java - 在 Java 中恢复使用 mysqldump 创建的备份文件时出错

Question

我有一个 Swing 应用程序，它允许用户备份或恢复数据库。对于备份，没问题。

对于导入，当在 mysql 命令行中完成时，一切正常，例如C:\Users\Admin71>mysql -u root -p philateliodb < C:\Export_DB_Philatelio_18_09_2014_12_39_34.sql

但是当尝试从 Java 代码中导入时，它不起作用。这是我使用的代码:

try
{
File file = fileChooser.getSelectedFile();

//DISABLE FOREIGN KEY CHECKS FOR IMPORT
Connection con = Share.connection;
Statement stmt = con.createStatement();
stmt.execute("SET FOREIGN_KEY_CHECKS=0");
stmt.close();
//////////
String dbUserName = "root";
String dbPassword = "";
String dbName = "philateliodb";
String executeCmd = "mysql -u " + dbUserName + " -p" + dbPassword + " " + dbName + " <" + "\""
                    + file.getCanonicalPath() + "\"";

Process runtimeProcess = Runtime.getRuntime().exec(executeCmd);
InputStream is = runtimeProcess.getInputStream();

int byteRead = -1;
while ( (byteRead = is.read()) != -1 )
{
    System.out.print((char) byteRead);
}

int processComplete = runtimeProcess.waitFor();

if ( processComplete == 0 )
{
    System.out.println("The database has been restored !");
}

else
{
    System.out.println("Error : the database could not be restored !");
}

//RE_ENABLE FOREIGN KEY CHECKS AFTER IMPORT
stmt = con.createStatement();
stmt.execute("SET FOREIGN_KEY_CHECKS=1");
stmt.close();
//////////
}
catch (IOException e)
{
e.printStackTrace();
}
catch (SQLException e)
{
e.printStackTrace();
}
catch (InterruptedException e)
{
e.printStackTrace();
}

但我总是得到“错误:无法恢复数据库!”消息。

这也是我从 Eclipse 的控制台输出中得到的:

