user 表 CRUD 实战

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package demo.mp;
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import org.apache.ibatis.session.SqlSession;
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import org.apache.ibatis.session.SqlSessionFactory;
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public class CrudDemo {
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    public static void main(String[] args) {
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        SqlSessionFactory factory = Mp.factory();
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        try (SqlSession session = factory.openSession(true)) {
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            UserMapper mapper = session.getMapper(UserMapper.class);
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            User frank = new User("frank", "frank@example.com", 1);
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            mapper.insert(frank);
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            System.out.println("insert id=" + frank.getId());
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            User loaded = mapper.selectById(frank.getId());
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            System.out.println("selectById: " + loaded);
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            loaded.setEmail("frank.new@example.com");
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            mapper.updateById(loaded);
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            System.out.println("after update: " + mapper.selectById(frank.getId()));
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            System.out.println("total users=" + mapper.selectList(null).size());
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            mapper.deleteById(frank.getId());
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            System.out.println("deleted, exists=" + (mapper.selectById(frank.getId()) == null));
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        }
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    }
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}