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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

转载 作者：行者123 更新时间：2023-11-29 16:13:17 25 4
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我已经看过这个主题: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。

我使用的是MySQL 8.0

在我将 MySQL 5 更新到 8 后，这种情况开始发生

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());
        }
    }

最佳答案

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会失败。如果您已更新到最新的 MySQL Connector/J(版本 8.0)，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，否则您可能仍然使用旧的驱动程序。

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

关于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，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55063188/

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