java 判断两个文件是否相同

使用java 如何判断两个文件是否相同呢？

我的做法是

（1）先比较两个文件内容的长度；

（2）在长度相同的情况下，再比较两个文件的MD5值。

【create md5】按钮用于生成source file的文件内容长度和MD5值。

运行主类：CheckSameApp 

package com.hw.main;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

import com.common.util.SystemUtil;
import com.swing.dialog.DialogUtil;
import com.swing.messagebox.GUIUtil23;

public class CheckSameApp extends JFrame
{
    private static final long serialVersionUID = 1644076682819874235L;
    private JTextField        sourceFileTF;
    private JButton           browserSourceBtn;
    private JTextField        targetFileTF;
    private JButton           createmd5Button  = null;
    private JButton           checkmd5Btn      = null;
    private JButton           browserTargetBtn = null;
    /***
     * MD5 of last file
     */
    private String            result           = null;
    private long              size_of_file     = 0;
    private JButton           compareBtn       = null;
    private File              srcfile          = null;
    private File              targfile         = null;
    protected static String   MESG_DIFF        = "[failed:] they are different";
    protected static String   MESG_SAME        = "[successfully:] they are same completely";

    public static void main(String[] args)
    {
        CheckSameApp app = new CheckSameApp();
        app.launchFrame();
    }

    public void launchFrame()
    {
        this.setTitle("Compare two files by MD5");
        Dimension screensize = Toolkit.getDefaultToolkit().getScreenSize();
        this.setSize(700, 200);
        Dimension framesize = this.getSize();
        int x = (int) screensize.getWidth() / 2 - (int) framesize.getWidth()
            / 2;
        int y = (int) screensize.getHeight() / 2 - (int) framesize.getHeight()
            / 2;
        this.setLocation(x, y);
        Container c = this.getContentPane();
        layout(c);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    /***
     * setting menu
     */
    

    public void layout(Container c)
    {
        //        setMenu2();
        JPanel mainPane = new JPanel();
        GridBagLayout gridBagLayout = new GridBagLayout();
        gridBagLayout.columnWidths = new int[]
        { 20, 80/*between source file and text field*/, 300, 60, 0 };
        gridBagLayout.rowHeights = new int[]
        { 17, 0, 0, 0, 0, 0, 0, 0, 0, 25, 0, 0 };
        gridBagLayout.columnWeights = new double[]
        { 0.0, 0.0, 1.0, 1.0, Double.MIN_VALUE };
        gridBagLayout.rowWeights = new double[]
        { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 1.0,
            Double.MIN_VALUE };

        mainPane.setLayout(gridBagLayout);
        JLabel ftpServerLb = new JLabel("source file");
        GridBagConstraints gbc_setConnectionsLabel = new GridBagConstraints();
        gbc_setConnectionsLabel.anchor = GridBagConstraints.WEST;
        gbc_setConnectionsLabel.insets = new Insets(0, 0, 5, 5);
        gbc_setConnectionsLabel.gridx = 1;
        gbc_setConnectionsLabel.gridy = 1;
        mainPane.add(ftpServerLb, gbc_setConnectionsLabel);
        //        dialog.add(ftpserverTF);

        sourceFileTF = new JTextField();
        if (!SystemUtil.isWindows)
        {
            sourceFileTF.setText("/home/whuang2/bin/ab.txt");
        }
        else
        {
            sourceFileTF.setText("");
        }
        GridBagConstraints gbc_connectionsTF = new GridBagConstraints();
        gbc_connectionsTF.fill = GridBagConstraints.HORIZONTAL;
        gbc_connectionsTF.insets = new Insets(0, 0, 5, 5);
        gbc_connectionsTF.gridx = 2;
        gbc_connectionsTF.gridy = 1;
        mainPane.add(sourceFileTF, gbc_connectionsTF);

        browserSourceBtn = new JButton("browser source");
        GridBagConstraints gbc_browserSourceBtn = new GridBagConstraints();
        gbc_browserSourceBtn.fill = GridBagConstraints.EAST;
        gbc_browserSourceBtn.insets = new Insets(0, 0, 5, 5);
        gbc_browserSourceBtn.gridx = 3;
        gbc_browserSourceBtn.gridy = 1;
        mainPane.add(browserSourceBtn, gbc_browserSourceBtn);
        browserSourceBtn.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                //                System.out.println("source");
                boolean isSuccess = DialogUtil.browser3(sourceFileTF,
                    JFileChooser.FILES_ONLY, CheckSameApp.this);
                //                if (isSuccess)
                //                {
                //                    targetFileTF.setText(SystemUtil.getParentDir(sourceFileTF
                //                            .getText()));
                //                }
            }
        });

