**1.UserMapper.java** ~~~ //根據用戶名模糊查詢 List<User> findByNameLike(String name); ~~~ **2.UserMapper.xml** **方式一，使用#{}** ~~~ <!--模糊查詢--> <select id="findByNameLike" resultMap="userMapper"> select * from t_user where u_name like #{name} </select> ~~~ 測試代碼 ~~~ @Test public void testFindByNameLike(){ UserMapper mapper = session.getMapper(UserMapper.class); System.out.println(mapper.findByNameLike("%no%")); } ~~~ **方式二，使用${}** UserMapper.xml ~~~ <select id="findByNameLike" resultMap="userMapper"> select * from t_user where u_name like '%${name}%' </select> ~~~ **測試代碼** ~~~ @Test public void testFindByNameLike2(){ UserMapper mapper = session.getMapper(UserMapper.class); System.out.println(mapper.findByNameLike("no")); } ~~~ 小結 1\. #{}代表占位符, ${}代表字符串拼接 2\. #{}是生成預編譯sql,執行效率高 3\. ${}每次都需要重新編譯,效率較低 4\. #{}不會出現sql注入問題,${}會出現sql注入問題 5\. #{}可接受的參數類型相對較多.${}只能接受字符串類型.