java - 从服务器收到未知的初始字符集索引“255”，但我不使用 pom.xml
问题描述
我已经看过这个话题：Unknown initial character set index '255' received from server
但我没有 pom.xml，我使用 .jar 作为依赖项。我已经在我的项目中设置了最近和/或当前的 MySQL 连接器，但异常仍然存在。
我正在使用 MySQL 8.0
这在我将 MySQL 5 更新到 8 后开始发生
这是我的连接类：
package br.com.sat.util;
import java.sql.Connection;
import java.sql.*;
public class ConnectionFactory {
public static Connection getConnection() throws Exception {
try {
Class.forName("com.mysql.jdbc.Driver");
return DriverManager.getConnection("jdbc:mysql://localhost:3306/test_wim",
"root", "*******");
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
public static void closeConnection(Connection conn, PreparedStatement ps, ResultSet rs) throws Exception {
close(conn, ps, rs);
}
public static void closeConnection(Connection conn, PreparedStatement ps) throws Exception {
close(conn, ps, null);
}
private static void close(Connection conn, PreparedStatement ps, ResultSet rs) throws Exception {
try {
if (rs != null)
rs.close();
if (ps != null)
ps.close();
if (conn != null)
conn.close();
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
}
和错误：
java.lang.Exception: erro:
Unknown initial character set index '255' received from server. Initial client character set can be forced via the 'characterEncoding' property.
at br.com.poc.dao.RealtimeDAO.<init>(RealtimeDAO.java:31)
at br.com.poc.controller.RealtimeMB.verNovoInsert(RealtimeMB.java:286)
at br.com.poc.controller.RealtimeMB.<init>(RealtimeMB.java:82)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:186)
at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:100)
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:257)
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:117)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:94)
at org.apache.el.parser.AstValue.getValue(AstValue.java:137)
at org.apache.el.parser.AstEqual.getValue(AstEqual.java:37)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:190)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at com.sun.faces.facelets.tag.TagAttributeImpl.getObject(TagAttributeImpl.java:356)
at com.sun.faces.facelets.tag.TagAttributeImpl.getBoolean(TagAttributeImpl.java:150)
at com.sun.faces.facelets.tag.jstl.core.ChooseWhenHandler.isTestTrue(ChooseWhenHandler.java:87)
at com.sun.faces.facelets.tag.jstl.core.ChooseHandler.apply(ChooseHandler.java:104)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
at com.sun.faces.facelets.tag.ui.DefineHandler.applyDefinition(DefineHandler.java:106)
at com.sun.faces.facelets.tag.ui.CompositionHandler.apply(CompositionHandler.java:201)
at com.sun.faces.facelets.impl.DefaultFaceletContext$TemplateManager.apply(DefaultFaceletContext.java:395)
at com.sun.faces.facelets.impl.DefaultFaceletContext.includeDefinition(DefaultFaceletContext.java:366)
at com.sun.faces.facelets.tag.ui.InsertHandler.apply(InsertHandler.java:111)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
at javax.faces.view.facelets.DelegatingMetaTagHandler.applyNextHandler(DelegatingMetaTagHandler.java:137)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:203)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:120)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:95)
at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:93)
at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:87)
at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:312)
at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:371)
at com.sun.faces.facelets.impl.DefaultFacelet.include(DefaultFacelet.java:350)
at com.sun.faces.facelets.impl.DefaultFaceletContext.includeFacelet(DefaultFaceletContext.java:199)
at com.sun.faces.facelets.tag.ui.CompositionHandler.apply(CompositionHandler.java:169)
at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:93)
at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:87)
at com.sun.faces.facelets.impl.DefaultFacelet.apply(DefaultFacelet.java:161)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.buildView(FaceletViewHandlingStrategy.java:995)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:99)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
RealtimeDAO 中的此错误发生在构造函数中：
private Connection conn;
protected ConnectionFactory connection = new ConnectionFactory();
public RealtimeDAO() throws Exception {
try {
this.conn = ConnectionFactory.getConnection();
} catch (Exception e) {
throw new Exception("erro: \n" + e.getMessage());
}
}
解决方案
该错误与 MySQL 8.0 中默认字符编码的更改有关，因此使用不理解新编码的旧连接器将失败。如果您已更新到最新的 MySQL Connector/J（8.0 版），您还必须进行一些更改。其中之一是类名已更改为 com.mysql.cj.jdbc.Driver，否则您可能仍使用旧驱动程序。
另请参阅 Connector/J 的 MySQL 升级文档： https ://dev.mysql.com/doc/connector-j/8.0/en/connector-j-upgrading-to-8.0.html
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