第二周第四天(解析/过滤文件/找d盘里的所有txt文件/FileInputStream/FileOutputStream/拷贝文件/readLine读取一个文本行/在一个文档里写入内容)

过滤文件

[code]package com.day4_2015_7_23;
import java.io.File;
public class Test {
public static void main(String[] args) {
    ergodicFile("d:\\");
}
    public static void ergodicFile(String filePath){
    File file = new File(filePath);
    //public File(String pathname)通过将给定路径名字符串转换为抽象路径名来创建一个新 File 实例
    File[] files = file.listFiles();//file.listFiles() 返回一个抽象路径名数组，
    //这些路径名表示此抽象路径名表示的目录中的文件。
    for (int i = 0; i < files.length; i++) {
        if(files[i].isDirectory()){
            //files[i].isDirectory()测试此抽象路径名表示的文件是否是一个目录。
            ergodicFile(files[i].getAbsolutePath());
            //files[i].getAbsolutePath()返回此抽象路径名的绝对路径名字符串。
        }else{
            if(files[i].getName().endsWith(".zip")){
                System.out.println(files[i].getAbsolutePath());
            }
        }

    }

    }
}

找d盘里的所有txt文件

[code]package com.day4_2015_7_23;
import java.io.File;
import java.io.FilenameFilter;
import java.nio.file.Files;
public class ZipFilenameFilter implements FilenameFilter{

    @Override
    public boolean accept(File dir, String name) {
        return name.endsWith(".txt");
    }
}
package com.day4_2015_7_23;
import java.io.File;
public class Test1 {
    public static void main(String[] args) {
    ZipFilenameFilter filter = new ZipFilenameFilter();
    File file = new File("d:\\");
    File[] files = file.listFiles(filter);
    for (int i = 0; i < files.length; i++) {
        System.out.println(files[i].getAbsolutePath());
    }
}
}

FileInputStream

[code]package com.day4_2015_7_23;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class Test2 {
public static void main(String[] args) {
    File file =new File("d:\\11.txt");
    FileInputStream in =null;
    try{
        in = new FileInputStream(file);
        byte[] arry = new byte[1024];
        int i = in.read(arry);
        while(i != -1){
            System.out.println(new String(arry,0,i));
            i=in.read(arry);
            }
    }catch (FileNotFoundException e) {
            // TODO: handle exception
            e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            finally{
                if(in!=null);{
                try {
                    in.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                }
            }

}
}

FileOutputStream

[code]//*************FileOutputStream*************//
package com.day4_2015_7_23;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Scanner;
public class Test3 {
    public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    String s=scanner.next();
    File file =new File("d:\\33.txt");
    if(!file.exists()){
        try {
            file.createNewFile();
        } catch (IOException e) {
            // TODO: handle exception
            e.printStackTrace();
        }
    }
    FileOutputStream out = null;
    try {
        out = new FileOutputStream(file);
        out.write(s.getBytes());
        out.flush();
    } catch (FileNotFoundException e) {
        // TODO: handle exception
    e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    finally{
        if(out!=null);{
        try {
            out.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        }
    }
}
}

拷贝文件

[code]//***********拷贝文件**************//
package com.day4_2015_7_23;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
public class Test4 {
    public static void main(String[] args) {
    copy("d:\\22.txt","d:\\33.txt");
}
//写一个copy的方法
    public static void copy(String path,String copy){
    File source = new File(path);
    File file = new File(copy);
    if(!source.exists()){
        System.out.println("拷贝的源文件不存在");
        return;
    }
    //如果要拷贝的文件不存在就新建一个文件
    if(!file.exists()){
        try{
            file.createNewFile();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
    try {
        FileInputStream sourceIn = new FileInputStream(source);
        FileOutputStream copyOut = new FileOutputStream(copy);
        byte[] array = new byte[1024];
        int i = 0;
        while(i !=-1){
            i = sourceIn.read(array);
            if(i!=-1){
                copyOut.write(array,0,i);

