mybatis-sql builder class-优快云博客

本文介绍了在拼接SQL时遇到的问题及解决方案，并展示了如何使用MyBatis 3的SQL类来提高代码的整洁性和可读性，避免了常见的SQL拼接错误。

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在拼接sql的时候，经常遇到字符串写的太长无法辨别的情况

String sql = "SELECT P.ID, P.USERNAME, P.PASSWORD, P.FULL_NAME, " "P.LAST_NAME,P.CREATED_ON, P.UPDATED_ON " + "FROM PERSON P, ACCOUNT A " + "INNER JOIN DEPARTMENT D on D.ID = P.DEPARTMENT_ID " + "INNER JOIN COMPANY C on D.COMPANY_ID = C.ID " + "WHERE (P.ID = A.ID AND P.FIRST_NAME like ?) " + "OR (P.LAST_NAME like ?) " + "GROUP BY P.ID " + "HAVING (P.LAST_NAME like ?) " + "OR (P.FIRST_NAME like ?) " + "ORDER BY P.ID, P.FULL_NAME";

mybatis3中通过SQLclass使得代码更整洁

private String selectPersonSql() { return new SQL() {{ SELECT("P.ID, P.USERNAME, P.PASSWORD, P.FULL_NAME"); SELECT("P.LAST_NAME, P.CREATED_ON, P.UPDATED_ON"); FROM("PERSON P"); FROM("ACCOUNT A"); INNER_JOIN("DEPARTMENT D on D.ID = P.DEPARTMENT_ID"); INNER_JOIN("COMPANY C on D.COMPANY_ID = C.ID"); WHERE("P.ID = A.ID"); WHERE("P.FIRST_NAME like ?"); OR(); WHERE("P.LAST_NAME like ?"); GROUP_BY("P.ID"); HAVING("P.LAST_NAME like ?"); OR(); HAVING("P.FIRST_NAME like ?"); ORDER_BY("P.ID"); ORDER_BY("P.FULL_NAME"); }}.toString(); }

这种提供的方法不用担心where是否重复,and是否会多的问题

转载于:https://my.oschina.net/iioschina/blog/1858917