jar解压后 如何把解压出来的文件夹 重新编译成jar ？？？

你不是只修改了一个配置文件吗？原来的那个jar文件还在吧，用winrar打开，但是别解压，直接替换你修改好的文件（找到winrar中那个文件，把你要换的文件用鼠标直接托进去替换掉）就行了，格式winrar会自动识别的，不用修改任何东西。

不用压缩，直接在jar包里面修改你需要修改的配置文件，改好了就能用了

如果修改某个文件，用7z取出来、处理完了，再放回去就好了

请参考

Usage: jar {ctxui}[vfm0Me] [jar-file] [manifest-file] [entry-point] [-C dir] files ...
Options:
-c create new archive
-t list table of contents for archive
-x extract named (or all) files from archive
-u update existing archive
-v generate verbose output on standard output
-f specify archive file name
-m include manifest information from specified manifest file
-e specify application entry point for stand-alone application
bundled into an executable jar file
-0 store only; use no ZIP compression
-M do not create a manifest file for the entries
-i generate index information for the specified jar files
-C change to the specified directory and include the following file
If any file is a directory then it is processed recursively.
The manifest file name, the archive file name and the entry point name are
specified in the same order as the 'm', 'f' and 'e' flags.

Example 1: to archive two class files into an archive called classes.jar:
jar cvf classes.jar Foo.class Bar.class
Example 2: use an existing manifest file 'mymanifest' and archive all the
files in the foo/ directory into 'classes.jar':
jar cvfm classes.jar mymanifest -C foo/ .

代码如下：
package ConnectionTest;
import java.sql.*;

public class testJDBC
{
public static void main(String[] args)
{

try

你配置改错了吧