pager的getFirstParam为什么写成pager.firstParam?

是哪里做了转换吗？依据是什么？

为什么我的会报如下错误？

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E:\tomcat\bin\catalina.bat run
[2018-10-02 01:40:58,719] Artifact shopmgr1:war exploded: Waiting for server connection to start artifact deployment...
Using CATALINA_BASE:   "C:\Users\Administrator\.IntelliJIdea2018.1\system\tomcat\Unnamed_shopmgr1"
Using CATALINA_HOME:   "E:\tomcat"
Using CATALINA_TMPDIR: "E:\tomcat\temp"
Using JRE_HOME:        "C:\Program Files\Java\jdk1.8.0_171"
Using CLASSPATH:       "E:\tomcat\bin\bootstrap.jar;E:\tomcat\bin\tomcat-juli.jar"
02-Oct-2018 13:41:00.731 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server version:        Apache Tomcat/8.5.32
02-Oct-2018 13:41:00.738 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server built:          Jun 20 2018 19:50:35 UTC
02-Oct-2018 13:41:00.738 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Server number:         8.5.32.0
02-Oct-2018 13:41:00.738 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS Name:               Windows 7
02-Oct-2018 13:41:00.738 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log OS Version:            6.1
02-Oct-2018 13:41:00.738 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Architecture:          amd64
02-Oct-2018 13:41:00.739 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Java Home:             C:\Program Files\Java\jdk1.8.0_171\jre
02-Oct-2018 13:41:00.739 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Version:           1.8.0_171-b11
02-Oct-2018 13:41:00.739 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Vendor:            Oracle Corporation
02-Oct-2018 13:41:00.739 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_BASE:         C:\Users\Administrator\.IntelliJIdea2018.1\system\tomcat\Unnamed_shopmgr1
02-Oct-2018 13:41:00.740 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_HOME:         E:\tomcat
02-Oct-2018 13:41:00.741 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.config.file=C:\Users\Administrator\.IntelliJIdea2018.1\system\tomcat\Unnamed_shopmgr1\conf\logging.properties
02-Oct-2018 13:41:00.741 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
02-Oct-2018 13:41:00.741 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcom.sun.management.jmxremote=
02-Oct-2018 13:41:00.742 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcom.sun.management.jmxremote.port=1099
02-Oct-2018 13:41:00.742 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcom.sun.management.jmxremote.ssl=false
02-Oct-2018 13:41:00.742 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcom.sun.management.jmxremote.authenticate=false
02-Oct-2018 13:41:00.744 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.rmi.server.hostname=127.0.0.1
02-Oct-2018 13:41:00.744 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djdk.tls.ephemeralDHKeySize=2048
02-Oct-2018 13:41:00.744 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.protocol.handler.pkgs=org.apache.catalina.webresources
02-Oct-2018 13:41:00.746 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dignore.endorsed.dirs=
02-Oct-2018 13:41:00.746 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.base=C:\Users\Administrator\.IntelliJIdea2018.1\system\tomcat\Unnamed_shopmgr1
02-Oct-2018 13:41:00.747 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.home=E:\tomcat
02-Oct-2018 13:41:00.747 信息 [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.io.tmpdir=E:\tomcat\temp
02-Oct-2018 13:41:00.747 信息 [main] org.apache.catalina.core.AprLifecycleListener.lifecycleEvent The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [C:\Program Files\Java\jdk1.8.0_171\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Java\jdk1.8.0_171;E:\imooc资料\apache-maven-3.5.4\bin;C:\Program Files\MySQL\MySQL Server 8.0\bin;.]
02-Oct-2018 13:41:01.033 信息 [main] org.apache.coyote.AbstractProtocol.init Initializing ProtocolHandler ["http-nio-8080"]
02-Oct-2018 13:41:01.065 信息 [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read
02-Oct-2018 13:41:01.081 信息 [main] org.apache.coyote.AbstractProtocol.init Initializing ProtocolHandler ["ajp-nio-8009"]
02-Oct-2018 13:41:01.085 信息 [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read
02-Oct-2018 13:41:01.086 信息 [main] org.apache.catalina.startup.Catalina.load Initialization processed in 1107 ms
02-Oct-2018 13:41:01.143 信息 [main] org.apache.catalina.core.StandardService.startInternal Starting service [Catalina]
02-Oct-2018 13:41:01.143 信息 [main] org.apache.catalina.core.StandardEngine.startInternal Starting Servlet Engine: Apache Tomcat/8.5.32
02-Oct-2018 13:41:01.164 信息 [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8080"]
02-Oct-2018 13:41:01.197 信息 [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-8009"]
02-Oct-2018 13:41:01.202 信息 [main] org.apache.catalina.startup.Catalina.start Server startup in 115 ms
Connected to server
[2018-10-02 01:41:01,468] Artifact shopmgr1:war exploded: Artifact is being deployed, please wait...
02-Oct-2018 13:41:05.017 信息 [RMI TCP Connection(2)-127.0.0.1] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
log4j:WARN No appenders could be found for logger (org.springframework.web.context.ContextLoader).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
[2018-10-02 01:41:07,953] Artifact shopmgr1:war exploded: Artifact is deployed successfully
[2018-10-02 01:41:07,953] Artifact shopmgr1:war exploded: Deploy took 6,485 milliseconds
02-Oct-2018 13:41:11.167 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [E:\tomcat\webapps\manager]
02-Oct-2018 13:41:11.467 信息 [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [E:\tomcat\webapps\manager] has finished in [298] ms
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org.springframework.jdbc.BadSqlGrammarException: 
### Error querying database.  Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LIMIT 0,3' at line 2
### The error may exist in com/imooc/shop/repository/ArticleMapper.xml
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: select * from ec_article          WHERE LIMIT ?,?
### Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LIMIT 0,3' at line 2
; bad SQL grammar []; nested exception is java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LIMIT 0,3' at line 2
    at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:231)
    at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:73)
    at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:371)
    at com.sun.proxy.$Proxy14.selectList(Unknown Source)
    at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:198)
    at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:119)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:63)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52)
    at com.sun.proxy.$Proxy19.searchArticles(Unknown Source)
    at com.imooc.shop.service.ShopServiceImpl.searchArticles(ShopServiceImpl.java:71)
    at com.imooc.shop.action.ListServlet.getAll(ListServlet.java:75)
    at com.imooc.shop.action.ListServlet.service(ListServlet.java:46)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:800)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1471)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LIMIT 0,3' at line 2
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:975)
    at com.mysql.cj.jdbc.ClientPreparedStatement.execute(ClientPreparedStatement.java:392)
    at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.execute(NewProxyPreparedStatement.java:1392)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:62)
    at com.sun.proxy.$Proxy22.execute(Unknown Source)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:59)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:73)
    at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:60)
    at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:267)
    at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:137)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:96)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:77)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:108)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:102)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:358)
    ... 32 more

