有效沟通问答-【官方】百战程序员_IT在线教育培训机构

package com.xh.StringBuilderAndBuffer;

public class text2 {
    public static void main(String[] args) {
        String s = "";
        StringBuilder sb = new StringBuilder("");
        long num1 = Runtime.getRuntime().freeMemory();//获取系统剩余内存空间
        long time1 = System.currentTimeMillis();//获取现在的时间；
        for(int i = 0;i < 5000;i++){
            s = s + i;
        }
        long num2 = Runtime.getRuntime().freeMemory();//获取系统剩余内存空间
        long time2 = System.currentTimeMillis();//获取现在的时间；
        System.out.println(num2-num1);
        System.out.println(time2 - time1);

        num1 = Runtime.getRuntime().freeMemory();//获取系统剩余内存空间
        time1 = System.currentTimeMillis();//获取现在的时间；
        for(int i = 0;i < 5000;i++){
            sb.append(i);
        }
        num2 = Runtime.getRuntime().freeMemory();//获取系统剩余内存空间
        time2 = System.currentTimeMillis();//获取现在的时间；
        System.out.println(num2-num1);
        System.out.println(time2 - time1);
    }
}

JAVA 全系列/第二阶段：JAVA 基础深化和提高/常用类 34053楼

老师您好，请问一下在用model传入的数据，用thymeleaf写出来会报红线，但是不影响显示和运行。

上一节中我是用注释来解决的，但是这一节中的date又会报红，

这是什么原因造成的呢，有没有一次性让它不报红的方法呢？

<!--@thymesVar id="msg" type="String"-->

JAVA 全系列/第八阶段：SpringBoot与MybatisPlus/Spring Boot（旧） 34054楼

老师，请问，使用root用户修改普通用户的密码，这个代码为什么在dos窗口中写了是这种呢，在navicat中写代码就可以修改成功

Python 全系列/第五阶段：数据库编程/mysql的使用 34055楼

老师请问这为什么要用return 它输入的不是一个字符串吗咋不用print

Python 全系列/第一阶段：Python入门/面向对象 34056楼

老师我的项目出现了一个很奇怪的bug，当我跟老师一样添加c.tld文件之后再添加 taglib 指令标签

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>代码里面的forEach关键字出现异常的红色，此时启动Tomcat报错

报错信息如下：

D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34\bin\catalina.bat run

[2020-10-15 09:50:43,165] Artifact mybatiswebdemoTest:war exploded: Waiting for server connection to start artifact deployment...

Using CATALINA_BASE: "C:\Users\admin\AppData\Local\JetBrains\IntelliJIdea2020.1\tomcat\Tomcat_9_0_34_mybatiswebdemoTest"

Using CATALINA_HOME: "D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34"

Using CATALINA_TMPDIR: "D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34\temp"

Using JRE_HOME: "D:\Java\jdk-14.0.2_windows-x64_bin\jdk-14.0.2"

Using CLASSPATH: "D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34\bin\bootstrap.jar;D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34\bin\tomcat-juli.jar"

NOTE: Picked up JDK_JAVA_OPTIONS: --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED

15-Oct-2020 21:50:44.590 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server.服务器版本: Apache Tomcat/9.0.34

15-Oct-2020 21:50:44.592 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 服务器构建: Apr 3 2020 12:02:52 UTC

15-Oct-2020 21:50:44.593 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 服务器版本号(：9.0.34.0

15-Oct-2020 21:50:44.594 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS Name: Windows 10

15-Oct-2020 21:50:44.594 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS.版本: 10.0

15-Oct-2020 21:50:44.594 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 架构: amd64

15-Oct-2020 21:50:44.594 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Java 环境变量: D:\Java\jdk-14.0.2_windows-x64_bin\jdk-14.0.2

15-Oct-2020 21:50:44.594 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM 版本: 14.0.2+12-46

15-Oct-2020 21:50:44.594 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM.供应商: Oracle Corporation

