一个 Java 小白维护一套没有文档的，代码凌乱的 Java 后台系统，遇到一些新手问题这里记录。

一、更新jar包

在更新 Java 后端程序时，需要修改一个 JAR 包里面的文件，替换里面的部分内容。

使用 jar -xvf xxx.jar 解压到当前文件夹，文件夹包含 META-INF/MANIFEST.MF 和其它要打包的文件。

替换要修改的文件后，使用 jar -cvfm xxx.jar META-INF/MANIFEST.MF xx 打包，其中 xx 表示其它要打包的文件。

MANIFEST.MF

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Manifest-Version: 1.0
Ant-Version: Apache Ant 1.6.1
Specification-Title: DCWLW
Class-Path: conn.jar commons-codec-1.3.jar commons-dbcp-1.2.2.jar comm
 ons-lang-2.4.jar commons-lang3-3.2.jar commons-logging-1.0.4.jar comm
 ons-pool-1.3.jar dom4j.jar httpclient-4.5.6.jar httpcore-4.4.11.jar j
 dom-1.0.jar jtds-1.2.jar log4j-1.2.14.jar ojdbc14.jar msutil.jar slf4
 j-api-1.6.6.jar slf4j-log4j12-1.6.6.jar sqljdbc4.jar
Created-By: xinli.zhangxlei
Specification-Version: 1.0
Main-Class: com.servs.main.ServiceInit

更新：在Linux下更简单的方法是，复制更改的文件，连同其路径，使用命令jar uf命令进行更新。

例如：

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jar uf WLWServ.jar com/servs/main/HandlerTest.class

二、查看数据库配置

在迁移服务后，需要修改数据库配置文件到当前使用的数据库，因此要改变其 IP 地址，为此找了好一会，最后仔细观察 log，才发现配置文件所在位置在 conn.jar 文件中，将其修改后重新打包。

db.properties

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#This is DataBase config files.
#Please copy to " tomcat\conf " file.properties

# postgresql
# user=xx
# password=yyyyy
# drivers=org.postgresql.Driver
# url=jdbc:postgresql://192.168.3.198:5432/radius

# sqlserver2000 -dts
#user=xx
#password=yyyyy
#drivers=net.sourceforge.jtds.jdbc.Driver
#url=jdbc:jtds:sqlserver://xx.xx.xxx.xx:1433/PHBase;SelectMethod=cursor

#sqlserver2005 -2.0  localhost
user=xx
password=yyyyy
drivers=com.microsoft.sqlserver.jdbc.SQLServerDriver
url=jdbc:sqlserver://xx.xx.xxx.xx;database=DCWLW;
 

#other
MaxConnectionCount=60
MaxIdleCount=3
MaxWait=1000

#MinConnectionCount=2
#ManageType=0

三、防火墙

早前在搬迁一些云服务器文件时，突然发现网站无法访问，最后查清是防火墙的问题，关闭防火墙后服务恢复正常。在搬迁服务器文件过程中，唯一有过的可疑操作是打开过网络共享，并共享了一个文件夹（该操作没有成功，可能阿里云服务器禁止网络共享），尚未清楚该操作是否与防火墙的策略有何关联。

四、tomcat添加SSL认证

之前的网站未经过 SSL 认证，没有 HTTPS 加密，微信小程序是不支持没有 HTTPS 加密的地址的，因此需要进行 SSL 认证。因为使用的阿里云服务器，阿里云有该服务。阿里云提供免费证书，申请配置完域名后，放到 tomcat 根目录 cert 文件夹下。

证书目录：

image-20211130095508197

修改 conf/server.xml 文件，配置 https 所用端口 443

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<?xml version='1.0' encoding='utf-8'?>

<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <Listener className="org.apache.catalina.core.JasperListener" />
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <GlobalNamingResources>
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>

  <Service name="Catalina">
    <Connector port="80" protocol="HTTP/1.1"
               maxHttpHeaderSize="8192"
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false"  acceptCount="100"
               connectionTimeout="20000" disableUploadTimeout="true" 
               redirectPort="8443"  URIEncoding="UTF-8"/>
    
