1. 匿名参数，顺序传递参数
mapper:
List<Employee> selectByGenderAndAge(Short gender,String age );
xml:
<select id="selectByGenderAndAge" resultMap="BaseResultMap" >
select * from employee where gender = #{0} and age = #{1}
</select>
2. 使用@Param注解
mapper:
List<Employee> selectByGenderAndAge( @Param("gender") Short gender,@Param("age") String age );
xml:
<select id="selectByGenderAndAge" resultMap="BaseResultMap" >
select * from employee where gender = #{gender} and age = #{age}
</select>
3. 使用map传递参数
mapper：
List<Employee> selectByMapParams(Map params);
xml:
<select id="selectByMapParams" resultMap="BaseResultMap" parameterType="map">
select * from employee where gender = #{gender} and age = #{age}
</select>
4. 如果参数是 pojo，即实体类
mapper:
List <Employee> selectByBeans(Employee employee);
xml:
参数的引用直接使用实体类的字段
<select id="selectByBeans" resultMap="BaseResultMap" parameterType="com.wg.demo.po.Employee">
select
*
from employee where gender = #{gender} and age = #{age}
</select>
5. 使用json传递数据
controller: 使用@RequestBody注解之后，前端发送的json数据不会被转化为对象
@ApiOperation(value = "多个参数查询_通过JSON传递多个参数")
@PostMapping("findByJSONObject")
public ResultMsg findByJSONObject(@RequestBody JSONObject params)
{
List result= employeeMapper.findByJSONObject(params); //
return ResultMsg.getMsg(result);
}
mapper:
List <Employee> findByJSONObject(JSONObject params);
xml:
<select id="findByJSONObject" resultMap="BaseResultMap" parameterType="com.alibaba.fastjson.JSONObject">
select
*
from employee where gender = #{gender} and age = #{age}
</select>
6.
传递集合类型参数List、Set、Array
controller：
@ApiOperation(value = "多个参数查询_通过List、Set、Array传递多个参数")
@PostMapping("findByList")
public ResultMsg findByList(@RequestBody List<String> list)
{
List result= employeeMapper.findByList (list);
return ResultMsg.getMsg(result);
}
mapper：
List <Employee> findByList(List list);
xml：
<select id="findByList" resultMap="BaseResultMap" >
SELECT * from employee where age in
<foreach collection="list" open="(" separator="," close=")" item="age">
#{age}
</foreach>
</select>
foreach元素的属性主要有 item，index，collection，open，separator，close。
item表示集合中每一个元素进行迭代时的别名，
index指定一个名字，用于表示在迭代过程中，每次迭代到的位置，
open表示该语句以什么开始，
separator表示在每次进行迭代之间以什么符号作为分隔符，
close表示以什么结束
在使用foreach的时候最关键的也是最容易出错的就是collection属性，该属性是必须指定的，但是在不同情况下，该属性的值是不一样的，主要有一下3种情况：
1.如果传入的是单参数且参数类型是一个List的时候，collection属性值为list
2.如果传入的是单参数且参数类型是一个array数组的时候，collection的属性值为array
3.如果传入的参数是多个的时候，我们就需要把它们封装成一个Map或者Object
7. 参数类型为对象+集合
pojo：
@Data
public class Department {
private Long id;
private String deptName;
private String descr;
private Date createTime;
List<Employee> employees;
}
controller
@ApiOperation(value = "多个参数查询_对象+集合参数")
@PostMapping("findByDepartment")
public ResultMsg findByDepartment(@RequestBody Department department)
{
List result= employeeMapper.findByDepartment(department);
return ResultMsg.getMsg(result);
}
mapper：
List <Employee> findByDepartment(@Param("department")Department department);
xml;
<select id="findByDepartment" resultMap="BaseResultMap" parameterType="com.wg.demo.po.Department">
SELECT * from employee where dept_id =#{department.id} and age in
<foreach collection="department.employees" open="(" separator="," close=")" item="employee">
#{employee.age}
</foreach>
</select>
请求参数： 查询部门Id=1，并且年龄 等于24和25的员工
{
"createTime": "2019-07-02T10:17:16.756Z",
"deptName": "string",
"descr": "string",
"employees": [
{
"age": "24",
},
{
"age": "25",
}
],
"id": 1
}
结果：
{
"data": [
{
"address": "北新街ndcpc",
"age": "24",
"createTime": 1562062434000,
"deptId": "1",
"gender": 1,
"id": "318397755696631808",
"name": "kls0bx19cy"
},
{
"address": "北新街lavi0",
"age": "25",
"createTime": 1562062436000,
"deptId": "1",
"gender": 1,
"id": "318397755801489408",
"name": "gj9q3ygikh"
}
],
"result": "SUCCESS",
"resultCode": 200,
"resultMsg": ""
}
TRANSLATE with