java jar如果编写service接口 jar包如何提供接口服务

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laojean 2024-06-11 10:52:16

文章标签 服务器 jar java maven spring 文章分类 Java 后端开发

前言

在最近写项目的过程中，临近收尾，需要将java项目打成jar包放到服务器运行，对出现的一系列问题进行总结，方便日后查看

问题1：数据库远程连接不成功

现象

在cmd运行使用java -jar XXX.jar运行jar包时发现，出现以下错误，例如

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

等，经查询后发现是连接不上本地的数据库，可有以下解决措施

解决措施

第一步：检查端口是否开启
第二步：检查数据库是否支持远程连接，将localhost改为% 第三步：在本地navicat测试是否能连接
第四步：若以上三步都无法解决问题，还是建议将数据库直接放到服务器的数据库上，完美解决问题
第五步：数据库放到服务器数据库具体操作

如果有可视化面板，比较容易，正常操作即可
如果没有的话，进行下一步
转储sql文件，结构与数据
xhsell登录服务器
rz命令上传sql文件
上传成功后，使用mysql -u root -p，输入密码进入mysql
show databases；查看数据库
create database XXX；创建数据库
use XXX选择数据库
source /XXX.sql运行sql文件
出现如图所示，即为成功
show tables查看数据库的表的信息

问题二：使用bat运行jar包后，服务器也无法访问端口

现象

若服务器有可视化面板还行，如果没有，直接java -jar XXX.jar查看出现的错误，若出现如下错误

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:83)
	at org.mybatis.spring.transaction.SpringManagedTransaction.openConnection(SpringManagedTransaction.java:80)
	at org.mybatis.spring.transaction.SpringManagedTransaction.getConnection(SpringManagedTransaction.java:67)
	at org.apache.ibatis.executor.BaseExecutor.getConnection(BaseExecutor.java:337)
	at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:86)
	at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)
	at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:325)
	at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
	at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:89)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:151)
	... 63 common frames omitted
Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:828)
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:448)
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:241)
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:118)
	at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:232)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:112)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1645)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1709)
	at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:901)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1379)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1375)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:79)
	at org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource.getConnection(AbstractRoutingDataSource.java:194)
	at org.springframework.jdbc.datasource.DataSourceUtils.fetchConnection(DataSourceUtils.java:159)
	at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:117)
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
	... 73 common frames omitted
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
	at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
	at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89)
	at com.mysql.cj.NativeSession.connect(NativeSession.java:120)
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:948)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:818)
	... 89 common frames omitted
Caused by: java.net.UnknownHostException: localhsot: Name or service not known
	at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
	at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:929)
	at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1324)
	at java.net.InetAddress.getAllByName0(InetAddress.java:1277)
	at java.net.InetAddress.getAllByName(InetAddress.java:1193)
	at java.net.InetAddress.getAllByName(InetAddress.java:1127)
	at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:130)
	at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63)
	... 92 common frames omitted

说明不知道你在数据库配置时写的localhost是什么

解决措施

查询服务器数据库中可以使用的ip是什么

mysql -u root -p，输入密码，进入数据库
use mysql;
select user,host from user;

java jar如果编写service接口 jar包如何提供接口服务_spring

此时可以将localhost改为127.0.0.1

问题三：数据库连接仍然出现问题，连接失败，但报错原因与问题二不一致在问题而解决后，仍出现数据库如下报错

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
	at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
	at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89)
	at com.mysql.cj.NativeSession.connect(NativeSession.java:120)
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:948)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:818)
	... 89 common frames omitted
Caused by: java.net.NoRouteToHostException: No route to host (Host unreachable)
	at java.net.PlainSocketImpl.socketConnect(Native Method)
	at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:476)
	at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:218)
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:200)
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:394)
	at java.net.Socket.connect(Socket.java:606)
	at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:153)
	at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63)
	... 92 common frames omitted

查询后发现，服务器端口没开