网站开发如何搭建框架,公路建设市场信用信息系统网站,设计之家app,汕头网页网站制作常见的问题是检测并显示两个文本#xff08;尤其是几百行或几千行#xff09;的差异。 使用纯java.lang.String类方法可能是一种解决方案#xff0c;但是对于此类操作最重要的问题是#xff0c;“性能”将不能令人满意。 我们需要一种有效的解决方案#xff0c;其可能具有… 常见的问题是检测并显示两个文本尤其是几百行或几千行的差异。 使用纯java.lang.String类方法可能是一种解决方案但是对于此类操作最重要的问题是“性能”将不能令人满意。 我们需要一种有效的解决方案其可能具有以下观点 文字差异工具示例 该问题包含两个部分 检测两个文本的差异为了检测差异在此解决方案中使用了一种有效的LCS最长公共子序列动态算法 。 该解决方案具有Otext1WordCount * text2WordCount复杂度并在下面被编码为“ longestCommonSubsequence”方法。 可视化差异可视化使用基于HTML标记的方法该方法将text2的新单词标记为绿色将text1的旧单词标记为红色。 该解决方案具有OchangedWordsCount *text1WordCount text2WordCount复杂度并在下面被编码为“ markTextDifferences”方法。 注意1为简单起见“ normalizeText”方法用于删除\ n\ t和多个空格字符。 注意2此类创建为Vaadin组件。 但是“ longestCommonSubsequence”是纯通用的“ markTextDifferences”方法是基于HTML的可视组件的通用因此它们也可以用于不同的框架。 import java.util.ArrayList;
import com.vaadin.ui.CustomComponent;
import com.vaadin.ui.Label;
import com.vaadin.ui.Layout;
import com.vaadin.ui.VerticalLayout;/**
* Text comparison component which marks differences of two texts with colors.
*
* author cb
*/
public class TextCompareComponent extends CustomComponent {private Layout mainLayout new VerticalLayout();private ArrayListString longestCommonSubsequenceList;private static final String INSERT_COLOR #99FFCC;private static final String DELETE_COLOR #CB6D6D;public TextCompareComponent(String text1, String text2) {text1 normalizeText(text1);text2 normalizeText(text2);this.longestCommonSubsequenceList longestCommonSubsequence(text1, text2);String result markTextDifferences(text1, text2, longestCommonSubsequenceList, INSERT_COLOR, DELETE_COLOR);Label label new Label(result, Label.CONTENT_XHTML);mainLayout.addComponent(label);setCompositionRoot(mainLayout);}/*** Finds a list of longest common subsequences (lcs) of given two texts.* * param text1* param text2* return - longest common subsequence list*/private ArrayListString longestCommonSubsequence(String text1,String text2){String[] text1Words text1.split( );String[] text2Words text2.split( );int text1WordCount text1Words.length;int text2WordCount text2Words.length;int[][] solutionMatrix new int[text1WordCount 1][text2WordCount 1];for (int i text1WordCount - 1; i 0; i--) {for (int j text2WordCount - 1; j 0; j--) {if (text1Words[i].equals(text2Words[j])){solutionMatrix[i][j] solutionMatrix[i 1][j 1] 1;}else {solutionMatrix[i][j] Math.max(solutionMatrix[i 1][j],solutionMatrix[i][j 1]);}}}int i 0, j 0;ArrayListString lcsResultList new ArrayListString();while (i text1WordCount j text2WordCount) {if (text1Words[i].equals(text2Words[j])) {lcsResultList.add(text2Words[j]);i;j;} else if (solutionMatrix[i 1][j] solutionMatrix[i][j 1]) {i;}else {j;}}return lcsResultList;}/*** Normalizes given string by deleting \n, \t and extra spaces.* * param text - initial string* return - normalized string*/private String normalizeText(String text) {text text.trim();text text.replace(\n, );text text.replace(\t, );while (text.contains( )) {text text.replace( , );}return text;}/*** Returns colored inserted/deleted text representation of given two texts.* Uses longestCommonSubsequenceList to determine colored sections.** param text1* param text2* param lcsList* param insertColor* param deleteColor* return - colored result text*/private String markTextDifferences(String text1, String text2,ArrayListString lcsList, String insertColor, String deleteColor) {StringBuffer stringBuffer new StringBuffer();if (text1 ! null lcsList ! null) {String[] text1Words text1.split( );String[] text2Words text2.split( );int i 0, j 0, word1LastIndex 0, word2LastIndex 0;for (int k 0; k lcsList.size(); k) {for (i word1LastIndex, j word2LastIndex;i text1Words.length j text2Words.length;) {if (text1Words[i].equals(lcsList.get(k)) text2Words[j].equals(lcsList.get(k))) {stringBuffer.append(SPAN lcsList.get(k) /SPAN);word1LastIndex i 1;word2LastIndex j 1;i text1Words.length;j text2Words.length;}else if (!text1Words[i].equals(lcsList.get(k))) {for (; i text1Words.length !text1Words[i].equals(lcsList.get(k)); i) {stringBuffer.append(SPAN styleBACKGROUND-COLOR: deleteColor text1Words[i] /SPAN);}} else if (!text2Words[j].equals(lcsList.get(k))) {for (; j text2Words.length !text2Words[j].equals(lcsList.get(k)), j) {stringBuffer.append(SPAN styleBACKGROUND-COLOR: insertColor text2Words[j] /SPAN);}}}}for (; word1LastIndex text1Words.length; word1LastIndex) {stringBuffer.append(SPAN styleBACKGROUND-COLOR: deleteColor text1Words[word1LastIndex] /SPAN);}for (; word2LastIndex text2Words.length; word2LastIndex) {stringBuffer.append(SPAN styleBACKGROUND-COLOR: insertColor text2Words[word2LastIndex] /SPAN);}}return stringBuffer.toString();}
} 参考我们的JCG合作伙伴 Cagdas Basaraner在CodeBuild博客上使用LCS方法实现了通用文本比较工具 。 翻译自: https://www.javacodegeeks.com/2012/05/generic-text-comparison-tool-with-lcs.html
