java-diff

两个文件如何比较差异?可能会想到有文件比对工具,比如Beyond Compare等
用Java如何做呢?,今天介绍一下java-diff-utils

java-diff-utils 是基于java的一种diff实现
github地址: https://github.com/java-diff-utils/java-diff-utils

github 上有一些案例,此处不再赘述.此处只写一种比对两个文件的差异

jar依赖

<dependency>
  <groupId>io.github.java-diff-utils</groupId>
  <artifactId>java-diff-utils</artifactId>
  <version>4.5</version>
</dependency>

 

 

package com.XXXX;

import com.github.difflib.DiffUtils;
import com.github.difflib.algorithm.DiffException;
import com.github.difflib.patch.AbstractDelta;
import com.github.difflib.patch.Chunk;
import com.github.difflib.patch.Patch;
import org.apache.commons.io.IOUtils;

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

class ModuleEventWatcher {
     public static void main(String[] args) throws IOException, DiffException {
         File src = new File("D:/MS/log1.log");
         File target = new File("D:/MS/log2.log");
         List<String> original = IOUtils.readLines(new FileInputStream(src), "UTF-8");
         List<String> revised = IOUtils.readLines(new FileInputStream(target), "UTF-8");
         Patch<String> diff = DiffUtils.diff(original, revised);
         List<AbstractDelta<String>> deltas = diff.getDeltas();
         deltas.forEach(delta -> {
             switch (delta.getType()) {
                 case INSERT:
                     //新增
                     Chunk<String> insert = delta.getTarget();
                     int position = insert.getPosition();
                     System.out.println("+ " + (position + 1) + " " + insert.getLines());
                     break;
                 case CHANGE:
                     //修改
                     Chunk<String> source = delta.getSource();
                     Chunk<String> target1 = delta.getTarget();
                     System.out.println("\n- " + (source.getPosition() + 1) + " " + source.getLines() + "\n+ " + "" + (target1.getPosition() + 1) + " " + target1.getLines());
                     break;
                 case DELETE:
                     //删除
                     Chunk<String> delete = delta.getSource();
                     System.out.println("- " + (delete.getPosition() + 1) + " " + delete.getLines());
                     break;
                 case EQUAL:
//                    System.out.println("无变化");
                     break;
             }
         });
     }
}

运行结果

 

 

• 说明
  DeltaType 共计有四种类型,分别是EQUAL,DELETE,INSERT,CHANGE.含义也很好理解分别为相同,删除,新增,修改

delta.getSource()可以获取源文件的相关信息,delta.getTarget()可以获取目标文件的相关相关信息,返回值均为Chunk<String>,新增时delta.getSource()的信息为空(非null),删除时delta.getTarget()的信息为空(非null)

chunk.getPosition()+1则为行号,chunk.getLines()为对比的文字内容,