Commons_IO_FileUtils的使用

commos_io.jar包下载地址：http://commons.apache.org/proper/commons-io/download_io.cgi

官方文档地址：http://commons.apache.org/proper/commons-io/javadocs/api-release/index.html

---

//文件、目录遍历 

1 package commosIO;

import java.io.File;
import java.util.Collection;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.filefilter.DirectoryFileFilter;
import org.apache.commons.io.filefilter.EmptyFileFilter;
import org.apache.commons.io.filefilter.FileFilterUtils;
import org.apache.commons.io.filefilter.SuffixFileFilter;

public class CommosIOTest1 {
    public static void main(String[] args) {
        //文件或目录的大小
        long len = FileUtils.sizeOf(new File("src/commosIO/CommosIOTest1.java"));
        long len2 = FileUtils.sizeOf(new File("F:/EclipseWorkspace/Java300"));
        System.out.println(len);
        System.out.println(len2);
        System.out.println("-----------------------------");
        
        //列出目录下的文件  具体查看api文档
        Collection<File> c = FileUtils.listFiles(new File("F:/EclipseWorkspace/Java300"), 
                EmptyFileFilter.NOT_EMPTY,DirectoryFileFilter.INSTANCE);
        for(File temp:c) {
            System.out.println(temp.getAbsolutePath());
        }
        
        //只列出后缀为java的文件  文件过滤
        System.out.println("-----------------------------");
        Collection<File> c2 = FileUtils.listFiles(new File("F:/EclipseWorkspace/Java300"), 
                new SuffixFileFilter(".java"),DirectoryFileFilter.INSTANCE);
        for(File temp:c2) {
            System.out.println(temp.getAbsolutePath());
        }
        
        System.out.println("-----------------------------");
        Collection<File> c3 = FileUtils.listFiles(new File("F:/EclipseWorkspace/Java300"), 
                FileFilterUtils.or(new SuffixFileFilter(".java"),new SuffixFileFilter(".txt")),
                    DirectoryFileFilter.INSTANCE);
        for(File temp:c3) {
            System.out.println(temp.getAbsolutePath());
        }
    }
}

