android 使用Sax 读取xml

Sax 读取xml ,读取较快,最重要的是占用内存较少.

为了防止自己遗忘.留下我今天的足迹.也供大家参考.如果有误.请指正.

首先 在src 根目录下面创建一个Person.xml 文件.里面添加内容:

1.Person.xml

<?xml version="1.0" encoding="UTF-8"?>
<persons>
    <person id="23">
        <name>关大爷</name>
        <age>19</age>
    </person>
    <person id="20">
        <name>张飞</name>
        <age>18</age>
    </person>
      <person id="19">
        <name>主公</name>
        <age>20</age>
    </person>
</persons>

2.写一个 读取xml的personbean

Person

package com.example.bean;

public class Person {
    private int _id;
    private String _name;
    private int _age;
    
    public int get_id() {
        return _id;
    }
    public void set_id(int _id) {
        this._id = _id;
    }
    public String get_name() {
        return _name;
    }
    public void set_name(String _name) {
        this._name = _name;
    }
    public int get_age() {
        return _age;
    }
    public void set_age(int _age) {
        this._age = _age;
    }
    /* (non-Javadoc)
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return "Person [_id=" + _id + ", _name=" + _name + ", _age=" + _age+ "]";
    }

}

3.添加一个 personservice 类

package com.example.service;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import com.example.bean.Person;

import android.R.integer;
import android.sax.Element;
import android.sax.EndElementListener;
import android.sax.RootElement;
import android.sax.StartElementListener;
import android.util.Log;

public class SaxService {
    
    private   Person p;
    
    public List<Person> readxml(InputStream stream) throws Throwable, SAXException{
        SAXParserFactory factory=SAXParserFactory.newInstance();
        SAXParser  parser=factory.newSAXParser();
        PersonHander dh=new PersonHander();
         parser.parse(stream, dh);
        return  dh.getPersons();
    }
    
    private class PersonHander extends DefaultHandler{
         private List<Person> persons=null;
         /**
         * @return the persons
         */
        public List<Person> getPersons() {
            return persons;
        }

        
        // 读取顺序
        // startDocument()  startElement()  characters(), endElement(), endDocument()
        
        private String pretag=null;
         private Person p=null;
        /* (non-Javadoc)
         * @see org.xml.sax.helpers.DefaultHandler#startDocument()
         */
        @Override
        public void startDocument() throws SAXException {
            persons =new ArrayList<Person>();
        }
        
        /* (non-Javadoc)
         * @see org.xml.sax.helpers.DefaultHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
         */
        @Override
        public void startElement(String uri, String localName, String qName,
                Attributes attributes) throws SAXException {
            if("person".equals(localName)){
                p=new Person();
             p.set_id( new Integer(attributes.getValue(0)));
            }
            //此步执行完毕后 会执行 characters(char[] ch, int start, int length)
            pretag=localName; //添加一个表示
        }
        
        
        /* (non-Javadoc)
         * @see org.xml.sax.helpers.DefaultHandler#characters(char[], int, int)
         */
        @Override
        public void characters(char[] ch, int start, int length)
                throws SAXException {
         if(pretag!=null)
         {
             String data=new String(ch, start, length);
             if("name".equals(pretag)){
                 p.set_name(data);
             }else if("age".equals(pretag)){
                 p.set_age(new Integer(data));
             }
         }
         //继续执行  endElement(String uri, String localName, String qName)
        }

        /* (non-Javadoc)
         * @see org.xml.sax.helpers.DefaultHandler#endElement(java.lang.String, java.lang.String, java.lang.String)
         */
        @Override
        public void endElement(String uri, String localName, String qName)
                throws SAXException {
            if("person".equals(localName)){
                persons.add(p);
                p=null; 
            }
            
            pretag=null;
            // 清空数据,(多条记录)重复开始执行 startElement(String uri, String localName, String qName,
         }
    }
}

4.进行单元测试

persontest

package com.example.unit;

import java.io.InputStream;
import java.util.List;

import org.xml.sax.SAXException;

import android.test.AndroidTestCase;
import android.util.Log;

import com.example.bean.Person;
import com.example.service.SaxService;

public class persontest  extends AndroidTestCase{
    public void test() throws Throwable, Throwable
    {
        SaxService ss=new SaxService();
        InputStream stream= this.getClass().getClassLoader().getResourceAsStream("Person.xml");
        List<Person> P=    ss.readxml(stream);
        for(Person p : P){
            Log.i("test",   p.toString());
        }
    }
}

进行单元测试 需要在配置文件中加入两段代码

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.sax_xml"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="15" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <!-- 加入下面这句  -->
         <uses-library android:name="android.test.runner" />
        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" >
            ......
        </activity>
    </application>
       <!-- 加入下面这句  -->
<instrumentation android:name="android.test.InstrumentationTestRunner"
      android:targetPackage="com.example.sax_xml" android:label="Tests for My App" />
</manifest>

运行结果: 

读取成功.

源码:https://files.cnblogs.com/xyong/Sax_Xml.rar