Day28——MyBatis动态SQL trim

曾经终败给现在 2023-07-04 15:34 1阅读 0赞

# 一. 知识储备 #

EmployeeMapperDynamicSQL.java

package com.atguigu.mybatis.dao;
    
    import java.util.List;
    
    import com.atguigu.mybatis.beans.Employee;
    
    public interface EmployeeMapperDynamicSQL { 
    
    	
    	public List<Employee> selectEmployeeByConditionTrim(Employee Condition);
    	
    	
    }

EmployeeMapperDynamicSQL.xml

<select id="selectEmployeeByConditionTrim" resultType="com.atguigu.mybatis.beans.Employee">
    	     select id, last_name, email, gender from tbl_employee
             	     
    	     <trim prefix="where" suffixOverrides="and|or">
    		     <if test="id!=null">
    		         id = #{id} and
    		     </if>
    		     <if test="lastName!=null && lastName!=""">
    	  	         last_name = #{lastName} and
    		     </if>
    		     <if test="email!=null and email.trim()!=''">
    		         email = #{email} or
    		     </if>
    		     <if test="gender==0 or gender==1">
    		         gender = #{gender}
    		     </if>
    	     </trim>
    	</select>

TestMyBatisDynamicSQL.java

@Test
    	public void testTrim() throws Exception{ 
    		SqlSessionFactory ssf = getSqlSessionFactory();
    		SqlSession session = ssf.openSession();
    		try { 
    			EmployeeMapperDynamicSQL mapper = session.getMapper(EmployeeMapperDynamicSQL.class);
    			Employee condition = new Employee();
    // condition.setId(1001);
    			condition.setLastName("刚哥");
    // condition.setEmail("gg@sina.com");
    // condition.setGender("1");
    			
    			List<Employee> emps = mapper.selectEmployeeByConditionTrim(condition);
    			System.out.println(emps);
    			
    			session.commit();
    		} finally { 
    			// TODO: handle finally clause
    			session.close();
    		}
    		
    	}