增刪改

????Mybatis為我們提供了<insert>、<update>、<delete>標簽來對應(yīng)增刪改操作

在接口中寫增刪改的抽象方法

void?addEmp(Employee?e);??

void?updateEmp(Employee?e);??

void?deleteEmp(Employee?e);??

在映射文件中寫sql語句

<insert?id="addEmp"?parameterType="com.figsprite.bean.Employee">??

????insert?into?tb_employee(last_name,email,gender)??

????values(#{lastName},#{email},#{gender})??

</insert>??

<update?id="updateEmp"?parameterType="com.figsprite.bean.Employee">??

????update?tb_empolyee??

??????set?last_name=#{lastName},email=#{email},gender=#{genser}??

??????where?id=#{id}??

</update>??

<delete?id="deleteEmp"?parameterType="com.figsprite.bean.Employee">??

????delete?from?tb_employee?where?id=#{id}??

</delete>

顧名思義，parameterType就是參數(shù)類型，而我們通過#{字段名}的方式來傳遞對象中的屬性，resultType允許使用String、Boolean等基本類型包作為返回值

測試

@Test??

????public?void?test3()?throws?IOException{??

????????SqlSessionFactory?sqlSessionFactory?=?getSqlSessionFactory();??

????????SqlSession?openSession?=?sqlSessionFactory.openSession();??

????????Employee?e?=?new?Employee();??

????????e.setGender("1");??

????????e.setLastName("Hello");??

????????e.setEmail("qwewqeqw");??

????????e.toString();??

????????try?{??

????????????EmployeeMapper?mapper?=?openSession.getMapper(EmployeeMapper.class);??

????????????mapper.addEmp(e);??

????????????openSession.commit();??

????????}finally?{??

????????????openSession.close();??

????????}??

????}??

?

@Test??

????public?void?test4()?throws?IOException{??

????????SqlSessionFactory?sqlSessionFactory?=?getSqlSessionFactory();??

????????SqlSession?openSession?=?sqlSessionFactory.openSession();??

????????Employee?e?=?new?Employee();??

????????e.setId(1);??

????????e.setGender("0");??

????????e.setEmail("qwq");??

????????e.setLastName("Jerry");??

????????try?{??

????????????EmployeeMapper?mapper?=?openSession.getMapper(EmployeeMapper.class);??

????????????mapper.updateEmp(e);??

????????????openSession.commit();??

????????}finally?{??

????????????openSession.close();??

????????}??

????}??

這里我們要自動提交數(shù)據(jù)，我們也可以選擇SqlSession openSession = sqlSessionFactory.openSession(true); 這樣就不用手動提交了。

@Test??

public?void?test5?()throws?IOException{??

????SqlSessionFactory?sqlSessionFactory?=?getSqlSessionFactory();??

????SqlSession?openSession?=?sqlSessionFactory.openSession();??

????Employee?e?=?new?Employee();??

????e.setId(1);??

????try{??

????????EmployeeMapper?mapper?=?openSession.getMapper(EmployeeMapper.class);??

????????mapper.deleteEmp(e);??

????????openSession.commit();??

????}finally?{??

????????openSession.close();??

????}??

}?

insert獲取自增主鍵值

????我們在上面的例子中可以看到，我們插入時候并沒有指定id，因為我們id是通過自增方式，JDBC里面提供了這樣的方法

ResultSet getGeneratedKeys()

MyBatis也支持，當然它的底層，其實就是這個函數(shù)，我們僅需在<insert>標簽里添加屬性即可

useGeneratedKeys="true"

使用自增主鍵獲取主鍵值策略，接著用keyProperty這個屬性，指定對應(yīng)主鍵屬性，也就是Mybatis獲取到逐漸使以后將它賦給JavaBean的對應(yīng)屬性

<insert?id="addEmp"?parameterType="com.figsprite.bean.Employee"??

????useGeneratedKeys="true"?keyProperty="id">??

讓我們做個測試

@Test??

public?void?test3()?throws?IOException{??

????SqlSessionFactory?sqlSessionFactory?=?getSqlSessionFactory();??

????SqlSession?openSession?=?sqlSessionFactory.openSession();??

????Employee?e?=?new?Employee();??

????e.setGender("1");??

????e.setLastName("Hello");??

????e.setEmail("qwewqeqw");??

????e.toString();??

????try?{??

????????EmployeeMapper?mapper?=?openSession.getMapper(EmployeeMapper.class);??

????????mapper.addEmp(e);??

????????openSession.commit();??

????????System.out.println(e.getId());??

????}finally?{??

????????openSession.close();??

????}??

}?

如果我們沒有寫useGenerateKeys和KeyProperty，那么上述代碼打印出來的將會是null

?

轉(zhuǎn)載于:https://www.cnblogs.com/figsprite/p/10733000.html

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