15-Oct-2020 21:50:44.595 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_BASE：[C:\Users\admin\AppData\Local\JetBrains\IntelliJIdea2020.1\tomcat\Tomcat_9_0_34_mybatiswebdemoTest]

15-Oct-2020 21:50:44.596 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_HOME: D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34

15-Oct-2020 21:50:44.597 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[--add-opens=java.base/java.lang=ALL-UNNAMED]

15-Oct-2020 21:50:44.597 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[--add-opens=java.base/java.io=ALL-UNNAMED]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[--add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Djava.util.logging.config.file=C:\Users\admin\AppData\Local\JetBrains\IntelliJIdea2020.1\tomcat\Tomcat_9_0_34_mybatiswebdemoTest\conf\logging.properties]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dcom.sun.management.jmxremote=]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dcom.sun.management.jmxremote.port=1099]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dcom.sun.management.jmxremote.ssl=false]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dcom.sun.management.jmxremote.password.file=C:\Users\admin\AppData\Local\JetBrains\IntelliJIdea2020.1\tomcat\Tomcat_9_0_34_mybatiswebdemoTest\jmxremote.password]

15-Oct-2020 21:50:44.598 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dcom.sun.management.jmxremote.access.file=C:\Users\admin\AppData\Local\JetBrains\IntelliJIdea2020.1\tomcat\Tomcat_9_0_34_mybatiswebdemoTest\jmxremote.access]

15-Oct-2020 21:50:44.599 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Djava.rmi.server.hostname=127.0.0.1]

15-Oct-2020 21:50:44.599 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Djdk.tls.ephemeralDHKeySize=2048]

15-Oct-2020 21:50:44.599 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Djava.protocol.handler.pkgs=org.apache.catalina.webresources]

15-Oct-2020 21:50:44.599 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dignore.endorsed.dirs=]

15-Oct-2020 21:50:44.599 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dcatalina.base=C:\Users\admin\AppData\Local\JetBrains\IntelliJIdea2020.1\tomcat\Tomcat_9_0_34_mybatiswebdemoTest]

15-Oct-2020 21:50:44.599 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Dcatalina.home=D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34]

15-Oct-2020 21:50:44.600 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log 命令行参数：[-Djava.io.tmpdir=D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34\temp]

15-Oct-2020 21:50:44.600 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent Loaded APR based Apache Tomcat Native library [1.2.23] using APR version [1.7.0].

15-Oct-2020 21:50:44.600 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].

15-Oct-2020 21:50:44.601 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent APR/OpenSSL配置：useAprConnector[false]，useOpenSSL[true]

15-Oct-2020 21:50:44.610 信息 [main] org.apache.catalina.core.AprLifecycleListener.initializeSSL OpenSSL successfully initialized [OpenSSL 1.1.1c 28 May 2019]

15-Oct-2020 21:50:44.878 信息 [main] org.apache.coyote.AbstractProtocol.init 初始化协议处理器 ["http-nio-8080"]

15-Oct-2020 21:50:44.970 信息 [main] org.apache.catalina.startup.Catalina.load 服务器在[726]毫秒内初始化

15-Oct-2020 21:50:45.031 信息 [main] org.apache.catalina.core.StandardService.startInternal Starting service [Catalina]

15-Oct-2020 21:50:45.031 信息 [main] org.apache.catalina.core.StandardEngine.startInternal 正在启动 Servlet 引擎：[Apache Tomcat/9.0.34]

15-Oct-2020 21:50:45.470 信息 [main] org.apache.coyote.AbstractProtocol.start 开始协议处理句柄["http-nio-8080"]

15-Oct-2020 21:50:45.489 信息 [main] org.apache.catalina.startup.Catalina.start Server startup in [519] milliseconds

Connected to server

[2020-10-15 09:50:45,967] Artifact mybatiswebdemoTest:war exploded: Artifact is being deployed, please wait...

