jdbc连接数据库,可以加载驱动,数据库内却取不到值(NullPointException)?

我用两种途径连接数据库,一种是:

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这一种应该没问题



但是在另一种途径遇到了以下问题:

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//以下是异常信息:
第一次提问,请问还需要什么信息orz



换了个电脑 代码进行修改之后 项目能够正常运行了
在原来的电脑上仍有以下报错:

数据库驱动加载成功!
Exceptionconn
java.lang.NullPointerException
findall failed
    at javax.xml.bind.DatatypeConverter.parseHexBinary(DatatypeConverter.java:310)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.sendLogon(SQLServerConnection.java:4061)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.logon(SQLServerConnection.java:3157)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.access$100(SQLServerConnection.java:82)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection$LogonCommand.doExecute(SQLServerConnection.java:3121)
    at com.microsoft.sqlserver.jdbc.TDSCommand.execute(IOBuffer.java:7151)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(SQLServerConnection.java:2478)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectHelper(SQLServerConnection.java:2026)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:1687)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectInternal(SQLServerConnection.java:1528)
    at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(SQLServerConnection.java:866)
    at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:569)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
    at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
    at ch04.utils.BookUtils.getConnection(BookUtils.java:20)
    at ch04.dao.impl.BookDaoImpl.findByAll(BookDaoImpl.java:88)
    at ch04.service.impl.BookservicesImpl.findByAll(BookservicesImpl.java:38)
    at ch04.controller.BookAction.showall(BookAction.java:127)
    at ch04.controller.BookAction.doPost(BookAction.java:46)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    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:53)
    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:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:835)
java.lang.NullPointerException
    at ch04.dao.impl.BookDaoImpl.findByAll(BookDaoImpl.java:92)
    at ch04.service.impl.BookservicesImpl.findByAll(BookservicesImpl.java:38)
    at ch04.controller.BookAction.showall(BookAction.java:127)
    at ch04.controller.BookAction.doPost(BookAction.java:46)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    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:53)
    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:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:835)
[]

weixin_44285933
Asterisk* 以下是异常信息: `java 数据库驱动加载成功! Exceptionconn java.lang.NullPointerException at javax.xml.bind.DatatypeConverter.parseHexBinary(DatatypeConverter.java:310) at com.microsoft.sqlserver.jdbc.SQLServerConnection.sendLogon(SQLServerConnection.java:4061) at com.microsoft.sqlserver.jdbc.SQLServerConnection.logon(SQLServerConnection.java:3157) at com.microsoft.sqlserver.jdbc.SQLServerConnection.access$100(SQLServerConnection.java:82) at com.microsoft.sqlserver.jdbc.SQLServerConnection$LogonCommand.doExecute(SQLServerConnection.java:3121) at com.microsoft.sqlserver.jdbc.TDSCommand.execute(IOBuffer.java:7151) at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(SQLServerConnection.java:2478) at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectHelper(SQLServerConnection.java:2026) at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:1687) at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectInternal(SQLServerConnection.java:1528) at com.microsoft.sqlserver
8 个月之前 回复

1个回答

看代码不是 getConnection 方法的问题,JDBC 连接没错。
看看 at ch04.dao.impl.BookDaoImpl.findByAll(BookDaoImpl.java:92) 这个类的 92 行是怎么写的,查询的是什么表,表中有没有特殊类型的字段。
第一个图中正确的是因为执行了一个简单的查询语句,而报错的那种写法可能是隐藏在 DAO 的查询过程有问题,再排查一下。

weixin_44285933
Asterisk* 感谢您呀 换了个电脑 代码进行修改之后 项目能够正常运行了 如果方便的话 想问下您能根据上面的异常看出这是eclipse还是sqlserver的问题么T_T
8 个月之前 回复
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