如何在Java中将XML读取到POJO列表中? [英] How to read XML to a list of POJOs in Java?
问题描述
我是XML的新手，我试图读取XML页面并将其内容存储在arraylist中.
I'm new to XML and im trying to read in an XML page and store its contents in an arraylist.
到目前为止，我似乎已经能够使arraylist充满第一个内容，因为当我尝试isEmpty时，它返回false.所以肯定有一些东西. 但是，当我尝试调用过高的tostring方法，甚至尝试为此调用任何单独的类别时，它只会返回空吗?
So far i seem to have been able to get the arraylist filled with the first content, as when i tried an isEmpty, it returned false. so there is definitely containing something. However, when i try to call the overided tostring method, or even try to call any individual category for that matter, it just returns empty?
任何人都可以帮忙吗?
以下代码可用于:
package test;
import java.io.File;
import java.util.ArrayList;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
public class xmlmx {
public static void main(String[] args) {
ArrayList<Anime> list = new ArrayList<Anime>();
try {
File inputFile = new File("c:\\code\\ad\\XMLDB.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(inputFile);
doc.getDocumentElement().normalize();
System.out.println("Root element: " + doc.getDocumentElement().getNodeName());
NodeList nList = doc.getElementsByTagName("Anime");
System.out.println("----------------------------");
for (int temp = 0; temp < nList.getLength(); temp++) {
Node nNode = nList.item(temp);
System.out.println("\nCurrent Element :" + nNode.getNodeName());
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) nNode;
list.add(new Anime(eElement.getAttribute("ID"),
eElement.getAttribute("name"),
eElement.getAttribute("altname"),
eElement.getAttribute("seasons"),
eElement.getAttribute("episodes"),
eElement.getAttribute("status"),
eElement.getAttribute("DS"),
eElement.getAttribute("have"),
eElement.getAttribute("left"),
eElement.getAttribute("plot"),
eElement.getAttribute("connect"),
eElement.getAttribute("image")));
System.out.println(list.get(0).toString());
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
arraylist的类型是anime，这里是一个类:
the arraylist is of type anime, a class here:
package test;
class Anime{
private String ID;
private String name;
private String altname;
private String seasons;
private String episodes;
private String status;
private String DS;
private String have;
private String left;
private String plot;
private String connect;
private String image;
public Anime(String ID,
String name,
String altname,
String seasons,
String episodes,
String status,
String DS,
String have,
String left,
String plot,
String connect,
String image) {
this.ID = ID;
this.name = name;
this.altname = altname;
this.seasons = seasons;
this.episodes = episodes;
this.status = status;
this.DS = DS;
this.have = have;
this.left = left;
this.plot = plot;
this.connect = connect;
this.image = image;
}
/*
getters and setters here...
*/
@Override
public String toString() {
return "Anime [ID=" + ID +
", name=" + name +
", altname=" + altname +
", seasons=" + seasons +
", episodes=" + episodes +
", status=" + status +
", DS=" + DS +
", have=" + have +
", left=" + left +
", plot=" + plot +
", connect=" + connect +
", image=" + image + "]";
}
}
最后，这是xml:
<?xml version="1.0" encoding="UTF-8"?>
<Anime>
<record ID="BL1">
<name>Bleach</name>
<altname>Burichi</altname>
<seasons>16</seasons>
<episodes>366</episodes>
<status>Finished</status>
<sound>Dubbed</sound>
<have>All</have>
<left>-/-</left>
<plot>Ichigo gets grim reaper powers, fights reapers, hollows and everything in between</plot>
<connect>Bleach movies</connect>
<image>images/bleach.jpg</image>
</record>
</Anime>
任何帮助将不胜感激，谢谢
any help would be greatly appreciated, thank you
推荐答案
基本上，您对w3c dom xml元素的理解是错误的. 名称:"，"altname"等不是"Animie"元素的属性.它们是"record"节点的子节点".因此，您首先必须通过迭代"Animie"元素的子节点来获取"record"节点.您可以遍历"record"元素的子节点，以便可以填充Anime对象.
Hi basically your understanding about the w3c dom xml element is wrong. "name:, "altname" etc are not attributes of "Animie" element. those are "child nodes" of "record" node. So first you have to fetch "record" node by iterating child nodes of "Animie" element. Then you can iterate through the child nodes of "record" element so that you can populate your Anime object.
这是您的"xmlmx类"的简单实现，我必须使用映射，因为您省略了setter方法，只需尝试将xml概念固定在脑海中就可以改进.
Here's a simple implementation of your "xmlmx class that works. I had to use a map because you have ommitted the setter methods, this can be improved just trying to fix the xml concepts in your head.
只需用这个替换您的班级.
Just replace your class with this.
package test;
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import com.sun.org.apache.xerces.internal.dom.DeferredElementImpl;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
public class xmlmx {
public static void main(String[] args) {
ArrayList<Anime> list = new ArrayList<Anime>();
try {
File inputFile = new File("test.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(inputFile);
doc.getDocumentElement().normalize();
System.out.println("Root element: " + doc.getDocumentElement().getNodeName());
Node recordNode = null;
NodeList childNodes = doc.getFirstChild().getChildNodes();
for (int i = 0; i < childNodes.getLength(); i++) {
if (childNodes.item(i).getNodeName().equals("record")) {
recordNode = childNodes.item(i);
break;
}
}
System.out.println("----------------------------");
Map<String, String> map = new HashMap<>();
if (recordNode != null) {
NodeList subNodes = recordNode.getChildNodes();
for (int i = 0; i < subNodes.getLength(); i++) {
if (subNodes.item(i).getNodeType() == Node.ELEMENT_NODE) {
map.put(subNodes.item(i).getNodeName(), subNodes.item(i).getTextContent());
}
}
}
String id = ((DeferredElementImpl) recordNode).getAttribute("ID");
list.add(new Anime(id,
map.get("name"),
map.get("altname"),
map.get("seasons"),
map.get("episodes"),
map.get("status"),
map.get("DS"),
map.get("have"),
map.get("left"),
map.get("plot"),
map.get("connect"),
map.get("image")));
System.out.println(list.get(0));
} catch (Exception e) {
e.printStackTrace();
}
}
}
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