/name"
)
;
for
(Node node:list){
String qname = node.getName()
;
String name = node.getText()
;
System.
out
.println(qname+
"--"
+name)
;
}
List<org.dom4j.Node> list1 = document.selectNodes(
"users/user"
)
;
for
(Node node:list1){
String no = node.valueOf(
"@no"
)
;
System.
out
.println(
no
)
;
}
}
三、创建，修改XML文档
语法
1、获取document对象
Document document = DocumentHelper.createDocument();
2、创建根元素
Element root = document.addElement(
"users"
);
3、添加子节点
Element e = element.addElement("name");
4、设置属性
Element e = element.setText("张三");
5、删除节点e的子节点element
e.remove(element);
四、属性
语法
1.取得某节点下的某属性
Attribute attribute=element.attribute("id");
2.取得属性的文字
String text=attribute.getText();
3.删除某属性
Attribute attribute=root.attribute("size"); root.remove(attribute);
4.遍历某节点的所有属性
Element root=document.getRootElement();
for(Iterator it=root.attributeIterator();it.hasNext();){
Attribute attribute = (Attribute) it.next();
String text=attribute.getText();
System.out.println(text);
}
5.设置某节点的属性和文字.
newMemberElm.addAttribute("name", "sitinspring");
6.设置属性的文字
Attribute attribute=root.attribute("name"); attribute.setText("csdn");
五、小综合
根据xml文档，在数据库创建表
<?
xml version
="1.0"
encoding
="UTF-8"
?>
<!--
解析以下XML文档，根据配置信息要求实现:
1.连接指定数据库
2.创建table
-->
<config>
<db
id
="mysql"
>
<property
name
="driverClass"
>
com.mysql.jdbc.Driver
</property>
<property
name
="url"
>
jdbc:mysql://127.0.0.1:3306/test
</property>
<property
name
="user"
>
root
</property>
<property
name
="password"
>
root
</property>
</db>
<table
tableName
="tbuser"
>
<property
name
="id"
column
="uid"
type
="integer"
></property>
<property
name
="account"
column
="username"
type
="varchar"
length
="255"
></property>
<property
name
="password"
column
="passowrd"
type
="varchar"
length
="255"
></property>
</table>
</config>
package homework;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class CreateDB {
String driverClass="";
String url="";
String user="";
String password="";
String tableName="";
public static void main(String[] args) {
try {
new CreateDB().doit();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} catch (DocumentException e) {
e.printStackTrace();
}
}
public String getsql() throws DocumentException {
SAXReader reader = new SAXReader();
Document document = reader.read("src/config.xml");
//获取根节点
Element root = document.getRootElement();
//获取db节点
Element db_element = root.element("db");
//获取db节点里面的节点集合
List<Element> db_list = db_element.elements();
for(int i=0;i<db_list.size();i++){
Element element = db_list.get(i);
if("driverClass".equals(element.attributeValue("name"))){
driverClass = element.getText();
}
else if("url".equals(element.attributeValue("name"))){
url = element.getText();
}
else if("user".equals(element.attributeValue("name"))){
user = element.getText();
}
else if("password".equals(element.attributeValue("name"))){
password = element.getText();
}
}
ArrayList<String> sqls = new ArrayList<>();
//获取tableNmae节点
Element tb_element = root.element("table");
//获取表名称
tableName =tb_element.attributeValue("tableName");
//获取元素集合
List<Element> tb_list = tb_element.elements();
for(int i=0;i<tb_list.size();i++){
Element element = tb_list.get(i);
String column = element.attributeValue("column");
if("integer".equals(element.attributeValue("type"))){
sqls.add(column+" "+"int");
}else if("varchar".equals(element.attributeValue("type"))){
String lenght = element.attributeValue("length");
sqls.add(column+" "+" varchar("+lenght+") ");
}
}
String sql="create table "+tableName+" (";
for(int i=0;i<sqls.size();i++){
//防止，引发的错误
if(i!=sqls.size()-1){
sql = sql+sqls.get(i)+" , ";
}else {
sql = sql+sqls.get(i);
}
}
sql = sql+" );";
return sql;
}
public void doit() throws ClassNotFoundException, SQLException, DocumentException {
String sql=getsql();
System.out.println(driverClass+" "+url+" "+user+" "+password);
Class.forName(driverClass);
Connection connection = DriverManager.getConnection(url,user,password);
Statement statement = connection.createStatement();
System.out.println(sql);
statement.execute(sql);
}
}