对两个文件进行比较并显示异同之开源解决(显示增加删除)

由于公司项目需要对两个文件进行比较.(其实是数据库文本字段)

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并且显示异同.

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这里不是进行一个简单的比较.有一个文件就是

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text1? 1234

text2?? 012324

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这两个文件并不是一个字段都不同.所以用一个一个 对比的办法是不可能的.因为text2 只是在 text1的基础上

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在首字母上面增加了一个0 其他的没有改变...由于项目紧..没有自己实现..(自己实现也没有什么太好的思路)

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这里就不讨论原理了..

http://www.incava.org/projects/java/java-diff/

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文件下载

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这个是开源的解决方案..在网络上面找到的.分享下.

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实现很简单一共有两个类..两jar包都没有..直接把源文件放到工程下面进行测试..

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demo也是很简单的.

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Object[] a = new Object[] {        "a",        "b",        "c",        "d",        "e"    };    Object[] b = new Object[] {        "a",        "x",        "y",        "b",        "c",        "j",        "e",    };    Difference[] expected = new Difference[] {        new Difference(1, -1,  1,  2),        new Difference(3,  3,  5,  5),    };    Diff diff = new Diff(a, b);    List diffOut = diff.diff();

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要求输入的是一个Object[] 或是一个Collection的接口...

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这个就不说你是怎么将你的文件转换成数组了.

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String strs = "123456";char[] strChars = strs.toCharArray();Object[] objs = new Object[strChars.length];for( int i  = 0; i < strChars.length; i ++){objs[i] = strChars[i];}

?下面看这个代码:

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public static void main(String[] args) {Object[] a = new Object[] { "a", "b", "c", "d", "e" };Object[] b = new Object[] { "a", "x", "y", "b", "c", "j", "e", };Diff diff = new Diff(a, b);List diffOut = diff.diff();for (int i = 0; i < diffOut.size(); i++) {Difference diffce = (Difference) diffOut.get(i);System.out.println(diffce);}}

?在main函数里面运行:

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显示结果:

del: [1,-1] add: [1,2]
del: [3,3] add: [5,5]

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其中difference是显示不同的类下面有4个属性:

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/**     * The point at which the deletion starts.     */    private int delStart = NONE;    /**     * The point at which the deletion ends.     */    private int delEnd = NONE;    /**     * The point at which the addition starts.     */    private int addStart = NONE;    /**     * The point at which the addition ends.     */    private int addEnd = NONE;

?当delEnd 或 addEnd 为 -1 的时候表示不进行操作.

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//abcde//01234//a<add>xy</add>cde//0     12      345//a<add>xy</add>c<del>d</del>e//0     12      3            4//a<add>xy</add>bc<del>d</del><add>j</add>e//0     12      34                 5      6

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图示:<add>表示增加<del>表示删除.

del: [1,-1]? 没有删除 add: [1,2]向a [1]中添加[1][2]
del: [3,3]? 删除a中[3]? add: [5,5] 向a中添加[5]

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[start,end]表示操作的数组下标从0开始.起始结束.

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注:进行了del操作.数组长度减少.添加数组长度增加.

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其中你自己调用.delStart,delEnd , addStart,addEnd就可以对数组进行标示了....

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如果代码中的<add>换成其他的<b>标签就可以在html中.显示文件的不同了.

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public static void main(String[] args) {Object[] a = new Object[] { "a", "b", "c", "d", "e" };Object[] b = new Object[] { "a", "x", "y", "b", "c", "j", "e" };Diff diff = new Diff(a, b);List diffOut = diff.diff();for (int i = 0; i < diffOut.size(); i++) {Difference diffce = (Difference) diffOut.get(i);System.out.println(diffce);}// abcde// 01234// a<add>xy</add>cde// 0 12 345// a<add>xy</add>c<del>d</del>e// 0 12 3 4// a<add>xy</add>bc<del>d</del><add>j</add>e// 0 12 34 5 6ArrayList list = new ArrayList();for (int i = 0; i < a.length; i++) {list.add(a[i]);}for (int i = 0; i < diffOut.size(); i++) {Difference tempDiff = (Difference) diffOut.get(i);int delStart = tempDiff.getDeletedStart();int delEnd = tempDiff.getDeletedEnd();int addStart = tempDiff.getAddedStart();int addEnd = tempDiff.getAddedEnd();if (delEnd != -1) {// delEnd == -1 就是不进行除...// 删除开始.for (int j = delStart; j <= delEnd; j++) {// 删除多个.list.remove(j);if (delStart != 0) {String temp = list.get(delStart - 1).toString();list.remove(delStart - 1);list.add(delStart - 1, temp + "<del>" + b[j]+ "</del>");} else {String temp = list.get(0).toString();list.remove(0);list.add(0, temp + "<del>" + b[j] + "</del>");}pirntList(list);}}if (addEnd != -1) {// addEnd == -1 就是不进行添加...// 下面添加的情况..for (int j = addStart; j <= addEnd; j++) {// 添加多个.if (addStart > list.size()) {list.add("<add>" + b[j] + "</add>");} else {list.add(addStart, "<add>" + b[j] + "</add>");}pirntList(list);}}}pirntList(list);// return buffer.toString();}public static void pirntList(List list) {StringBuffer buffer = new StringBuffer();for (int i = 0; i < list.size(); i++) {buffer.append(""+list.get(i));}System.out.println(buffer.toString());}

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通过ArrayList 实现对数据的整理.用remove 删除.用add(index,object)进行添加.

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结果:

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del: [1,-1] add: [1,2]
del: [3,3] add: [5,5]
a<add>x</add>bcde
a<add>y</add><add>x</add>bcde
a<add>y</add><add>x</add><del>b</del>cde
a<add>y</add><add>x</add><del>b</del>cd<add>j</add>e
a<add>y</add><add>x</add><del>b</del>cd<add>j</add>e

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最后显示了a变成b的全部过程.

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1 楼 xifanlou 2008-10-23 巧了，我也在做一个数据库数据比较的测试用例，刚好可以用到，谢谢了 2 楼 xifanlou 2008-10-23 巧了，我也在做一个数据库数据比较的测试用例，刚好可以用到，谢谢了