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MyBatis(10)逆向工程

什麼是逆向工程? 在學習的過程中會發現,需要我們寫大量的sql語句 此時mybaatis官方為我們提供逆向工程可以針對單表自動生成的mybatis執行所需要的程式碼 使用方法:    MyBatis Generator (MBG) can be run in the following ways: 推薦使用紅色的方法 jar包

官方文件在解壓後的doc檔案中點選index.html

簡單的講解一下:

MyBatis GeneratorXML Configuration File Reference

  建立新的工程: 匯入需要加入的jar   在config檔案下的 gengeratorConfig.xml  基本上都是固定的格式,不需要懂,只許看看懂紅色部分的註釋,以及相關標籤的意義。
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
  PUBLIC 
"-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd"> <generatorConfiguration> <context id="testTables" targetRuntime="MyBatis3"> <commentGenerator> <!-- 是否去除自動生成的註釋 true:是 : false:否 --> <property name="suppressAllComments" value="true" /> </commentGenerator> <!--資料庫連線的資訊:驅動類、連線地址、使用者名稱、密碼 -->
<jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3307/shopping" userId="root" password="1234"> </jdbcConnection> <!-- 預設false,把JDBC DECIMAL 和 NUMERIC 型別解析為 Integer,為 true時把JDBC DECIMAL 和 NUMERIC 型別解析為java.math.BigDecimal --> <javaTypeResolver> <property name="forceBigDecimals" value="false" /> </javaTypeResolver> <!-- targetProject:生成PO類的位置 --> <javaModelGenerator targetPackage="com.MrChengs.po" targetProject=".\src"> <!-- enableSubPackages:是否讓schema作為包的字尾 --> <property name="enableSubPackages" value="false" /> <!-- 從資料庫返回的值被清理前後的空格 --> <property name="trimStrings" value="true" /> </javaModelGenerator> <!-- targetProject:mapper對映檔案生成的位置 --> <sqlMapGenerator targetPackage="com.MrChengs.mapper" targetProject=".\src"> <!-- enableSubPackages:是否讓schema作為包的字尾 --> <property name="enableSubPackages" value="false" /> </sqlMapGenerator> <!-- targetPackage:mapper介面生成的位置 --> <javaClientGenerator type="XMLMAPPER" targetPackage="com.MrChengs.mapper" targetProject=".\src"> <!-- enableSubPackages:是否讓schema作為包的字尾 --> <property name="enableSubPackages" value="false" /> </javaClientGenerator> <!-- 指定資料庫表 --> <table tableName="items"></table> <table tableName="orders"></table> <table tableName="orderdetail"></table> <table tableName="user"></table> </context> </generatorConfiguration>
test目錄下 GeneratorSqlmap.java
public class GeneratorSqlmap {
     public void generator() throws Exception{
           List<String> warnings = new ArrayList<String>();
           boolean overwrite = true;
           //指定 逆向工程配置檔案
           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();
           }
     }
}
都是固定的格式,固體的可以參考官方的文件。 然後執行在 簡單說明一下 如下的註釋 首先是表 其次是表中的欄位
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"
重新整理觀察 com.MrChengs.po com.MrCehngs.mapper 兩個包裡面的檔案 此時的檔案我們得到了,在使用的時候我們不要進行對原有的程式碼的修改。  返回上一個博文將進行簡單的小案例測試:  

複製圖中的檔案到本工程中

 新建測試類
public class test {
     private ApplicationContext applicationContext;
     
     public ApplicationContext getApplication(){
           applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
           return applicationContext;
     }
     
     //根據主鍵id進行查詢
     @Test
     public void test() {
           
           ItemsMapper items = (ItemsMapper) getApplication().getBean("itemsMapper");
           
           Items it = items.selectByPrimaryKey(1);
           System.out.println(it.toString());
     }
     //自定義查詢條件
     @Test
     public void test1() {
           ItemsMapper itemsMapperems = (ItemsMapper) getApplication().getBean("itemsMapper");
           
           ItemsExample itemsExample = new ItemsExample();
           //通過criteria構造條件查詢
           ItemsExample.Criteria criteria = itemsExample.createCriteria();
           criteria.andNameEqualTo("筆記本");
           //可能返回多個記錄
           List<Items> items = itemsMapperems.selectByExample(itemsExample);
           
           System.out.println(items);
           }
}
  均可以測試成功!! 對於其他的方法,在使用的時候,可以參考自動生成的原始碼進行測試,都是可以測試成功的!  逆向工程的使用極大的方便我們進行開發,作為程式設計師不需要過多的關注這個,我們進行了解基本的使用和用法即可。 其餘的增刪改除,可以進行測試,在不會使用的情況下,可以參考原始碼,原始碼是之前的前幾章節的內容.