java IO输入输出流的操作-文件、txt、xml

1、读取目录下指定后缀的文件

public  List<String> readFile(String dirPath) {
       // 建立当前目录中文件的File对象
   		File file = new File(dirPath);
       // 取得代表目录中所有文件的File对象数组
   		File[] list = file.listFiles();
       // 遍历file数组
   		for (int i = 0; i < list.length; i++) {
   			if(list[i].isDirectory()) { 
                   	readFile(list[i].getPath());//递归
             }
   			else{
   				if(list[i].getName().endsWith("htm")){
   					dirPath1.add(list[i].getPath());
   		         }
   			}
   		}
	return dirPath1;
}

2、一行一行的读取文本内容

public  String Reader() throws IOException{
		String temp=null;
		File file=new File("C:\\Users\\Administrator\\Desktop\\tests");
		File[] list=file.listFiles();
		for(int i=0;i<list.length;i++){
                StringBuffer content=new StringBuffer();
                InputStreamReader isr=new InputStreamReader(new                   FileInputStream(list[i].getAbsolutePath()));
                BufferedReader read=new BufferedReader(isr);
	            while((temp=read.readLine())!=null){
				content.append(temp);
				content.append("\n");
				}
		}
		return content.toString();
	}

3、将整个内容写到文本

 public static void FileWrite(String fileName, String content) {   
        FileWriter writer = null;  
        try {     
            // 打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件     
            writer = new FileWriter(fileName, true);    
            writer = new FileWriter(fileName);//不追加文件内容
            writer.write(content);       
        } catch (IOException e) {     
            e.printStackTrace();     
        } finally {     
            try {     
                if(writer != null){  
                    writer.close();     
                }  
            } catch (IOException e) {     
                e.printStackTrace();     
            }     
        }   
    }

4、将字符串内容循环写到文本中  

public String WriteTopic(ArrayList result) throws FileNotFoundException{
		Book book=new Book();
		String id=null;
		String body=null;
		String document=null;
		String qrel=null;
		for(int i=0;i<result.size();i++){
			Pattern p0=Pattern.compile("id=(.*?)bioasq");
			Matcher m0=p0.matcher(result.get(i).toString());
			while(m0.find()){
				id=m0.group(1);
				book.setId(id);
			}
			Pattern p1=Pattern.compile("body:\"(.*?)\"");
			Matcher m1=p1.matcher(result.get(i).toString());
			while(m1.find()){
				body=m1.group(1);
				book.setBody(body);
			}
			Pattern p2=Pattern.compile("\"http://www.ncbi.nlm.nih.gov/pubmed/(.*?)\"");
			Matcher m2=p2.matcher(result.get(i).toString());
			while(m2.find()){
				document=m2.group(1);
	//			book.setDocument(document);
				qrel=id+" "+"0"+" "+document+" "+"1";
				System.out.println(qrel);
				FileOutputStream fos=new FileOutputStream("C:\\Users\\Administrator\\Desktop\\BioASQ_2013_TaskB\\BioASQ_PhaseB.qrel",true);
				PrintStream ps=new PrintStream(fos);
				Scanner in=new Scanner(qrel);
				String s=in.next();
				System.setOut(ps);
		//		System.out.println(s);
			}
		}
		return qrel;
	}

BioASQ_PhaseB.qrel格式

1 0 23220349 1
1 0 19582169 1
1 0 22161322 1
1 0 18025684 1
1 0 15701682 1
1 0 15215406 1
1 0 18081932 1
1 0 18629289 1
1 0 21729286 1
1 0 11438739 1
1 0 10573422 1
2 0 22975810 1
2 0 22852678 1
2 0 22278059 1
2 0 21500720 1
2 0 23331310 1
2 0 23250067 1
2 0 23003992 1
2 0 22714377 1
2 0 22665786 1
2 0 22653729 1
2 0 22330507 1
2 0 22286383 1
2 0 21293374 1
3 0 22921312 1
3 0 22480152 1
3 0 22315491 1
3 0 22258533 1
3 0 21415082 1
3 0 21068339 1
3 0 20569258 1
4 0 23297037 1
4 0 22987359 1
4 0 22540951 1
4 0 22247276 1
......

5、写xml

public void getTopics(String title,String narrative) throws IOException{
		Document document=DocumentHelper.createDocument();
		OutputFormat format=OutputFormat.createPrettyPrint();
		Element root=document.addElement("parameters");
		Element topic=root.addElement("topic");
	   topic.setAttributeValue("id", "1");
	//	topic.setAttributeValue("id",1 );
		Element titleElement=topic.addElement("title");
		Element groupElement=topic.addElement("group");
		Element narrativeElement=topic.addElement("narrative");
		if(title!=null){
		titleElement.setText(title);
		}
		if(narrative!=null){
			narrativeElement.setText(narrative);
		}
		/*File file=new File("/home/zzj/test.topics");
		file.mkdirs();*/
		XMLWriter writer=new XMLWriter(new FileWriter(new File("/home/douban/test.xml")),format);
		writer.write(document);
		writer.flush();
		writer.close();
		
	}

test.xml格式

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

<parameters>
  <topic id="1">
    <title>Give examples of next-generation sequencing applications in mutation screening?</title>
    <group/>
    <narrative>Give examples of next-generation sequencing applications in mutation screening?</narrative>
  </topic>
</parameters>

6、写XML文件,如何在同一个节点下循环加入多个节点

public void WrtierTopics(ArrayList result) throws IOException {
		String body=null;
		Document doc=DocumentHelper.createDocument();
		OutputFormat format=OutputFormat.createPrettyPrint();
		Element root=doc.addElement("parameters");
		for(int i=0;i<result.size();i++){
			Pattern p0=Pattern.compile("id=(.*?)bioasq");
			Matcher m0=p0.matcher(result.get(i).toString());
			Pattern p1=Pattern.compile("body:\"(.*?)\"");
			Matcher m1=p1.matcher(result.get(i).toString());
			if(m1.find()){
				body=m1.group(1);
			}
			Element topic=root.addElement("topic");
			topic.setAttributeValue("id", "1");//topic中的id值固定为1
			Element titleElement=topic.addElement("title");
			Element groupElement=topic.addElement("group");
			Element narrativeElement=topic.addElement("narrative");
			titleElement.setText(body);
			narrativeElement.setText(body);
		}
		XMLWriter writer=new XMLWriter(new FileWriter(new File("C:\\Users\\Administrator\\Desktop\\BioASQ_2013_TaskB\\BioASQ_phaseB.topic")),format);	
		writer.write(doc);
		writer.flush();
		writer.close();
	}

BioASQ_PhaseB.topic格式：

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

<parameters>
  <topic id="1">
    <title>How could we infer functional associations from gene fusion events?</title>
    <group/>
    <narrative>How could we infer functional associations from gene fusion events?</narrative>
  </topic>
  <topic id="1">
    <title>Where is X-ray free electron laser used?</title>
    <group/>
    <narrative>Where is X-ray free electron laser used?</narrative>
  </topic>
  <topic id="1">
    <title>Give examples of next-generation sequencing applications in mutation screening?</title>
    <group/>
    <narrative>Give examples of next-generation sequencing applications in mutation screening?</narrative>
  </topic>
  <topic id="1">
    <title>What are the computational methods for the prediction of beta-barrel transmembrane proteins?</title>
    <group/>
    <narrative>What are the computational methods for the prediction of beta-barrel transmembrane proteins?</narrative>
  </topic>
......
</parameters>