Day30——MyBatis动态SQL choose when otherwise

落日映苍穹つ 2023-07-04 15:39 1阅读 0赞

# 一. 例子 #

EmployeeMapperDynamicSQL.java

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

EmployeeMapperDynamicSQL.xml

<select id="selectEmployeeByConditionChoose" resultType="com.atguigu.mybatis.beans.Employee">
    	      select id, last_name, email, gender from tbl_employee
    	      <where>
    	          <choose>
    	              <when test="id!=null">
    	                  id = #{id}
    	              </when>
    	              <when test="lastName!=null">
    	                  last_name = #{lastName}
    	              </when>
    	              <when test="email!=null">
    	                  email = #{email}
    	              </when>
                      <otherwise>
                          gender = 0
                      </otherwise>
    	          </choose>
    	      </where>
    	</select>

TestMyBatisDynamicSQL.java

@Test
    	public void testChoose() 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("0");
    			
    			List<Employee> emps = mapper.selectEmployeeByConditionChoose(condition);
    			System.out.println(emps);
    			
    			session.commit();
    		} finally { 
    			// TODO: handle finally clause
    			session.close();
    		}
    		
    	}