谈谈mybatis-generaator的使用

    现在毕竟是ssm的统领，关于框架的设计，一般采用dao层的单独增删改查，一般不会把存在外键的处理放在dao，把复杂的逻辑放在service层，除非很有必要要在数据库层限制数据的处理之外，才会设置外键。

    针对于mybatis的xml写得可能会很烦，也很容易出错，那么我们就很有必要有工具进行处理，接下来，我们就使用基于maven的插件工具进行处理。

                org.mybatis.generator
                mybatis-generator-maven-plugin
                1.3.2
                
                    src/main/resources/generatorConfig.xml
                    true
                    true
                
                
                    
                        Generate MyBatis Artifacts
                        
                            generate
                        
                    
                

以上pom.xml文件的configurationFile配置文件的路径

    对于一些文章可能并未指出这个生成工具是否能够生成存在外键关系的多表查询，其实是不行的，这也是我为什么开头会介绍关于dao以及service设计的原因，不过我依旧会觉得这个工具还不够方便，待我功力够了，看看能否做个生成工具，解决这个问题。接着是属性文件generator.properties

   

jdbc.driverLocation=C:\\JSP\\mysql-connector-java-5.1.39\\mysql-connector-java-5.1.39\\mysql-connector-java-5.1.39-bin.jar
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.connectionURL=jdbc\:mysql\://localhost/guihuashi
jdbc.userId=root
jdbc.password=

    我采用的是itellij来开发的，需要配置运行。点击Run按钮，选择Edit Configurations，点击 " + " 按钮，选择maven

在Name中填入名字，接着在Command line填写mybatis-generator:generate -e这样我们点击apply按钮，就会看到按钮

点击运行，那么我们来看看控制台会出现什么情况?

C:\dazaijava\java\jdk1.8.0_20\bin\java -Dmaven.multiModuleProjectDirectory=C:\源码\zookeeper_java "-Dmaven.home=C:\JetBrains\IntelliJ IDEA 2016.3最新版\plugins\maven\lib\maven3" "-Dclassworlds.conf=C:\JetBrains\IntelliJ IDEA 2016.3最新版\plugins\maven\lib\maven3\bin\m2.conf" -Didea.launcher.port=7532 "-Didea.launcher.bin.path=C:\JetBrains\IntelliJ IDEA 2016.3最新版\bin" -Dfile.encoding=UTF-8 -classpath "C:\JetBrains\IntelliJ IDEA 2016.3最新版\plugins\maven\lib\maven3\boot\plexus-classworlds-2.5.2.jar;C:\JetBrains\IntelliJ IDEA 2016.3最新版\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain org.codehaus.classworlds.Launcher -Didea.version=2016.3 mybatis-generator:generate -e
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for zookeeper_java:zookeeper_java:jar:1.0-SNAPSHOT
[WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.apache.httpcomponents:httpclient:jar -> duplicate declaration of version 4.0.2 @ line 121, column 21
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING] 
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building zookeeper_java 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- mybatis-generator-maven-plugin:1.3.2:generate (default-cli) @ zookeeper_java ---
[INFO] Connecting to the Database
Tue Dec 27 12:52:22 CST 2016 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.
[INFO] Introspecting table guihuashi.stu
log4j:WARN No appenders could be found for logger (org.mybatis.generator.internal.db.DatabaseIntrospector).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
[INFO] Introspecting table guihuashi.info
[INFO] Generating Example class for table stu
[INFO] Generating Record class for table stu
[INFO] Generating Mapper Interface for table stu
[INFO] Generating SQL Map for table stu
[INFO] Generating Example class for table info
[INFO] Generating Record class for table info
[INFO] Generating Mapper Interface for table info
[INFO] Generating SQL Map for table info
[INFO] Saving file StuMapper.xml
[INFO] Saving file InfoMapper.xml
[INFO] Saving file StuExample.java
[INFO] Saving file Stu.java
[INFO] Saving file StuMapper.java
[INFO] Saving file InfoExample.java
[INFO] Saving file Info.java
[INFO] Saving file InfoMapper.java
[WARNING] Column PLAN_ID, specified to be ignored in table stu, does not exist in the table.
[WARNING] Root class com.foo.louis.Hello cannot be loaded, checking for member overrides is disabled for this class 
[WARNING] Existing file C:\源码\zookeeper_java\src\main\java\org\louis\hometutor\po\StuExample.java was overwritten
[WARNING] Existing file C:\源码\zookeeper_java\src\main\java\org\louis\hometutor\po\Stu.java was overwritten
[WARNING] Existing file C:\源码\zookeeper_java\src\main\java\com\foo\tourist\dao\StuMapper.java was overwritten
[WARNING] Existing file C:\源码\zookeeper_java\src\main\java\org\louis\hometutor\po\InfoExample.java was overwritten
[WARNING] Existing file C:\源码\zookeeper_java\src\main\java\org\louis\hometutor\po\Info.java was overwritten
[WARNING] Existing file C:\源码\zookeeper_java\src\main\java\com\foo\tourist\dao\InfoMapper.java was overwritten
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 8.660 s
[INFO] Finished at: 2016-12-27T12:52:24+08:00
[INFO] Final Memory: 6M/19M
[INFO] ------------------------------------------------------------------------

Process finished with exit code 0

编译成功success，而且我们会在工程里面看到生成的mybatis文件，大功告成，如果编译不成功，根据控制台解决。