15-Oct-2020 21:50:47.175 信息 [RMI TCP Connection(5)-127.0.0.1] org.apache.jasper.servlet.TldScanner.scanJars 至少有一个JAR被扫描用于TLD但尚未包含TLD。为此记录器启用调试日志记录，以获取已扫描但未在其中找到TLD的完整JAR列表。在扫描期间跳过不需要的JAR可以缩短启动时间和JSP编译时间。

[2020-10-15 09:50:47,196] Artifact mybatiswebdemoTest:war exploded: Artifact is deployed successfully

[2020-10-15 09:50:47,196] Artifact mybatiswebdemoTest:war exploded: Deploy took 1,229 milliseconds

<2020-10-15 21:50:48,065> DEBUG (LogFactory.java:105) [http-nio-8080-exec-1] (org.apache.ibatis.logging.LogFactory) - Logging initialized using 'class org.apache.ibatis.logging.slf4j.Slf4jImpl' adapter.

<2020-10-15 21:50:48,081> DEBUG (VFS.java:116) [http-nio-8080-exec-1] (org.apache.ibatis.io.VFS) - Class not found: org.jboss.vfs.VFS

<2020-10-15 21:50:48,081> DEBUG (JBoss6VFS.java:149) [http-nio-8080-exec-1] (org.apache.ibatis.io.JBoss6VFS) - JBoss 6 VFS API is not available in this environment.

<2020-10-15 21:50:48,085> DEBUG (VFS.java:116) [http-nio-8080-exec-1] (org.apache.ibatis.io.VFS) - Class not found: org.jboss.vfs.VirtualFile

<2020-10-15 21:50:48,087> DEBUG (VFS.java:64) [http-nio-8080-exec-1] (org.apache.ibatis.io.VFS) - VFS implementation org.apache.ibatis.io.JBoss6VFS is not valid in this environment.

<2020-10-15 21:50:48,087> DEBUG (VFS.java:74) [http-nio-8080-exec-1] (org.apache.ibatis.io.VFS) - Using VFS adapter org.apache.ibatis.io.DefaultVFS

<2020-10-15 21:50:48,090> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/

<2020-10-15 21:50:48,091> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/

<2020-10-15 21:50:48,128> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: Users.class

<2020-10-15 21:50:48,131> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: UsersExample.class

<2020-10-15 21:50:48,135> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: UsersExample$Criteria.class

<2020-10-15 21:50:48,139> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: UsersExample$Criterion.class

<2020-10-15 21:50:48,142> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: UsersExample$GeneratedCriteria.class

<2020-10-15 21:50:48,145> DEBUG (DefaultVFS.java:111) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Listing file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/

<2020-10-15 21:50:48,145> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/Users.class

<2020-10-15 21:50:48,146> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/Users.class

<2020-10-15 21:50:48,148> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: 漱壕 : ?

<2020-10-15 21:50:48,150> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample.class

<2020-10-15 21:50:48,150> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample.class

<2020-10-15 21:50:48,151> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: 漱壕 : O

<2020-10-15 21:50:48,153> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample$Criteria.class

<2020-10-15 21:50:48,153> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample$Criteria.class

<2020-10-15 21:50:48,154> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: 漱壕 : ?

<2020-10-15 21:50:48,157> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample$Criterion.class

<2020-10-15 21:50:48,158> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample$Criterion.class

<2020-10-15 21:50:48,159> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: 漱壕 : I %com/bjsxt/pojo/UsersExample$Criterion condition Ljava/lang/String;

<2020-10-15 21:50:48,160> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample$GeneratedCriteria.class

<2020-10-15 21:50:48,161> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/pojo/UsersExample$GeneratedCriteria.class

<2020-10-15 21:50:48,162> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: 漱壕 : ?