        JPanel buttonPane = new JPanel();
        //        buttonPane.setBackground(Color.red);
        GridBagConstraints gbc_buttonPane = new GridBagConstraints();
        gbc_buttonPane.fill = GridBagConstraints.HORIZONTAL;
        gbc_buttonPane.insets = new Insets(0, 0, 5, 5);
        gbc_buttonPane.gridx = 2;
        gbc_buttonPane.gridy = 2;
        mainPane.add(buttonPane, gbc_buttonPane);

        createmd5Button = new JButton("create md5");
        checkmd5Btn = new JButton("check");
        checkmd5Btn.setEnabled(false);
        buttonPane.add(createmd5Button);
        buttonPane.add(checkmd5Btn);
        createmd5Button.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                if (!validate3(true))
                {
                    return;
                }
                sourceFileTF.setEditable(false);
                new Thread(new Runnable()
                {
                    @Override
                    public void run()
                    {
                        createmd5Button.setEnabled(false);
                        size_of_file = srcfile.length();
                        result = SystemUtil.getFileMD5(srcfile);
                        checkmd5Btn.setEnabled(true);
                        createmd5Button.setEnabled(true);
                    }
                }).start();

                
            }
        });

        checkmd5Btn.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                //                if (!validate3(true))
                //                {
                //                    return;
                //                }
                long size_of_file2 = srcfile.length();
                if (size_of_file2 != size_of_file)
                {
                    System.out.println("by size");
                    GUIUtil23.errorDialog(MESG_DIFF);
                    return;
                }

                new Thread(new Runnable()
                {
                    @Override
                    public void run()
                    {
                        checkmd5Btn.setEnabled(false);
                        String result2;
                        sourceFileTF.setEditable(true);
                        result2 = SystemUtil.getFileMD5(srcfile);
                        boolean isSame2=isSame(result2, result);
                        checkmd5Btn.setEnabled(true);
                        if (isSame2)
                        {
                            GUIUtil23.infoDialog(MESG_SAME);
                        }
                        else
                        {
                            GUIUtil23.errorDialog(MESG_DIFF);
                        }
                    }
                }).start();
                
            }
        });

        JLabel targetLabel = new JLabel("target file");
        GridBagConstraints gbc_driveClassLabel = new GridBagConstraints();
        gbc_driveClassLabel.anchor = GridBagConstraints.WEST;
        gbc_driveClassLabel.insets = new Insets(0, 0, 5, 5);
        gbc_driveClassLabel.gridx = 1;
        gbc_driveClassLabel.gridy = 3;
        mainPane.add(targetLabel, gbc_driveClassLabel);

        targetFileTF = new JTextField();
        if (!SystemUtil.isWindows)
        {
            targetFileTF.setText("/home/whuang2/bin/wh_dos2unix");
        }
        GridBagConstraints gbc_driveClassTF = new GridBagConstraints();
        gbc_driveClassTF.insets = new Insets(0, 0, 5, 5);
        gbc_driveClassTF.fill = GridBagConstraints.HORIZONTAL;
        gbc_driveClassTF.gridx = 2;
        gbc_driveClassTF.gridy = 3;
        mainPane.add(targetFileTF, gbc_driveClassTF);
        targetFileTF.setColumns(10);

        browserTargetBtn = new JButton("browser target");
        GridBagConstraints gbc_browserTargetBtn = new GridBagConstraints();
        gbc_browserTargetBtn.fill = GridBagConstraints.EAST;
        gbc_browserTargetBtn.insets = new Insets(0, 0, 5, 5);
        gbc_browserTargetBtn.gridx = 3;
        gbc_browserTargetBtn.gridy = 3;
        mainPane.add(browserTargetBtn, gbc_browserTargetBtn);
        browserTargetBtn.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                //                System.out.println("target");
                DialogUtil.browser3(targetFileTF,
                    JFileChooser.FILES_AND_DIRECTORIES, CheckSameApp.this);
            }
        });
        compareBtn = new JButton("compare");
        GridBagConstraints gbc_runBtn = new GridBagConstraints();
        gbc_runBtn.fill = GridBagConstraints.EAST;
        gbc_runBtn.insets = new Insets(0, 0, 5, 5);
        gbc_runBtn.gridx = 4;
        gbc_runBtn.gridy = 3;
        mainPane.add(compareBtn, gbc_runBtn);

        compareBtn.addActionListener(new ActionListener()
        {

            @Override
            public void actionPerformed(ActionEvent e)
            {
                if (!validate3(false))
                {
                    return;
                }

                long size_of_targfile = targfile.length();
                long size_of_srcfile = srcfile.length();
                if (size_of_targfile != size_of_srcfile)
                {
                    System.out.println("by size");
                    GUIUtil23.errorDialog(MESG_DIFF);
                    return;
                }
                new Thread(new Runnable()
                {
                    @Override
                    public void run()
                    {
                        compareBtn.setEnabled(false);
                        String result_source = SystemUtil.getFileMD5(srcfile);
                        String result_target;
                        result_target = SystemUtil.getFileMD5(targfile);
                        boolean isSame2=isSame(result_source, result_target);
                        compareBtn.setEnabled(true);
                        if (isSame2)
                        {
                            GUIUtil23.infoDialog(MESG_SAME);
                        }
                        else
                        {
                            GUIUtil23.errorDialog(MESG_DIFF);
                        }