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 
<mapper namespace="com.imooc.shop.repository.ArticleMapper">
 
    <select id="searchArticles" resultType="Article">
        <!--别名配置 ，是由spring配置得到简化的，否则要写全路径-->
        select * from ec_article
        <where>
            <if test="typeCode!=null&amp;&amp;typeCode!=''">
                and TYPE_CODE like CONCAT("",#{typeCode},"%")
            </if>
            <if test="secondType!=null&amp;&amp;secondType!=''">
                and TYPE_CODE =#{secondType}
            </if>
            <if test="title!=null&amp;&amp;title!=''">
                and title like CONCAT("%",#{title},"%")
            </if>
            LIMIT #{pager.firstParam},#{pager.pageSize}
        </where>
 
    </select>
 
    <select id="count" resultType="int">
        <!--别名配置 ，是由spring配置得到简化的，否则要写全路径-->
        select count(*) from ec_article
        <where>
            <if test="typeCode!=null&amp;&amp;typeCode!=''">
                and TYPE_CODE like CONCAT("",#{typeCode},"%")
            </if>
            <if test="secondType!=null&amp;&amp;secondType!=''">
                and TYPE_CODE =#{secondType}
            </if>
            <if test="title!=null&amp;&amp;title!=''">
                and title like CONCAT("%",#{title},"%")
            </if>
 
        </where>
 
    </select>
 
</mapper>

package com.imooc.shop.repository;
 
import com.imooc.shop.bean.Article;
import com.imooc.shop.bean.ArticleType;
import com.imooc.shop.utils.Pager;
import org.apache.ibatis.annotations.Param;
 
import java.util.List;
 
public interface ArticleMapper {
 
 
    List<Article> searchArticles(@Param("typeCode")String typeCode,@Param("secondType") String secondType,@Param("title") String title,
    @Param("pager")Pager pager);
 
    int count(@Param("typeCode")String typeCode,@Param("secondType") String secondType,@Param("title") String title);
}

广州麻辣牛杂档 2018-10-02

源自：项目：电商模块开发 4-4 商品分页开发

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4回答

慕布斯645313 2018-10-07 11:38:07

你可以在pager类中定义一个firstParam属性试一试，看看添加该属性之后是否不报错了。

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提问者广州麻辣牛杂档 2018-10-05 09:36:19

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似乎有点意思 2018-10-03 19:02:37

### Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LIMIT 0,3' at line 2

; bad SQL grammar []; nested exception is java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'LIMIT 0,3' at line 2

看异常信息,问题出在sql语句的limit部分

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似乎有点意思 2018-10-03 17:19:57

定义一个int变量firstParam

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提问者广州麻辣牛杂档 #1

是哪里定义了

2018-10-04 10:56:41
似乎有点意思回复提问者广州麻辣牛杂档 #2

pager.firstParam的get方法就是getFirstParam,由此看来应该是在Pager类中定义了private int firstParam;

2018-10-04 11:39:56
提问者广州麻辣牛杂档回复似乎有点意思 #3

哥们，一开始我也这么认为，可是真的没有，我翻看了视频和源文件没有的。所以觉得奇怪

2018-10-05 09:35:56