    <Connector port="8443" protocol="org.apache.coyote.http11.Http11Protocol"
               maxThreads="150" SSLEnabled="true" scheme="https" secure="true"
               clientAuth="false" sslProtocol="TLS" />

    
	
	<Connector port="443"
    protocol="HTTP/1.1"
    SSLEnabled="true"
    scheme="https"
    secure="true"
    keystoreFile="D:\apache-tomcat-7.0.65\cert\5568913_liyunlong.xdt-iot.com.pfx"
    keystoreType="PKCS12"
    keystorePass="r0ftyhrF"
    clientAuth="false"
    SSLProtocol="TLSv1+TLSv1.1+TLSv1.2"
ciphers="TLS_RSA_WITH_AES_128_CBC_SHA,TLS_RSA_WITH_AES_256_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,TLS_RSA_WITH_AES_128_CBC_SHA256,TLS_RSA_WITH_AES_256_CBC_SHA256"/>

    <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

    <Engine name="Catalina" defaultHost="localhost">
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log." suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host>

	  <Host name="liyunlong.xdt-iot.com"  appBase="" unpackWARs="true" autoDeploy="true">
          <Context path="" docBase="D:\apache-tomcat-7.0.65\webapps_xassp\DCWLW" reloadable="true" > 
          </Context>
		  <Context path="/upload" docBase="D:\uploads"  reloadable="true"></Context>
		  <Context path="/download" docBase="D:\apache-tomcat-7.0.65\webapps_xassp\download"  reloadable="true"></Context>
          <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log." suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host> 