<2020-10-15 21:50:48,163> DEBUG (ResolverUtil.java:288) [http-nio-8080-exec-1] (org.apache.ibatis.io.ResolverUtil) - Checking to see if class com.bjsxt.pojo.Users matches criteria [is assignable to Object]

<2020-10-15 21:50:48,169> DEBUG (ResolverUtil.java:288) [http-nio-8080-exec-1] (org.apache.ibatis.io.ResolverUtil) - Checking to see if class com.bjsxt.pojo.UsersExample$Criteria matches criteria [is assignable to Object]

<2020-10-15 21:50:48,177> DEBUG (ResolverUtil.java:288) [http-nio-8080-exec-1] (org.apache.ibatis.io.ResolverUtil) - Checking to see if class com.bjsxt.pojo.UsersExample$Criterion matches criteria [is assignable to Object]

<2020-10-15 21:50:48,181> DEBUG (ResolverUtil.java:288) [http-nio-8080-exec-1] (org.apache.ibatis.io.ResolverUtil) - Checking to see if class com.bjsxt.pojo.UsersExample$GeneratedCriteria matches criteria [is assignable to Object]

<2020-10-15 21:50:48,305> DEBUG (PooledDataSource.java:363) [http-nio-8080-exec-1] (org.apache.ibatis.datasource.pooled.PooledDataSource) - PooledDataSource forcefully closed/removed all connections.

<2020-10-15 21:50:48,315> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/mapper/

<2020-10-15 21:50:48,315> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/mapper/

<2020-10-15 21:50:48,317> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: UsersMapper.class

<2020-10-15 21:50:48,321> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: UsersMapper.xml

<2020-10-15 21:50:48,324> DEBUG (DefaultVFS.java:111) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Listing file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/mapper/

<2020-10-15 21:50:48,324> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/mapper/UsersMapper.class

<2020-10-15 21:50:48,325> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/mapper/UsersMapper.class

<2020-10-15 21:50:48,326> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: 漱壕 : com/bjsxt/mapper/UsersMapper java/lang/Object countByExample (Lcom/bjsxt/pojo/UsersExample;)I deleteByExample deleteByPrimaryKey (Ljava/lang/Integer;)I insert (Lcom/bjsxt/pojo/Users;)I insertSelective selectByExample /(Lcom/bjsxt/pojo/UsersExample;)Ljava/util/List; Signature G(Lcom/bjsxt/pojo/UsersExample;)Ljava/util/List<Lcom/bjsxt/pojo/Users;>; selectByPrimaryKey +(Ljava/lang/Integer;)Lcom/bjsxt/pojo/Users; updateByExampleSelective 6(Lcom/bjsxt/pojo/Users;Lcom/bjsxt/pojo/UsersExample;)I "RuntimeVisibleParameterAnnotations %Lorg/apache/ibatis/annotations/Param; value record example updateByExample updateByPrimaryKeySelective updateByPrimaryKey

<2020-10-15 21:50:48,328> DEBUG (DefaultVFS.java:220) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Find JAR URL: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/mapper/UsersMapper.xml

<2020-10-15 21:50:48,328> DEBUG (DefaultVFS.java:247) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Not a JAR: file:/D:/J2EE项目/MybatisProject/mybatiswebdemoTest/out/artifacts/mybatiswebdemoTest_war_exploded/WEB-INF/classes/com/bjsxt/mapper/UsersMapper.xml

<2020-10-15 21:50:48,329> DEBUG (DefaultVFS.java:100) [http-nio-8080-exec-1] (org.apache.ibatis.io.DefaultVFS) - Reader entry: <?xml version="1.0" encoding="UTF-8" ?>

<2020-10-15 21:50:48,330> DEBUG (ResolverUtil.java:288) [http-nio-8080-exec-1] (org.apache.ibatis.io.ResolverUtil) - Checking to see if class com.bjsxt.mapper.UsersMapper matches criteria [is assignable to Object]

<2020-10-15 21:50:54,031> DEBUG (LoggingCache.java:60) [http-nio-8080-exec-5] (SQL_CACHE) - Cache Hit Ratio [SQL_CACHE]: 0.0

<2020-10-15 21:50:54,138> DEBUG (JdbcTransaction.java:137) [http-nio-8080-exec-5] (org.apache.ibatis.transaction.jdbc.JdbcTransaction) - Opening JDBC Connection

Thu Oct 15 21:50:54 CST 2020 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

<2020-10-15 21:50:54,582> DEBUG (PooledDataSource.java:434) [http-nio-8080-exec-5] (org.apache.ibatis.datasource.pooled.PooledDataSource) - Created connection 1614127273.

