注意：
1.制作xml文件时候特别小心回车和Tab键，在解析程序，把他们也当做是有效字符，因此输出结果会跟预期不一样.
2.在从网上下载文件时读入文件流时候，需要添加StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
要不然下载文件会报错，下载文件失败。这个函数要求在API 9以上才可以使用，因此注意需要在AndroidManifest中配置
<uses-sdk android:minSdkVersion="9" android:targetSdkVersion="18" />
android:minSdkVersion要在9以上，如果为8，则系统将报错，无法编译。
3. 使笔记本调试Eclipse程序，有时候很多快捷键用不了是因为Eclipse很多快捷键跟笔记本的快捷键冲突，而系统优先系统的快捷键。加入一个外插键盘，eclipse快捷键就都能用了。
（1）AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.xml" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="9" android:targetSdkVersion="18" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="com.example.xml.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> </manifest>
(2)FileUtils.java
package com.example.utils;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.os.Environment;
public class FileUtils {
private String SDPATH;
public String getSDPATH() {
return SDPATH;
}
public FileUtils() {
SDPATH = Environment.getExternalStorageDirectory() + "/";
}
public File createSDFile(String fileName) throws IOException {
File file = new File(SDPATH + fileName);
file.createNewFile();
return file;
}
public File createSDDir(String dirName) {
File dir = new File(SDPATH + dirName);
dir.mkdir();
return dir;
}
public boolean isFileExist(String strFileName) {
File file = new File(SDPATH + strFileName);
return file.exists();
}
public File write2SDFromInput(String path, String fileName,
InputStream input) {
File file = null;
OutputStream output = null;
try {
createSDDir(path);
file = createSDFile(path + fileName);
output = new FileOutputStream(file);
byte buffer[] = new byte[4 * 1024];
while ((input.read(buffer)) != -1) {
output.write(buffer);
}
output.flush();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
output.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return file;
}
}(3)HttpDownloader.java
package com.example.utils;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.os.StrictMode;
public class HttpDownloader {
private URL url = null;
public String download(String strUrl){
StringBuffer sb = new StringBuffer();
String line = null;
BufferedReader buffer = null;
try{
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
url = new URL(strUrl);
HttpURLConnection urlConn = (HttpURLConnection)url.openConnection();
buffer = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));
while ((line = buffer.readLine()) != null){
sb.append(line);
}
}catch (Exception e){
e.printStackTrace();
}finally{
try{
buffer.close();
}catch (Exception e){
e.printStackTrace();
}
}
return sb.toString();
}
/**
*
* @param strUrl
* @param strPath
* @param strFileName
* @return
* * -1: error occurs when downloading; 0: downloaded successfully; 1: the downloading file already exists
*/
public int downFile(String strUrl, String strPath, String strFileName){
InputStream inputStream = null;
try{
FileUtils fileUtils = new FileUtils();
if (fileUtils.isFileExist(strPath + strFileName)){
return 1;
} else {
inputStream = getInputStreamFromUrl(strUrl);
File resultFile = fileUtils.write2SDFromInput(strPath, strFileName, inputStream);
if (resultFile == null){
return -1;
}
}
}
catch (Exception e){
e.printStackTrace();
return -1;
}
finally{
try {
inputStream.close();
}
catch (Exception e){
e.printStackTrace();
}
}
return 0;
}
public InputStream getInputStreamFromUrl(String strUrl) throws MalformedURLException, IOException{
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
url = new URL(strUrl);
HttpURLConnection urlConn = (HttpURLConnection)url.openConnection();
InputStream inputStream = urlConn.getInputStream();
return inputStream;
}
}(4)MainActivity.java
package com.example.xml;
import java.io.StringReader;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import com.example.utils.HttpDownloader;
public class MainActivity extends Activity {
private Button parseXML = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
parseXML = (Button)findViewById(R.id.parseXML);
parseXML.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
HttpDownloader hd = new HttpDownloader();
String strResult = hd.download("http://10.0.2.2:8080/examples/test.xml");
System.out.println(strResult);
try {
//使用Simple API for XML (SAX) 读取文件
//相对于DOM一次性按节点模式全读入内存，才能进行处理
//该类为边读边处理，读取操作可以随时中断，适合于超大型的xml文件
SAXParserFactory factory = SAXParserFactory.newInstance();
XMLReader reader = factory.newSAXParser().getXMLReader();
reader.setContentHandler(new MyContentHandler());
reader.parse(new InputSource(new StringReader(strResult)));
}
catch (Exception e) {
e.printStackTrace();
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}(5)MyContentHandler.java
package com.example.xml;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
//这里没有实现contentHandler接口是因为我们不需要重写所有接口函数
//我们采用继承模式，只需将需要重新的函数实现即可
public class MyContentHandler extends DefaultHandler{
String name1, address1, money1, sex1, status1;
String tagName;
/* (non-Javadoc)
* @see org.xml.sax.helpers.DefaultHandler#characters(char[], int, int)
*/
@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
// TODO Auto-generated method stub
if (tagName.equals("name")) {
name1 = new String(ch, start, length);
}
if (tagName.equals("sex")) {
sex1 = new String(ch, start, length);
}
if (tagName.equals("status")) {
status1 = new String(ch, start, length);
}
if (tagName.equals("address")) {
address1 = new String(ch, start, length);
}
if (tagName.equals("money")) {
money1 = new String(ch, start, length);
}
}
/* (non-Javadoc)
* @see org.xml.sax.helpers.DefaultHandler#endDocument()
*/
@Override
public void endDocument() throws SAXException {
// TODO Auto-generated method stub
System.out.println("-----------end----------");
}
/* (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 {
// TODO Auto-generated method stub
if (localName.equals("worker")) {
this.printOut();
}
}
//之所以打印不来这些名称值，是因为在xml中存在"\t"这种符号
//需要对文件重新进行整理
public void printOut() {
System.out.println("name: " + name1);
System.out.println("sex: " + sex1);
System.out.println("status: " + status1);
System.out.println("address: " + address1);
System.out.println("money: " + money1);
}
/* (non-Javadoc)
* @see org.xml.sax.helpers.DefaultHandler#startDocument()
*/
@Override
public void startDocument() throws SAXException {
// TODO Auto-generated method stub
System.out.println("------------begin-----------------");
}
/* (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 {
// TODO Auto-generated method stub
tagName = localName;
if (localName.equals("worker")) {
for (int i = 0; i < attributes.getLength(); i++) {
System.out.println(attributes.getLocalName(i) + "=" + attributes.getValue(i));
}
}
}
}
随时随地看视频
