若依框架 ------- 三级联动之下拉框查询

太过爱你忘了你带给我的痛 2023-09-24 16:36 25阅读 0赞

### 联动 ###

因为是查询要放在查询的位置

![b89dae490d404f2daa12679a1c0a298e.png][]

![7e933b32bf8548b8bb3c10b171777863.png][]

**HTML页面（显示）**

<li>
    	学生学校：
    
    	<select id="school" name="sysGrade.gradeSchool">
    		<option value="">请选择学校</option>
    	</select>
    	学生年级：
    
    	<select id="grade" name="sysClasses.classesGrade">
    		<option value="">请选择年级</option>
    	</select>
    	学生年级：
    
    	<select id="classes" name="studentClass">
    		<option value="">请选择班级</option>
    	</select>
    </li>

**js方法（都是重复的，区别：第一个是查全部，之后都是传参查的）**

**controler层**  
**school**

@GetMapping("/select")
        @ResponseBody
        public List<SysSchool> select()
        {
            List<SysSchool> list = schoolService.selectSchoolList(new SysSchool());
            return  list;
        }

**grade**

@GetMapping("/select")
        @ResponseBody
        public List<SysGrade> select(Long gradeSchool)
        {
    //        System.out.println("11111111111111111111");
    //        System.out.println(gradeSchool);
            List<SysGrade> list1 = gradeService.selectGradeById1(gradeSchool);
            List<SysGrade> list = gradeService.selectGradeList(new SysGrade());
            return  list1;
        }

**classes**

@GetMapping("/select")
        @ResponseBody
        public List<SysClasses> select(Long classesGrade)
        {
            List<SysClasses> list1 = classesService.selectClassesById1(classesGrade);
            List<SysClasses> list = classesService.selectClassesList(new SysClasses());
            return  list1;
        }

**mapper.xml(写sql语句的地方)**  
方法都一样，这里就不都写了，只写一个grade表的

<select id="selectClassesById1" parameterType="Long" resultMap="SysClassesResult">
    		<include refid="selectClassesVo"/>
    		where classes_grade = #{classesGrade}
    	</select>

**mapper.java**

public List<SysGrade> selectGradeById1(Long gradeSchool);

**service层**

public List<SysGrade> selectGradeById1(Long gradeSchool);

**serviceImpl层**

@Override
        public List<SysGrade> selectGradeById1(Long gradeSchool)
        {
            return gradeMapper.selectGradeById1(gradeSchool);
        }

### 下拉框查询的传值 ###

![0e05703ed2e241b09b5f68a767b29249.png][]

要先进行表连接，建立关系，不然怎么查，  
**表连接的**  
几个字段，还有SQL语句  
![e58f51942fec40abb7ae1510b14da412.png][]

<sql id="selectStudentVo">
            SELECT * FROM sys_student
    			INNER JOIN sys_classes
    			INNER JOIN sys_grade
    			INNER JOIN sys_school
    				ON sys_student.`student_class` = sys_classes.`classes_id`
    				AND sys_classes.`classes_grade` = sys_grade.`grade_id`
    				AND sys_grade.`grade_school` = sys_school.`school_id`
        </sql>

**下拉框查询的**  
注意，这里需要改一下id的格式，不然查不了，是一个本人解决不了，或者本身就存在的问题，改字段类型，char，varchar都可以。后期解决会发布，也求大神改正。

![c41940aa8cf24bcc9f93728545e61291.png][]

![90e4fdeae3e74cbebe480159fbfdf911.png][]

<select id="selectStudentList" parameterType="SysStudent" resultMap="SysStudentResult">
    		<include refid="selectStudentVo"/>
    		<where>
    			<if test="studentName != null and studentName != ''">
    				AND student_name like concat('%', #{studentName}, '%')
    			</if>
    			<if test="abs != null and abs != ''">
    				AND abs like concat('%', #{abs}, '%')
    			</if>
    			<if test="sysGrade.gradeSchool != null and sysGrade.gradeSchool != ''">
    				AND sys_grade.grade_school =#{sysGrade.gradeSchool}
    			</if>
    			<if test="sysClasses.classesGrade != null and sysClasses.classesGrade != ''">
    				AND sys_classes.classes_grade =#{sysClasses.classesGrade}
    			</if>
    			<if test="studentClass != null and studentClass != ''">
    				AND student_class =#{studentClass}
    			</if>
    		</where>
    		ORDER BY sys_student.`abs` DESC
    		,sys_student.`student_id` ASC
    	</select>

[b89dae490d404f2daa12679a1c0a298e.png]: https://img-blog.csdnimg.cn/b89dae490d404f2daa12679a1c0a298e.png
[7e933b32bf8548b8bb3c10b171777863.png]: https://img-blog.csdnimg.cn/7e933b32bf8548b8bb3c10b171777863.png
[0e05703ed2e241b09b5f68a767b29249.png]: https://img-blog.csdnimg.cn/0e05703ed2e241b09b5f68a767b29249.png
[e58f51942fec40abb7ae1510b14da412.png]: https://img-blog.csdnimg.cn/e58f51942fec40abb7ae1510b14da412.png
[c41940aa8cf24bcc9f93728545e61291.png]: https://img-blog.csdnimg.cn/c41940aa8cf24bcc9f93728545e61291.png
[90e4fdeae3e74cbebe480159fbfdf911.png]: https://img-blog.csdnimg.cn/90e4fdeae3e74cbebe480159fbfdf911.png