                    }
                }).start();
            }
        });

        c.add(mainPane, BorderLayout.CENTER);
        //        System.out.println(c.getLayout());
        //new JScrollPane(text)
    }

    //    private String create_md5(String filePath)
    //    {
    //        try
    //        {
    //            return create_md5(filePath, null);
    //        }
    //        catch (IOException e)
    //        {
    //            e.printStackTrace();
    //        }
    //        return null;
    //    }

    /***
     * 
     * @param result_source : such as b79898bb7907648871745cd5422c79ce   /home/whuang2/bin/ab.txt
     * @param result_target
     * @return
     */
    private boolean isSame(String result_source, String result_target)
    {
        if (result_source == null || result_target == null)
        {
            return false;
        }
        return (result_source.split("[ \t]")[0].equals(result_target
                .split("[ \t]")[0]));
    }


    private boolean validate3(boolean isSelf)
    {
        String sourceFile = sourceFileTF.getText();
        String targetFile_dir = targetFileTF.getText();
        if (sourceFile == null || sourceFile.equals(""))
        {
            GUIUtil23
                    .warningDialog("source file can not be empty,please select again  !");
            sourceFileTF.requestFocus();//focus

            return false;
        }
        if (!isSelf)
        {
            if (targetFile_dir == null || targetFile_dir.equals(""))
            {
                GUIUtil23
                        .warningDialog("target file can not be empty,please select again !");
                targetFileTF.requestFocus();//focus
                return false;
            }
        }
        //                System.out.println("source file:" + sourceFile);
        //                System.out.println("target file:" + targetFile_dir);
        srcfile = new File(sourceFile);
        if (!srcfile.exists())
        {
            GUIUtil23
                    .warningDialog("source file does not exist,please select again!");
            sourceFileTF.requestFocus();//focus
            sourceFileTF.selectAll();
            return false;
        }
        if (srcfile.exists() && srcfile.isDirectory())
        {
            GUIUtil23
                    .warningDialog("source file can not be directory,please select again!");
            sourceFileTF.requestFocus();//focus
            sourceFileTF.selectAll();
            return false;
        }
        if (!isSelf)
        {
            {
                targfile = new File(targetFile_dir);
                if (!targfile.exists())
                {
                    GUIUtil23
                            .warningDialog("target file does not exist,please select again!");
                    targetFileTF.requestFocus();//focus
                    targetFileTF.selectAll();
                    return false;
                }
                if (targfile.exists() && targfile.isDirectory())
                {
                    GUIUtil23
                            .warningDialog("target file can not be directory,please select again!");
                    targetFileTF.requestFocus();//focus
                    targetFileTF.selectAll();
                    return false;
                }
            }
        }
        return true;

    }

    //    public static void main2(String[] args)
    //    {
    //        String sourceFile = "/home/whuag2/workspace/io0007-find_progess/src/com/cmd/dos/hw/util/CMDUtil.java";
    //        md5(sourceFile);
    //    }

}

 swingwork类：CheckSameSwingWorker

package com.hw.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.List;

import javax.swing.SwingWorker;

import com.common.util.MyProcess;

public class CheckSameSwingWorker extends SwingWorker<Boolean, Character>
{
    private BufferedReader br_right       = null;
    private BufferedReader br_error       = null;
    private MyProcess      myprocess      = null;
    private char           word           = ' ';
    private int            tmp            = 0;
    private boolean        isPrintVerbose = false;
    private StringBuffer   stringbuf      = new StringBuffer();

    public CheckSameSwingWorker(MyProcess myprocess, BufferedReader br)
    {
        this.br_right = br;
        this.myprocess = myprocess;

    }

    public CheckSameSwingWorker(MyProcess myprocess)
    {
        this.myprocess = myprocess;
        br_right = new BufferedReader(new InputStreamReader(
            myprocess.getInputStream()), 4096);
        br_error = new BufferedReader(new InputStreamReader(
            myprocess.getErrorStream()), 4096);
    }

    @Override
    protected Boolean doInBackground() throws Exception
    {
        while ((tmp = br_right.read()) != -1)
        {
            word = (char) tmp;
            publish(word);
        }
        while ((tmp = br_error.read()) != -1)
        {
            word = (char) tmp;
            publish(word);
        }
        if (isPrintVerbose)
        {
            System.out.println("doInBackground() over");
        }
        return true;
    }

    @Override
    protected void process(List<Character> chunks)
    {
        for (char temp : chunks)
        {
            {
//                System.out.print(temp);
                this.stringbuf.append(temp);
            }
        }
    }

    public StringBuffer getStringbuf()
    {
        return stringbuf;
    }

    /***
     * main thread can't execute next command(below waitFor()) 
     * until done() is executed
     */
    @Override
    protected void done()
    {
        if (isPrintVerbose)
        {
            System.out.println("done() is finish");
        }
        try
        {
            br_right.close();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        this.myprocess.stopLoop();
    }

}

 

依赖的jar是io0007-find_progess.jar

在附件中。