    </Engine>
  </Service>
</Server>

五、java程序未释放临时文件

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root@lyl-linux:WLWpack$ ps -ef | grep WLWServ
root     27719     1  5 14:10 ?        00:00:54 java -jar -Xms1536m -Xmx2046m -XX:PermSize=128M -XX:MaxPermSize=256M /opt/Xassp/DCServer/WLWServ.jar
root     30118 28413  0 14:26 pts/2    00:00:00 grep --color=auto WLWServ
root@lyl-linux:WLWpack$ ls -l /proc/27719/fd
total 0
lr-x------ 1 root root 64 May 11 14:10 0 -> /dev/null
l-wx------ 1 root root 64 May 11 14:10 1 -> /opt/Xassp/DCServer/DC.log
lr-x------ 1 root root 64 May 11 14:10 10 -> /dev/urandom
lr-x------ 1 root root 64 May 11 14:10 100 -> /usr/java/jdk1.8.0_151/jre/lib/jce.jar
lrwx------ 1 root root 64 May 11 14:10 101 -> socket:[65960083]
lrwx------ 1 root root 64 May 11 14:10 102 -> socket:[65958648]
lrwx------ 1 root root 64 May 11 14:10 103 -> socket:[65958649]
*
*
*
lrwx------ 1 root root 64 May 11 14:11 849 -> socket:[65962399]
lr-x------ 1 root root 64 May 11 14:10 85 -> /tmp/jar_cache1697996469127696081.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:11 850 -> socket:[65956493]
lrwx------ 1 root root 64 May 11 14:11 851 -> socket:[65956497]
lrwx------ 1 root root 64 May 11 14:11 852 -> socket:[65956667]
lrwx------ 1 root root 64 May 11 14:11 853 -> socket:[65962423]
lrwx------ 1 root root 64 May 11 14:11 855 -> socket:[65962615]
lr-x------ 1 root root 64 May 11 14:10 86 -> /tmp/jar_cache7396855417572440361.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:11 860 -> socket:[65967045]
lrwx------ 1 root root 64 May 11 14:11 861 -> socket:[65966819]
lr-x------ 1 root root 64 May 11 14:10 87 -> /tmp/jar_cache5532799349897305199.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:20 871 -> socket:[65968386]
lr-x------ 1 root root 64 May 11 14:10 88 -> /tmp/jar_cache3266479730475853680.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:20 880 -> socket:[65968209]
lrwx------ 1 root root 64 May 11 14:20 884 -> socket:[65967056]
lr-x------ 1 root root 64 May 11 14:10 89 -> /tmp/jar_cache8112640596215738372.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:20 894 -> socket:[65972740]
lrwx------ 1 root root 64 May 11 14:20 895 -> socket:[65972730]
lr-x------ 1 root root 64 May 11 14:10 9 -> /dev/random
lr-x------ 1 root root 64 May 11 14:10 90 -> /tmp/jar_cache5110604533158166258.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:20 900 -> socket:[65972734]
lr-x------ 1 root root 64 May 11 14:10 91 -> /tmp/jar_cache7000421609336413492.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:20 915 -> socket:[65969067]
lrwx------ 1 root root 64 May 11 14:20 917 -> socket:[65966968]
lr-x------ 1 root root 64 May 11 14:10 92 -> /tmp/jar_cache6363263715093382132.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:22 920 -> socket:[65972778]
lrwx------ 1 root root 64 May 11 14:22 922 -> socket:[65972339]
lrwx------ 1 root root 64 May 11 14:22 923 -> socket:[65968715]
lrwx------ 1 root root 64 May 11 14:22 924 -> socket:[65967706]
lr-x------ 1 root root 64 May 11 14:10 93 -> /tmp/jar_cache733013011657608974.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:24 931 -> socket:[65972801]
lrwx------ 1 root root 64 May 11 14:24 932 -> socket:[65972824]
lrwx------ 1 root root 64 May 11 14:24 933 -> socket:[65969142]
lrwx------ 1 root root 64 May 11 14:25 934 -> socket:[65972838]
lrwx------ 1 root root 64 May 11 14:25 935 -> socket:[65974276]
lrwx------ 1 root root 64 May 11 14:25 936 -> socket:[65974298]
lrwx------ 1 root root 64 May 11 14:25 937 -> socket:[65974306]
lrwx------ 1 root root 64 May 11 14:25 938 -> socket:[65972881]
lrwx------ 1 root root 64 May 11 14:25 939 -> socket:[65972882]
lr-x------ 1 root root 64 May 11 14:10 94 -> /tmp/jar_cache4426843942519086123.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:25 940 -> socket:[65972885]
lrwx------ 1 root root 64 May 11 14:25 941 -> socket:[65974317]
lrwx------ 1 root root 64 May 11 14:25 942 -> socket:[65972914]
lrwx------ 1 root root 64 May 11 14:25 943 -> socket:[65974398]
lrwx------ 1 root root 64 May 11 14:25 944 -> socket:[65972940]
lrwx------ 1 root root 64 May 11 14:25 945 -> socket:[65974409]
lrwx------ 1 root root 64 May 11 14:25 946 -> socket:[65972959]
lrwx------ 1 root root 64 May 11 14:25 947 -> socket:[65973448]
lrwx------ 1 root root 64 May 11 14:25 948 -> socket:[65974430]
lrwx------ 1 root root 64 May 11 14:25 949 -> socket:[65974440]
lr-x------ 1 root root 64 May 11 14:10 95 -> /tmp/jar_cache6962183311593254185.tmp (deleted)
lrwx------ 1 root root 64 May 11 14:25 950 -> socket:[65974476]
lrwx------ 1 root root 64 May 11 14:25 951 -> socket:[65974480]
lrwx------ 1 root root 64 May 11 14:25 952 -> socket:[65974506]
lrwx------ 1 root root 64 May 11 14:25 953 -> socket:[65974524]
lrwx------ 1 root root 64 May 11 14:25 954 -> socket:[65973053]
lrwx------ 1 root root 64 May 11 14:25 955 -> socket:[65974549]
lr-x------ 1 root root 64 May 11 14:10 96 -> /tmp/jar_cache3916538713653732339.tmp (deleted)
lr-x------ 1 root root 64 May 11 14:10 97 -> /usr/java/jdk1.8.0_151/jre/lib/resources.jar
l-wx------ 1 root root 64 May 11 14:10 98 -> /root/keep/DC_400.log
lrwx------ 1 root root 64 May 11 14:10 99 -> socket:[65958644]

以上，使用ps -ef | grep WLWServ查看WLWServ程序的进程号，然后用ls -l /proc/27719/fd查看进程占用的文件，发现很多线程使用deleted的文件。