java - shell脚本执行中字符串连接错误

Question

这是一个让我困惑了好几天的有线问题。我想通过解析 shell 中的 java 代码文件来获取类的完整类名。我们可以从以下位置获取包名称:

包com.android.mail.ui;

并从代码文件路径获取类名，使用shell命令'basename'。下面是我的 shell 脚本:

#!/bin/bash
get_package_name(){
   java_file=$1
    if [ ! -f $file_path ]; then 
        echo "Sorry,the java file is not exist:$1,please check"
        exit 1
    fi      
    class_base_name=`basename "$java_file" .java`
    echo "class_base_name:$class_base_name"
    package_name=`grep $java_file -e "^package" | awk -F " " '{print $2}' | tr ';' ' ' | sed 's/ //g'`
    echo "package_name get result:$?"
    echo "package_name:$package_name"

方法一，直接使用变量concat

    classpath_name=$package_name.$class_base_name
    echo "method 1 classpath_name:$classpath_name"

方法2，使用sed Replace间接获取concat

    classpath_name2=`echo "aa.bb" | sed "s/aa/$package_name/" | sed "s/bb/$class_base_name/"`
    echo "method 2 classpath_name2:$classpath_name2"

}

The problem is:for some code file the result is ok,like: "class_base_name:MailTransport package_name get result:0 package_name:com.android.email.mail.transport method 1 classpath_name:com.android.email.mail.transport.MailTransport method 2 classpath_name2:com.android.email.mail.transport.MailTransport"

for others it's output is : "class_base_name:EmailApplication package_name get result:0 package_name:com.android.email .EmailApplicationh_name:com.android.email .EmailApplicationh_name2:com.android.email"

the result is totally messing and wrong.I doubt it relates the code content,that really make sense for the result?

Answer 1

发生这种情况是因为您的某些文件使用 Windows 样式 CRLF (\r\n) 行终止符。

这是一个工作示例，一个普通的 Unix 风格 LF (\n) 终止文件:

$ file WorkingFile.java
WorkingFile.java: ASCII text

$ cat -v WorkingFile.java
package foo.bar.baz;

$ get_package_name WorkingFile.java
class_base_name:WorkingFile
package_name get result:0
package_name:foo.bar.baz
method 1 classpath_name:foo.bar.baz.WorkingFile

这是一个失败的示例，带有 CRLF 行终止符:

$ file FailingFile.java
FailingFile.java: ASCII text, with CRLF line terminators

$ cat -v FailingFile.java
package foo.bar.baz;^M        <--- note hidden control char revealed by -v

$ get_package_name FailingFile.java
class_base_name:FailingFile
package_name get result:0
package_name:foo.bar.baz
.FailingFilesspath_name:foo.bar.baz

要修复此问题，您可以使用 tr -d '\r' 删除多余的回车符。我从传统的反引号切换到现代的 $() 以避免反斜杠问题:

package_name=$(grep $java_file -e "^package" | awk -F " " '{print $2}' | tr ';' ' ' | sed 's/ //g' | tr -d '\r')

有关详细信息，请参阅this relevant post .