   mysql  Ver 14.14 Distrib 5.6.17, for Win64 (x86_64)
   Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Usage: mysql [OPTIONS] [database]
  -?, --help          Display this help and exit.
  -I, --help          Synonym for -?
  --auto-rehash       Enable automatic rehashing. One doesn't need to use
                      'rehash' to get table and field completion, but startup
                      and reconnecting may take a longer time. Disable with
                      --disable-auto-rehash.
                      (Defaults to on; use --skip-auto-rehash to disable.)
  -A, --no-auto-rehash 
                      No automatic rehashing. One has to use 'rehash' to get
                      table and field completion. This gives a quicker start of
                      mysql and disables rehashing on reconnect.
  --auto-vertical-output 
                      Automatically switch to vertical output mode if the
                      result is wider than the terminal width.
  -B, --batch         Don't use history file. Disable interactive behavior.
                      (Enables --silent.)
  --bind-address=name IP address to bind to.
  --character-sets-dir=name 
                      Directory for character set files.
  --column-type-info  Display column type information.
  -c, --comments      Preserve comments. Send comments to the server. The
                      default is --skip-comments (discard comments), enable
                      with --comments.
  -C, --compress      Use compression in server/client protocol.
  -#, --debug[=#]     This is a non-debug version. Catch this and exit.
  --debug-check       Check memory and open file usage at exit.
  -T, --debug-info    Print some debug info at exit.
  -D, --database=name Database to use.
  --default-character-set=name 
                      Set the default character set.
  --delimiter=name    Delimiter to be used.
  --enable-cleartext-plugin 
                      Enable/disable the clear text authentication plugin.
  -e, --execute=name  Execute command and quit. (Disables --force and history
                      file.)
  -E, --vertical      Print the output of a query (rows) vertically.
  -f, --force         Continue even if we get an SQL error.
  -G, --named-commands 
                      Enable named commands. Named commands mean this program's
                      internal commands; see mysql> help . When enabled, the
                      named commands can be used from any line of the query,
                      otherwise only from the first line, before an enter.
                      Disable with --disable-named-commands. This option is
                      disabled by default.
  -i, --ignore-spaces Ignore space after function names.
  --init-command=name SQL Command to execute when connecting to MySQL server.
                      Will automatically be re-executed when reconnecting.
  --local-infile      Enable/disable LOAD DATA LOCAL INFILE.
  -b, --no-beep       Turn off beep on error.
  -h, --host=name     Connect to host.
  -H, --html          Produce HTML output.
  -X, --xml           Produce XML output.
  --line-numbers      Write line numbers for errors.
                      (Defaults to on; use --skip-line-numbers to disable.)
  -L, --skip-line-numbers 
                      Don't write line number for errors.
  -n, --unbuffered    Flush buffer after each query.
  --column-names      Write column names in results.
                      (Defaults to on; use --skip-column-names to disable.)
  -N, --skip-column-names 
                      Don't write column names in results.
  --sigint-ignore     Ignore SIGINT (CTRL-C).
  -o, --one-database  Ignore statements except those that occur while the
                      default database is the one named at the command line.
  -p, --password[=name] 
                      Password to use when connecting to server. If password is
                      not given it's asked from the tty.
  -W, --pipe          Use named pipes to connect to server.
  -P, --port=#        Port number to use for connection or 0 for default to, in
                      order of preference, my.cnf, $MYSQL_TCP_PORT,
                      /etc/services, built-in default (3306).
  --prompt=name       Set the mysql prompt to this value.
  --protocol=name     The protocol to use for connection (tcp, socket, pipe,
                      memory).
  -q, --quick         Don't cache result, print it row by row. This may slow
                      down the server if the output is suspended. Doesn't use
                      history file.
  -r, --raw           Write fields without conversion. Used with --batch.
  --reconnect         Reconnect if the connection is lost. Disable with
                      --disable-reconnect. This option is enabled by default.
                      (Defaults to on; use --skip-reconnect to disable.)
  -s, --silent        Be more silent. Print results with a tab as separator,
                      each row on new line.
  --shared-memory-base-name=name 
                      Base name of shared memory.
  -S, --socket=name   The socket file to use for connection.
  --ssl               Enable SSL for connection (automatically enabled with
                      other flags).
  --ssl-ca=name       CA file in PEM format (check OpenSSL docs, implies
                      --ssl).
  --ssl-capath=name   CA directory (check OpenSSL docs, implies --ssl).
  --ssl-cert=name     X509 cert in PEM format (implies --ssl).
  --ssl-cipher=name   SSL cipher to use (implies --ssl).
  --ssl-key=name      X509 key in PEM format (implies --ssl).
  --ssl-crl=name      Certificate revocation list (implies --ssl).
  --ssl-crlpath=name  Certificate revocation list path (implies --ssl).
  --ssl-verify-server-cert 
                      Verify server's "Common Name" in its cert against
                      hostname used when connecting. This option is disabled by
                      default.
  -t, --table         Output in table format.
  --tee=name          Append everything into outfile. See interactive help (\h)
                      also. Does not work in batch mode. Disable with
                      --disable-tee. This option is disabled by default.
  -u, --user=name     User for login if not current user.
  -U, --safe-updates  Only allow UPDATE and DELETE that uses keys.
  -U, --i-am-a-dummy  Synonym for option --safe-updates, -U.
  -v, --verbose       Write more. (-v -v -v gives the table output format).
  -V, --version       Output version information and exit.
  -w, --wait          Wait and retry if connection is down.
  --connect-timeout=# Number of seconds before connection timeout.
  --max-allowed-packet=# 
                      The maximum packet length to send to or receive from
                      server.
  --net-buffer-length=# 
                      The buffer size for TCP/IP and socket communication.
  --select-limit=#    Automatic limit for SELECT when using --safe-updates.
  --max-join-size=#   Automatic limit for rows in a join when using
                      --safe-updates.
  --secure-auth       Refuse client connecting to server if it uses old
                      (pre-4.1.1) protocol.
                      (Defaults to on; use --skip-secure-auth to disable.)
  --server-arg=name   Send embedded server this as a parameter.
  --show-warnings     Show warnings after every statement.
  --plugin-dir=name   Directory for client-side plugins.
  --default-auth=name Default authentication client-side plugin to use.
  --histignore=name   A colon-separated list of patterns to keep statements
                      from getting logged into mysql history.
  --binary-mode       By default, ASCII '\0' is disallowed and '\r\n' is
                      translated to '\n'. This switch turns off both features,
                      and also turns off parsing of all clientcommands except
                      \C and DELIMITER, in non-interactive mode (for input
                      piped to mysql or loaded using the 'source' command).
                      This is necessary when processing output from mysqlbinlog
                      that may contain blobs.
  --connect-expired-password 
                      Notify the server that this client is prepared to handle
                      expired password sandbox mode.

