java - 如何使用命令行工具按类名查找导入完整路径？

Question

使用javap，我可以做到这一点:

xb@dnxb:/tmp$ javap 'java.util.Base64'
Compiled from "Base64.java"
public class java.util.Base64 {
  public static java.util.Base64$Encoder getEncoder();
  public static java.util.Base64$Encoder getUrlEncoder();
  public static java.util.Base64$Encoder getMimeEncoder();
  public static java.util.Base64$Encoder getMimeEncoder(int, byte[]);
  public static java.util.Base64$Decoder getDecoder();
  public static java.util.Base64$Decoder getUrlDecoder();
  public static java.util.Base64$Decoder getMimeDecoder();
}
xb@dnxb:/tmp$ 

但是如何在不知道类名位于 java.util.* 下的情况下进行搜索？ (使用命令行实用程序，无需 java 编码)

xb@dnxb:/tmp$ javap 'Base64'
Error: class not found: Base64
xb@dnxb:/tmp$ javap '*.Base64'
Error: class not found: *.Base64
xb@dnxb:/tmp$ javap '*Base64'
Error: class not found: *Base64
xb@dnxb:/tmp$

Answer 1

我发现我可以用这种方式创建我的 map :

xb@dnxb:/tmp$ java -verbose |& grep rt.jar | head -1 #to find out java runtime path
[Opened /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/rt.jar]
xb@dnxb:/tmp$ unzip /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/rt.jar -d /tmp/rt #unzip the rt.jar
   creating: /tmp/rt/META-INF/
 extracting: /tmp/rt/META-INF/MANIFEST.MF  
 extracting: /tmp/rt/com/oracle/net/Sdp$1.class  
 extracting: /tmp/rt/com/oracle/net/Sdp$SdpSocket.class
...
 extracting: /tmp/rt/java/io/Serializable.class  
 extracting: /tmp/rt/java/lang/String.class  
 extracting: /tmp/rt/java/lang/Object.class  
xb@dnxb:/tmp$ 
xb@dnxb:/tmp$ find /tmp/rt > /tmp/rt.map #create list path as map
xb@dnxb:/tmp$ 

，然后 grep (可能更好地将其作为 shell 函数):

xb@dnxb:/tmp$ grep -rni Base64\.class /tmp/rt.map 
1839:/tmp/rt/java/util/Base64.class
2276:/tmp/rt/java/util/prefs/Base64.class
10340:/tmp/rt/com/sun/xml/internal/messaging/saaj/util/Base64.class
13363:/tmp/rt/com/sun/org/apache/xml/internal/security/utils/Base64.class
15044:/tmp/rt/com/sun/org/apache/xerces/internal/impl/dv/xs/Base64BinaryDV$XBase64.class
15096:/tmp/rt/com/sun/org/apache/xerces/internal/impl/dv/util/Base64.class
xb@dnxb:/tmp$ 

请注意，/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/classlist 仅包含约 2559 行，与 /tmp/rt.map 中的约 20706 行不同，因此我无法直接 grep classlist 文件。