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【常見錯誤解決辦法點此標題查看】說下我遇到和能想到的一些錯誤及解決辦法

1) Invalid bound statement (not found)錯誤

檢查文件AreaDao.xml中mapper標簽的namespace屬性的值，正確值為[AreaDao]的全限定名，而不是它的包名

2) java.io.FileNotFoundException: class path resource [classpath*:/mapper/**.xml] cannot be opened because it does not exist錯誤

檢查SessionFactoryConfiguration類中sqlSessionFactoryBean.setMapperLocations的傳值正確為[resolver.getResources]最后的[S]很容易代碼提示的時候選錯選成[resolver.getResource] 兩者區(qū)別在于單文件和多文件。classpath*:/mapper/**.xml 最后的**.xml是該路徑下所有的*.xml文件的寫法所以新手一定要嚴格注意,仔細檢查代碼!!!

3) 關(guān)于mybatis-config.xml配置文件的相關(guān)錯誤

關(guān)于該文件出現(xiàn)的錯誤參考解決思路如下

①請仔細檢查文件的層級! 該文件所處的正確位置應(yīng)為[src/main/resources]下

②檢查xml文件中的約束的正確性(PS:新人有時候往往會迷之自信有些時候看教程手敲代碼不要相信自己的眼睛!!!! 懶人可以復(fù)制下方代碼)

---------------------------------------------------------------------------------------------------------

<?xml?version="1.0"?encoding="UTF-8"??>
<!DOCTYPE?configuration
????????PUBLIC?"-//mybatis.org//DTD?Config?3.0//EN"
????????"http://mybatis.org/dtd/mybatis-3-config.dtd">

---------------------------------------------------------------------------------------------------------

③檢查3個setting標簽的name屬性三個name屬性具體如下可以復(fù)制粘貼原因同上: 不要迷之自信

useGeneratedKeys

useColumnLabel

PS: 此處?useColumnLabel 非常容易寫成?useColumnLable ? Label和Lable 傻傻分不清楚?

mapUnderscoreToCamelCase

如遇到其他問題歡迎反饋追問看到即回復(fù)

最后啰里啰嗦下: 新人很多時候看教程往往回迷之自信這個教程適用于有Spring MVC功底的人學(xué)習(xí)SpringBoot的不完全適應(yīng)新人小白強烈建議深度學(xué)習(xí)Spring 尤其是IOC和AOP方面建議配合源碼學(xué)習(xí)(PS:懂得底層源碼的原理結(jié)構(gòu) 往往可以讓你快速找到解決問題的思路) 遇到BUG不要慌冷靜下來濾清思路往往比干著急要強很多作為一名合格的成年的程序員要學(xué)會控制自己的情緒往往遇到BUG才是最好的一帆風(fēng)順反而對未來不是很好每一次解決BUG的過程才是你真正成長的過程最后希望大家共同進步一起努力向前?

Mr_曉勃

2019-09-12

源自：SpringBoot+MyBatis搭建迷你小程序 3-6

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IT_TI3235192
2019-10-12

java.sql.SQLSyntaxErrorException: Unknown database 'tb_area'

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120) ~[mysql-connector-java-8.0.17.jar:8.0.17]

at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.17.jar:8.0.17]

at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.17.jar:8.0.17]

at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:827) ~[mysql-connector-java-8.0.17.jar:8.0.17]

at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:447) ~[mysql-connector-java-8.0.17.jar:8.0.17]

at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:237) ~[mysql-connector-java-8.0.17.jar:8.0.17]

at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199) ~[mysql-connector-java-8.0.17.jar:8.0.17]

at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2]

at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11]

2019-10-12 16:02:43.073? WARN 9036 --- [HelperThread-#0] c.m.v2.resourcepool.BasicResourcePool? ? : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@68b9190f -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:?

請問您一下，這是什么原因？我完全按照教程來的