<2020-10-15 21:50:54,582> DEBUG (JdbcTransaction.java:101) [http-nio-8080-exec-5] (org.apache.ibatis.transaction.jdbc.JdbcTransaction) - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@6035a0a9]

<2020-10-15 21:50:54,591> DEBUG (BaseJdbcLogger.java:137) [http-nio-8080-exec-5] (com.bjsxt.mapper.UsersMapper.selectByExample_COUNT) - ==> Preparing: SELECT count(0) FROM users

<2020-10-15 21:50:54,642> DEBUG (BaseJdbcLogger.java:137) [http-nio-8080-exec-5] (com.bjsxt.mapper.UsersMapper.selectByExample_COUNT) - ==> Parameters:

<2020-10-15 21:50:54,685> DEBUG (BaseJdbcLogger.java:137) [http-nio-8080-exec-5] (com.bjsxt.mapper.UsersMapper.selectByExample_COUNT) - <== Total: 1

<2020-10-15 21:50:54,701> DEBUG (BaseJdbcLogger.java:137) [http-nio-8080-exec-5] (com.bjsxt.mapper.UsersMapper.selectByExample) - ==> Preparing: select userid, username, usersex from users LIMIT ?

<2020-10-15 21:50:54,701> DEBUG (BaseJdbcLogger.java:137) [http-nio-8080-exec-5] (com.bjsxt.mapper.UsersMapper.selectByExample) - ==> Parameters: 2(Integer)

org.apache.jasper.JasperException: 无法在web.xml或使用此应用程序部署的jar文件中解析绝对uri：[http://java.sun.com/jsp/jstl/core]

at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:55)

at org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:294)

at org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:81)

at org.apache.jasper.compiler.TagLibraryInfoImpl.generateTldResourcePath(TagLibraryInfoImpl.java:251)

<2020-10-15 21:50:54,704> DEBUG (BaseJdbcLogger.java:137) [http-nio-8080-exec-5] (com.bjsxt.mapper.UsersMapper.selectByExample) - <== Total: 2

<2020-10-15 21:50:54,734> DEBUG (JdbcTransaction.java:123) [http-nio-8080-exec-5] (org.apache.ibatis.transaction.jdbc.JdbcTransaction) - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@6035a0a9]

<2020-10-15 21:50:54,735> DEBUG (JdbcTransaction.java:91) [http-nio-8080-exec-5] (org.apache.ibatis.transaction.jdbc.JdbcTransaction) - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@6035a0a9]

<2020-10-15 21:50:54,736> DEBUG (PooledDataSource.java:391) [http-nio-8080-exec-5] (org.apache.ibatis.datasource.pooled.PooledDataSource) - Returned connection 1614127273 to pool.

at org.apache.jasper.compiler.TagLibraryInfoImpl.<init>(TagLibraryInfoImpl.java:122)

at org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:431)

at org.apache.jasper.compiler.Parser.parseDirective(Parser.java:489)

at org.apache.jasper.compiler.Parser.parseElements(Parser.java:1445)

at org.apache.jasper.compiler.Parser.parse(Parser.java:144)

at org.apache.jasper.compiler.ParserController.doParse(ParserController.java:244)

at org.apache.jasper.compiler.ParserController.parse(ParserController.java:105)

at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:206)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:386)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:362)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:346)

at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:605)

at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:400)

at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)

at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)

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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712)

at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459)

at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:384)

at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312)

at com.bjsxt.web.servlet.UsersServlet.findUsers(UsersServlet.java:91)

at com.bjsxt.web.servlet.UsersServlet.doPost(UsersServlet.java:36)

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 com.bjsxt.web.filter.OpenSessionInViewFilter.doFilter(OpenSessionInViewFilter.java:29)

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:541)

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:690)

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:373)

at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)

at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.base/java.lang.Thread.run(Thread.java:832)