            }
        }
        sourceIn.close();
        copyOut.flush();
        copyOut.close();
    } catch (FileNotFoundException e) {
        // TODO: handle exception
        e.printStackTrace();
    }catch(IOException e){
        e.printStackTrace();
    }
} 
}

readLine读取一个文本行

[code]//***********readLine读取一个文本行*************//
package com.day4_2015_7_23;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
public class Test5 {
    public static void main(String[] args) {
        File file = new File("d:\\22.txt");
        try {
            FileInputStream is = new FileInputStream(file);
            InputStreamReader read = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(read);
            String s = br.readLine();
            while(s!=null){
                System.out.println(s);
                s=br.readLine();
            }
            br.close();
            read.close();
            is.close();
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                  e.printStackTrace();
            }catch(IOException e){
                e.printStackTrace();
            }
    }
    }

在一个文档里写入内容

[code]//*********在一个文档里写入内容**********//
package com.day4_2015_7_23;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
public class Test6 {
    public static void main(String[] args) {
        File file = new File("d:\\22.txt");
        try {
            FileOutputStream os = new FileOutputStream(file);
            OutputStreamWriter writer = new OutputStreamWriter(os);
            BufferedWriter bw = new BufferedWriter(writer);
            bw.write("你好");
            bw.newLine();
            bw.write("你好");
            bw.flush();
            writer.flush();
            os.flush();
            bw.close();
            writer.close();
            os.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

修改文档内容

[code]///*******修改文档内容*****//
package com.day4_2015_7_23;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintStream;
public class Test7 {
public static void main(String[] args) {
    File file = new File("d:\\11.txt");
    try {
        PrintStream ps = new PrintStream(file);
        System.setOut(ps);
        System.out.println("你好啊");
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}
}

DOM解析

[code]package com.day4_2015_7_23;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class Test8 {
    public static void main(String[] args) {
    // 创建DOM解析器的工厂
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        try {
            // 从DOM工厂获得DOM 解析器
            DocumentBuilder db = dbf.newDocumentBuilder();
            // 解析XML文档，得到一个Document,即DOM树
            Document doc = db.parse("xml.xml");
            // 得到所有的pet节点列表信息/得到文档中的所有weather标签
            NodeList list = doc.getElementsByTagName("Weather");
            // 轮循xml信息
            for (int i = 0; i < list.getLength(); i++) {
                Node node = list.item(i);
                // node.getFirstChild()得到weather标签的第一个子标签city
                // node1.getNextSibling()得到city标签的下一个子标签
                for (Node node1 = node.getFirstChild(); node1 != null; node1 = node1.getNextSibling())
                    if (node1.getNodeType() == node1.ELEMENT_NODE) {// 判断节点类型是ELEMENT_NODE
                        if (node1.getFirstChild() != null) {// 得到该节点的第一个子节点不能为空
                            System.out.println(node1.getFirstChild().getNodeValue());
                        }
                    }
            }
        } catch (ParserConfigurationException e) {

            e.printStackTrace();
        } catch (SAXException e) {

            e.printStackTrace();
        } catch (IOException e) {

            e.printStackTrace();
        }
    }
}

重写SAXException的一些方法，然后解析文件

[code]package com.day4_2015_7_23;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class MySAXHandler extends DefaultHandler {

    @Override
    public void startDocument() throws SAXException {
        // TODO Auto-generated method stub
        super.startDocument();
        System.out.println("开始解析");
    }

    @Override
    public void endDocument() throws SAXException {
        // TODO Auto-generated method stub
        super.endDocument();
        System.out.println("解析结束");
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        // TODO Auto-generated method stub
        super.startElement(uri, localName, qName, attributes);
        System.out.println("开始标签"+qName);
        if(qName.equals("Weather")){
            System.out.println("Attributes"+attributes.getValue("name"));
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        // TODO Auto-generated method stub
        super.endElement(uri, localName, qName);
        System.out.println("结束标签"+qName);
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        // TODO Auto-generated method stub
        super.characters(ch, start, length);
        System.out.println("标签内容"+new String(ch,start,length));
    }

}
package com.day4_2015_7_23;
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.SAXException;
public class Test9 {
    public static void main(String[] args) {
    SAXParserFactory factory= SAXParserFactory.newInstance();
    File f = new File("d:\\xml.xml");
       try {
            SAXParser parser = factory.newSAXParser();
            MySAXHandler handler = new MySAXHandler();
            parser.parse(f, handler);
        }catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    } 
}