Default options are read from the following files in the given order:
C:\Windows\my.ini C:\Windows\my.cnf C:\my.ini C:\my.cnf C:\wamp\bin\mysql\mysql5.6.17\my.ini   C:\wamp\bin\mysql\mysql5.6.17\my.cnf 
The following groups are read: mysql client
The following options may be given as the first argument:
--print-defaults        Print the program argument list and exit.
--no-defaults           Don't read default options from any option file,
                        except for login file.
--defaults-file=#       Only read default options from the given file #.
--defaults-extra-file=# Read this file after the global files are read.
--defaults-group-suffix=#
                        Also read groups with concat(group, suffix)
--login-path=#          Read this path from the login file.

Variables (--variable-name=value)
and boolean options {FALSE|TRUE}  Value (after reading options)
--------------------------------- ----------------------------------------
auto-rehash                       FALSE
auto-vertical-output              FALSE
bind-address                      (No default value)
character-sets-dir                (No default value)
column-type-info                  FALSE
comments                          FALSE
compress                          FALSE
debug-check                       FALSE
debug-info                        FALSE
database                          (No default value)
default-character-set             auto
delimiter                         ;
enable-cleartext-plugin           FALSE
vertical                          FALSE
force                             FALSE
named-commands                    FALSE
ignore-spaces                     FALSE
init-command                      (No default value)
local-infile                      FALSE
no-beep                           FALSE
host                              (No default value)
html                              FALSE
xml                               FALSE
line-numbers                      TRUE
unbuffered                        FALSE
column-names                      TRUE
sigint-ignore                     FALSE
port                              3306
prompt                            mysql> 
quick                             FALSE
raw                               FALSE
reconnect                         FALSE
shared-memory-base-name           (No default value)
socket                            /tmp/mysql.sock
ssl                               FALSE
ssl-ca                            (No default value)
ssl-capath                        (No default value)
ssl-cert                          (No default value)
ssl-cipher                        (No default value)
ssl-key                           (No default value)
ssl-crl                           (No default value)
ssl-crlpath                       (No default value)
ssl-verify-server-cert            FALSE
table                             FALSE
user                              root
safe-updates                      FALSE
i-am-a-dummy                      FALSE
connect-timeout                   0
max-allowed-packet                16777216
net-buffer-length                 16384
select-limit                      1000
max-join-size                     1000000
secure-auth                       TRUE
show-warnings                     FALSE
plugin-dir                        (No default value)
default-auth                      (No default value)
histignore                        (No default value)
binary-mode                       FALSE
connect-expired-password          FALSE

这个 mysql 输出似乎没有明确指出错误。或者是吗？有人有想法吗？

Answer 1

您发布的 MySQL 输出是帮助/用法 信息，通常在您要求或错误调用 mysql 时看到。您的第一个问题是您尝试重定向并使用单参数 Runtime.getRuntime().exec(String) .

是windows cmd.exe或解释 < 的 unix/linux shell表示重定向 stdin从某个地方，然后打开并启动程序，其中的文件描述符设置为进行重定向。

Runtime.exec 不是命令行处理器，<你在你的 executeCommand 中使用对它毫无意义。它只是作为另一个参数传递给程序 mysql ，它不知道如何处理它。

因此，您对 System.out.print((char) byteRead); 的使用只是打印到 Java 程序的标准输出，而不是重定向到 mysql 的标准输入。您将不得不使用 runtimeProcess.getOutputStream()其中，从 javadoc 中，“返回连接到子进程的正常输入的输出流”，然后将您的文件内容提供给 that 流，而不是 System.out .

作为最佳实践，永远不要使用 .exec(String command) -- 始终使用 .exec(String[] cmdarray)再次是因为 .exec 不是命令处理器，它只是在空格上打断单个字符串(打断所有使用带空格的文件名的尝试。
使用 String[]表单使您可以完全控制将哪些实际参数传递给您调用的程序。
另请参阅 .exec(cmdarry, envp, File dir)以便更好地控制流程。