15-Oct-2020 21:50:55.474 信息 [Catalina-utility-2] org.apache.catalina.startup.HostConfig.deployDirectory 把web 应用程序部署到目录 [D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34\webapps\manager]

15-Oct-2020 21:50:55.576 信息 [Catalina-utility-2] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\Tomcat\apache-tomcat-9.0.34-windows-x64\apache-tomcat-9.0.34\webapps\manager] has finished in [102] ms

且客户端浏览器无法加载showUsers.jsp

如果去掉 taglib 指令标签

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

则forEach关键字不报错

此时启动Tomcat可以加载到showUsers.jsp但是不显示数据

我在网上查到了一个解决办法但是不敢乱来，还是想听听老师的意见

以下是源码

UsersServlet

package com.bjsxt.web.servlet;

import com.bjsxt.pojo.Users;
import com.bjsxt.pojo.UsersExample;
import com.bjsxt.service.UsersService;
import com.bjsxt.service.impl.UsersServiceImpl;
import com.github.pagehelper.PageInfo;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/usersServlet.do")
public class UsersServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        /*设置请求编码格式*/
        req.setCharacterEncoding("utf-8");

        /*设置响应编码格式*/
        resp.setContentType("text/html;charset=utf-8");

        String flag = req.getParameter("flag");
        if("addUsers".equals(flag)){
            this.addUsers(req,resp);
        }else if("findUsers".equals(flag)){
            this.findUsers(req,resp);
        }
    }

    private void addUsers(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //获取用户提交数据
        Users users = this.createUsers(req);

        //实例化业务层对象
        UsersService usersService = new UsersServiceImpl();
        usersService.addUsers(users);

        //为避免重复提交，使用重定向到成功页面
        resp.sendRedirect("ok.jsp");

    }

    /**
     * 获取用户提交的信息
     */
    private Users createUsers(HttpServletRequest req) {

        String username = req.getParameter("username");
        String usersex = req.getParameter("usersex");

        Users users = new Users();
        users.setUsername(username);
        users.setUsersex(usersex);

        return users;
    }

    /**
     * 查询用户
     */
    private void findUsers(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取用户提交的数据
        Users users = this.createUsers(req);
        //获取当前页
        String pageIndex = req.getParameter("pageIndex");
        int page = 1;
        if (pageIndex != null && pageIndex.length() > 0) {
            //强转
            page = Integer.parseInt(pageIndex);
        }
        UsersService usersService = new UsersServiceImpl();
        PageInfo<Users> pageInfo = usersService.findUsers(page, users);

        //传递数据
        req.setAttribute("pageInfo", pageInfo);
        //为了避免魔鬼查询得维持住查询条件得把封装了查询条件的users对象一起传过去
        req.setAttribute("users", users);

        //有数据传递得用请求转发
        req.getRequestDispatcher("showUsers.jsp").forward(req,resp);

    }

}

UsersServiceImpl

package com.bjsxt.service.impl;

import com.bjsxt.mapper.UsersMapper;
import com.bjsxt.pojo.Users;
import com.bjsxt.pojo.UsersExample;
import com.bjsxt.service.UsersService;
import com.bjsxt.utils.MybatisUtils;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.apache.ibatis.session.SqlSession;

import java.util.List;

public class UsersServiceImpl implements UsersService {

    @Override
    public void addUsers(Users users) {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        //通过getMapper()方法获取UsersMapper接口实现类的代理对象
        UsersMapper mapper = sqlSession.getMapper(UsersMapper.class);
        mapper.insertSelective(users);
    }

    /**
     * 查询用户
     * @param page
     * @param users
     * @return
     */
    @Override
    public PageInfo<Users> findUsers(int page, Users users) {
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        //通过getMapper()方法获取UsersMapper接口实现类的代理对象
        UsersMapper mapper = sqlSession.getMapper(UsersMapper.class);
        //获取条件
        UsersExample usersExample = this.createUsersExample(users);

        PageHelper.startPage(page, 2);

