什么是逆向工程？
在学习的过程中会发现，需要我们写大量的sql语句
此时mybaatis官方为我们提供逆向工程可以针对单表自动生成的mybatis执行所需要的代码
使用方法：
MyBatis Generator (MBG) can be run in the following ways:
From the command prompt with an XML configuration
As an Ant task with an XML configuration
As a Maven Plugin
From another Java program with an XML configuration
From another Java program with a Java based configuration
推荐使用红色的方法
jar包
官方文档在解压后的doc文件中点击index.html
简单的讲解一下：
MyBatis GeneratorXML Configuration File Reference
建立新的工程：
导入需要加入的jar
在config文件下的
gengeratorConfig.xml
基本上都是固定的格式，不需要懂，只许看看懂红色部分的注释，以及相关标签的意义。
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test目录下
GeneratorSqlmap.java
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public class GeneratorSqlmap {
public void generator() throws Exception{
List
warnings = new ArrayList();
boolean overwrite = true;
//指定 逆向工程配置文件
File configFile = new File("config/generatorConfig.xml");
ConfigurationParser cp = new ConfigurationParser(warnings);
Configuration config = cp.parseConfiguration(configFile);
DefaultShellCallback callback = new DefaultShellCallback(overwrite);
MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,
callback, warnings);
myBatisGenerator.generate(null);
}
public static void main(String[] args) throws Exception {
try {
GeneratorSqlmap generatorSqlmap = new GeneratorSqlmap();
generatorSqlmap.generator();
} catch (Exception e) {
e.printStackTrace();
}
}
}
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都是固定的格式，固体的可以参考官方的文档。
然后运行在
简单说明一下
如下的注释
首先是表
其次是表中的字段
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2018-10-25 16:04:22,837 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Retrieving column information for table "items"
2018-10-25 16:04:22,848 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "id", data type 4, in table "shopping..items"
2018-10-25 16:04:22,849 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "name", data type 12, in table "shopping..items"
2018-10-25 16:04:22,849 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "price", data type 7, in table "shopping..items"
2018-10-25 16:04:22,849 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "detail", data type -1, in table "shopping..items"
2018-10-25 16:04:22,849 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "pic", data type 12, in table "shopping..items"
2018-10-25 16:04:22,849 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "createtime", data type 93, in table "shopping..items"
2018-10-25 16:04:22,855 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Retrieving column information for table "orders"
2018-10-25 16:04:22,859 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "id", data type 4, in table "shopping..orders"
2018-10-25 16:04:22,859 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "user_id", data type 4, in table "shopping..orders"
2018-10-25 16:04:22,859 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "number", data type 12, in table "shopping..orders"
2018-10-25 16:04:22,859 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "createtime", data type 93, in table "shopping..orders"
2018-10-25 16:04:22,859 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "note", data type 12, in table "shopping..orders"
2018-10-25 16:04:22,864 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Retrieving column information for table "orderdetail"
2018-10-25 16:04:22,868 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "id", data type 4, in table "shopping..orderdetail"
2018-10-25 16:04:22,868 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "orders_id", data type 4, in table "shopping..orderdetail"
2018-10-25 16:04:22,868 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "items_id", data type 4, in table "shopping..orderdetail"
2018-10-25 16:04:22,868 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "items_num", data type 4, in table "shopping..orderdetail"
2018-10-25 16:04:22,869 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Retrieving column information for table "user"
2018-10-25 16:04:22,874 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "id", data type 4, in table "shopping..user"
2018-10-25 16:04:22,874 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "username", data type 12, in table "shopping..user"
2018-10-25 16:04:22,874 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "birthday", data type 91, in table "shopping..user"
2018-10-25 16:04:22,874 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "sex", data type 1, in table "shopping..user"
2018-10-25 16:04:22,874 [main] DEBUG [org.mybatis.generator.internal.db.DatabaseIntrospector] - Found column "address", data type 12, in table "shopping..user"
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刷新观察
com.MrChengs.po
com.MrCehngs.mapper
两个包里面的文件
此时的文件我们得到了，在使用的时候我们不要进行对原有的代码的修改。
返回上一个博文将进行简单的小案例测试：
有不懂的可以参考：MyBatis整合Spring
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新建测试类
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public class test {
private ApplicationContext applicationContext;
public ApplicationContext getApplication(){
applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
return applicationContext;
}
//根据主键id进行查询
@Test
public void test() {
ItemsMapper items = (ItemsMapper) getApplication().getBean("itemsMapper");
Items it = items.selectByPrimaryKey(1);
System.out.println(it.toString());
}
//自定义查询条件
@Test
public void test1() {
ItemsMapper itemsMapperems = (ItemsMapper) getApplication().getBean("itemsMapper");
ItemsExample itemsExample = new ItemsExample();
//通过criteria构造条件查询
ItemsExample.Criteria criteria = itemsExample.createCriteria();
criteria.andNameEqualTo("笔记本");
//可能返回多个记录
List items = itemsMapperems.selectByExample(itemsExample);
System.out.println(items);
}
}
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均可以测试成功！！
对于其他的方法，在使用的时候，可以参考自动生成的源码进行测试，都是可以测试成功的！
逆向工程的使用极大的方便我们进行开发，作为程序员不需要过多的关注这个，我们进行了解基本的使用和用法即可。
其余的增删改除，可以进行测试，在不会使用的情况下，可以参考源码，源码是之前的前几章节的内容.
https://www.cnblogs.com/Mrchengs/p/9851117.html
