git diff命令

1.作用：

git diff用来显示我们对文件做了何种更改

注意:git diff查看的是还没有暂存起来的改动，而不是这次工作和上次提交之间的差异（因为可能你已经暂存过，之后又对文件进行了更改，diff显示的是这些改动）

git diff --cached 是查看已经暂存起来的变化

 

2.用法:

首先我们可以执行git status查看修改过的文件，可以看到有两个文件被修改

git status

On branch master
Your branch is ahead of 'origin/master' by 1 commit.
  (use "git push" to publish your local commits)

Changes not staged for commit:
  (use "git add ..." to update what will be committed)
  (use "git checkout -- ..." to discard changes in working directory)

        modified:   src/thinkinjava/chapter20_annotations/UseCase.java
        modified:   src/thinkinjava/chapter20_annotations/UseCaseTracker.java

Untracked files:
  (use "git add ..." to include in what will be committed)

        OSS/
        PRD/
        test/

no changes added to commit (use "git add" and/or "git commit -a")

执行git diff可以查看所有的未暂存的修改

git diff

warning: LF will be replaced by CRLF in src/thinkinjava/chapter20_annotations/UseCase.java.
The file will have its original line endings in your working directory
warning: LF will be replaced by CRLF in src/thinkinjava/chapter20_annotations/UseCaseTracker.java.
The file will have its original line endings in your working directory
diff --git a/src/thinkinjava/chapter20_annotations/UseCase.java b/src/thinkinjava/chapter20_annotations/UseCase.java
index 672c5da..82475d3 100644
--- a/src/thinkinjava/chapter20_annotations/UseCase.java
+++ b/src/thinkinjava/chapter20_annotations/UseCase.java
@@ -15,5 +15,5 @@ import java.lang.annotation.Target;
 @Retention(RetentionPolicy.RUNTIME)
 public @interface UseCase {
     public int id();
-    public String description() default "no description";
+    public String description() default "no descriptions";
 }
diff --git a/src/thinkinjava/chapter20_annotations/UseCaseTracker.java b/src/thinkinjava/chapter20_annotations/UseCaseTracker.java
index ce0e229..750ad74 100644
--- a/src/thinkinjava/chapter20_annotations/UseCaseTracker.java
+++ b/src/thinkinjava/chapter20_annotations/UseCaseTracker.java
@@ -19,7 +19,7 @@ public class UseCaseTracker {
   }
   public static void main(String[] args) {
     List useCases = new ArrayList();
-    Collections.addAll(useCases, 47, 48, 49, 50);
+    Collections.addAll(useCases, 47, 48, 49);
     trackUseCases(useCases, PasswordUtils.class);
   }
 } /* Output:

要是想查看某个文件的修改 可以执行git diff [<文件路径>]

git diff src/thinkinjava/chapter20_annotations/UseCase.java

warning: LF will be replaced by CRLF in src/thinkinjava/chapter20_annotations/UseCase.java.
The file will have its original line endings in your working directory
diff --git a/src/thinkinjava/chapter20_annotations/UseCase.java b/src/thinkinjava/chapter20_annotations/UseCase.java
index 672c5da..82475d3 100644
--- a/src/thinkinjava/chapter20_annotations/UseCase.java
+++ b/src/thinkinjava/chapter20_annotations/UseCase.java
@@ -15,5 +15,5 @@ import java.lang.annotation.Target;
 @Retention(RetentionPolicy.RUNTIME)
 public @interface UseCase {
     public int id();
-    public String description() default "no description";
+    public String description() default "no descriptions";
 }

如果已经通过git add命令将文件暂存,则需要通过git diff --cached查看

git diff --cached

diff --git a/src/thinkinjava/chapter20_annotations/UseCase.java b/src/thinkinjava/chapter20_annotations/UseCase.java
index 672c5da..82475d3 100644
--- a/src/thinkinjava/chapter20_annotations/UseCase.java
+++ b/src/thinkinjava/chapter20_annotations/UseCase.java
@@ -15,5 +15,5 @@ import java.lang.annotation.Target;
 @Retention(RetentionPolicy.RUNTIME)
 public @interface UseCase {
     public int id();
-    public String description() default "no description";
+    public String description() default "no descriptions";
 }

 

3.查看两个提交之间的差异

git diff a57d49d3fedefc6ddfb1 37d7375155819c170ffd7e