        List<Users> list = mapper.selectByExample(usersExample);

        //将list放到pageInfo中      pageInfo:封装了基于分页查询得到的结果集的实体类
        PageInfo<Users> pageInfo = new PageInfo<>(list);

        return pageInfo;
    }

    /**
     * 生成查询条件
     */
    private UsersExample createUsersExample(Users users){
        UsersExample usersExample = new UsersExample();
        UsersExample.Criteria criteria = usersExample.createCriteria();
        if(users.getUsername() != null && users.getUsername().length() > 0){
            criteria.andUsernameEqualTo(users.getUsername());
        }
        if(users.getUsersex() != null && users.getUsersex().length() > 0){
            criteria.andUsersexEqualTo(users.getUsersex());
        }

        return usersExample;
    }

}

showUsers.jsp

<%--
  Created by IntelliJ IDEA.
  User: admin
  Date: 2020/10/15
  Time: 19:54
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>显示查询结果</title>
</head>
<body>
<table align="center" border="1" width="40%">
    <tr>
        <th>用户 ID</th>
        <th>用户姓名</th>
        <th>用户性别</th>
    </tr>
    <c:forEach items="${pageInfo.list}" var="users">
        <tr>
            <td>${users.userid}</td>
            <td>${users.username}</td>
            <td>${users.usersex}</td>
        </tr>
    </c:forEach>
</table>
</body>
</html>

求老师指点我该怎么解决

JAVA 全系列/第六阶段：项目管理与SSM框架/Mybatis 34057楼

每次都只能启动一个客户端，再开一个就显示服务器端显示重新建立了连接

JAVA 全系列/第二阶段：JAVA 基础深化和提高/网络编程（旧） 34058楼

老师，请问，用图形化界面开启debug以后，这里为什么多了一个Flask(app.py)(1)呢，而且右键run也是运行的这个，debug不起作用，

但是如果点击这里的三角形符号来运行，debug又是起作用的，那开启debug以后只能通过点击这里运行程序了吗

Python 全系列/第八阶段：轻量级Web开发利器-Flask框架/Flask视图基础和URL 34059楼

将”sxtsxtsxtsxtsxt”字符串中所有的s输出，

如果是不规则的，譬如”sxsxtxtstsxt”字符串中所有的s输出，该怎么做

Python 全系列/第一阶段：Python入门/编程基本概念 34060楼

数据结构中，链表结构里的节点和结点有啥区别

JAVA 全系列/第二阶段：JAVA 基础深化和提高/数据结构 34061楼

老师我这里中文和英文查询的两种方式都使用了，结果还是告诉我是无效的月份，这该怎么解决，hire_date里面的各种格式我也都试了，也都不行hire_date 是这样的

JAVA 全系列/第三阶段：数据库编程/SQL 语言 34062楼

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        
        <link rel="stylesheet" type="text/css" href="css/new_file.css"/>
        
    </head>
    <body>
        
        
        <div class="nav">

        </div>
    </body>
</html>

.nav{
    
    height: 30px;
    
    background-color: gray;
}

老师这是哪里有问题呀

JAVA 全系列/第四阶段：网页编程和设计/CSS3（旧） 34063楼

<!DOCTYPE html>

<head>

<style>

body {

height: 4000px;

}

</style>

</head>

<body>

function showScrollTop() {

var scrollTop = document.documentElement.scrollTop;

console.log(scrollTop);

}

function debounce(fn, delay) {

var timer = null;

return function() {

if (timer) {

clearTimeout(timer);

}

timer = setTimeout(fn, delay);

}

window.addEventListener('scroll', debounce(showScrollTop, 300));

</script>

</body>

</html>

闭包我是理解的，可是这个函数为什么不是从var timer=null开始执行？

WEB前端全系列/第二阶段：JavaScript编程模块/浏览器模型(BOM) 34064楼

我在反复画窗口的时候会出现闪烁白屏是怎么回事。

JAVA 全系列/第一阶段：JAVA 快速入门/飞机大战小项目训练 34065楼

同学您好