输出：

---

1659
6089568
-----------------------------
F:EclipseWorkspaceJava300.classpath
F:EclipseWorkspaceJava300.project
F:EclipseWorkspaceJava300.settingsorg.eclipse.jdt.core.prefs
F:EclipseWorkspaceJava300a-coyp.jpg
F:EclipseWorkspaceJava300a.jpg
F:EclipseWorkspaceJava300.jpg
F:EclipseWorkspaceJava300incommosIOCommosIOTest1.class
F:EclipseWorkspaceJava300incommosIOCommosIOTest2.class
F:EclipseWorkspaceJava300incommosIOCommosIOTest3.class
F:EclipseWorkspaceJava300inioStudyCoffee.class
F:EclipseWorkspaceJava300inioStudyCopy.class
F:EclipseWorkspaceJava300inioStudyDecorate.class
F:EclipseWorkspaceJava300inioStudyDecorateStudy1.class
F:EclipseWorkspaceJava300inioStudyDirStudy.class
F:EclipseWorkspaceJava300inioStudyDrink.class
F:EclipseWorkspaceJava300inioStudyIOstudy1.class
F:EclipseWorkspaceJava300inioStudyIOstudy2.class
F:EclipseWorkspaceJava300inioStudyIOstudy3.class
F:EclipseWorkspaceJava300inioStudyIOstudy4.class
F:EclipseWorkspaceJava300inioStudyIOstudy5.class
F:EclipseWorkspaceJava300inioStudyIOstudy6.class
F:EclipseWorkspaceJava300inioStudyIOstudy7.class
F:EclipseWorkspaceJava300inioStudyMilk.class
F:EclipseWorkspaceJava300inioStudySugar.class
F:EclipseWorkspaceJava300in	eststringTestArrayCopy1.class
F:EclipseWorkspaceJava300in	eststringTestMyArrayList.class
F:EclipseWorkspaceJava300in	eststringTestMyHashMap.class
F:EclipseWorkspaceJava300in	eststringTestNode.class
F:EclipseWorkspaceJava300in	eststringTestTestBubbleSort.class
F:EclipseWorkspaceJava300in	eststringTestTestCollection.class
F:EclipseWorkspaceJava300in	eststringTestTestString.class
F:EclipseWorkspaceJava300commons-io-2.6-sources.jar
F:EclipseWorkspaceJava300commons-io-2.6.jar
F:EclipseWorkspaceJava300order.txt
F:EclipseWorkspaceJava300output.txt
F:EclipseWorkspaceJava300srccommosIOCommosIOTest1.java
F:EclipseWorkspaceJava300srccommosIOCommosIOTest2.java
F:EclipseWorkspaceJava300srccommosIOCommosIOTest3.java
F:EclipseWorkspaceJava300srcioStudyCopy.java
F:EclipseWorkspaceJava300srcioStudyDecorateStudy1.java
F:EclipseWorkspaceJava300srcioStudyDirStudy.java
F:EclipseWorkspaceJava300srcioStudyIOstudy1.java
F:EclipseWorkspaceJava300srcioStudyIOstudy2.java
F:EclipseWorkspaceJava300srcioStudyIOstudy3.java
F:EclipseWorkspaceJava300srcioStudyIOstudy4.java
F:EclipseWorkspaceJava300srcioStudyIOstudy5.java
F:EclipseWorkspaceJava300srcioStudyIOstudy6.java
F:EclipseWorkspaceJava300srcioStudyIOstudy7.java
F:EclipseWorkspaceJava300src	eststringTestArrayCopy1.java
F:EclipseWorkspaceJava300src	eststringTestMyArrayList.java
F:EclipseWorkspaceJava300src	eststringTestMyHashMap.java
F:EclipseWorkspaceJava300src	eststringTestTestBubbleSort.java
F:EclipseWorkspaceJava300src	eststringTestTestCollection.java
F:EclipseWorkspaceJava300src	eststringTestTestString.java
F:EclipseWorkspaceJava300	empa.jpg
F:EclipseWorkspaceJava300	est.txt
F:EclipseWorkspaceJava300	estcopy.txt
-----------------------------
F:EclipseWorkspaceJava300srccommosIOCommosIOTest1.java
F:EclipseWorkspaceJava300srccommosIOCommosIOTest2.java
F:EclipseWorkspaceJava300srccommosIOCommosIOTest3.java
F:EclipseWorkspaceJava300srcioStudyCopy.java
F:EclipseWorkspaceJava300srcioStudyDecorateStudy1.java
F:EclipseWorkspaceJava300srcioStudyDirStudy.java
F:EclipseWorkspaceJava300srcioStudyIOstudy1.java
F:EclipseWorkspaceJava300srcioStudyIOstudy2.java
F:EclipseWorkspaceJava300srcioStudyIOstudy3.java
F:EclipseWorkspaceJava300srcioStudyIOstudy4.java
F:EclipseWorkspaceJava300srcioStudyIOstudy5.java
F:EclipseWorkspaceJava300srcioStudyIOstudy6.java
F:EclipseWorkspaceJava300srcioStudyIOstudy7.java
F:EclipseWorkspaceJava300src	eststringTestArrayCopy1.java
F:EclipseWorkspaceJava300src	eststringTestMyArrayList.java
F:EclipseWorkspaceJava300src	eststringTestMyHashMap.java
F:EclipseWorkspaceJava300src	eststringTestTestBubbleSort.java
F:EclipseWorkspaceJava300src	eststringTestTestCollection.java
F:EclipseWorkspaceJava300src	eststringTestTestString.java
-----------------------------
F:EclipseWorkspaceJava300order.txt
F:EclipseWorkspaceJava300output.txt
F:EclipseWorkspaceJava300srccommosIOCommosIOTest1.java
F:EclipseWorkspaceJava300srccommosIOCommosIOTest2.java
F:EclipseWorkspaceJava300srccommosIOCommosIOTest3.java
F:EclipseWorkspaceJava300srcioStudyCopy.java
F:EclipseWorkspaceJava300srcioStudyDecorateStudy1.java
F:EclipseWorkspaceJava300srcioStudyDirStudy.java
F:EclipseWorkspaceJava300srcioStudyIOstudy1.java
F:EclipseWorkspaceJava300srcioStudyIOstudy2.java
F:EclipseWorkspaceJava300srcioStudyIOstudy3.java
F:EclipseWorkspaceJava300srcioStudyIOstudy4.java
F:EclipseWorkspaceJava300srcioStudyIOstudy5.java
F:EclipseWorkspaceJava300srcioStudyIOstudy6.java
F:EclipseWorkspaceJava300srcioStudyIOstudy7.java
F:EclipseWorkspaceJava300src	eststringTestArrayCopy1.java
F:EclipseWorkspaceJava300src	eststringTestMyArrayList.java
F:EclipseWorkspaceJava300src	eststringTestMyHashMap.java
F:EclipseWorkspaceJava300src	eststringTestTestBubbleSort.java
F:EclipseWorkspaceJava300src	eststringTestTestCollection.java
F:EclipseWorkspaceJava300src	eststringTestTestString.java
F:EclipseWorkspaceJava300	est.txt
F:EclipseWorkspaceJava300	estcopy.txt

---

文件读写

 1 package commosIO;

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.apache.commons.io.FileUtils;

public class CommosIOTest2 {
    public static void main(String[] args) throws IOException {
        //读取文件
        String s = FileUtils.readFileToString(new File("output.txt") , "GBK");
        System.out.println(s);
        System.out.println("-----------------");
        byte[] datas = FileUtils.readFileToByteArray(new File("output.txt"));
        System.out.println(datas.length);
        System.out.println("-----------------");
        //逐行读取
        List<String> list = FileUtils.readLines(new File("output.txt"),"GBK");
        for(String temp:list) {
            System.out.println(temp);
        }
        System.out.println("-----------------");
        //写文件  追加
        FileUtils.write(new File("output.txt"), "锄禾日当午
","GBK");
        FileUtils.write(new File("output.txt"), "汗滴禾下土","GBK",true);
    }
}

输出：

锄禾日当午
汗滴禾下土
-----------------
22
-----------------
锄禾日当午
汗滴禾下土
-----------------

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文件拷贝

 1 package commosIO;

import java.io.File;
import java.io.IOException;
import java.net.URL;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;



public class CommosIOTest3 {
    public static void main(String[] args) throws IOException {
        //复制文件
        FileUtils.copyFile(new File("a.jpg"), new File("a-coyp.jpg"));
        //复制文件到目录
        FileUtils.copyFileToDirectory(new File("a.jpg"), new File("temp"));
        //复制目录到目录
        //复制目录等  查看文档  大同小异
        
        //拷贝url内容
        FileUtils.copyURLToFile(new URL("http://www.baidu.com"), new File("order.txt"));
        
        String datas = IOUtils.toString(new URL("http://www.baidu.com"),"UTF-8");
        System.out.println(datas);
    }
}