mapper分页排序指定字段查询模板

StudentQuery:

package Student;

import java.util.ArrayList;
import java.util.List;

public class StudentQuery {
    private Integer id;
    private String no;
    private String name;
    private String age;
    private float score;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getNo() {
        return no;
    }
    public void setNo(String no) {
        this.no = no;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAge() {
        return age;
    }
    public void setAge(String age) {
        this.age = age;
    }
    public float getScore() {
        return score;
    }
    @Override
    public String toString() {
        return "StudentQuery [id=" + id + ", no=" + no + ", name=" + name
                + ", age=" + age + ", score=" + score + ", fields=" + fields
                + "]";
    }
    public void setScore(float score) {
        this.score = score;
    }
    
    private String fields;
    public String getFields() {
        return fields;
    }
    public void setFields(String fields) {
        this.fields = fields;
    }
    
    public class FieldOrder{
        private String field;  //id , name  imgUrl
        private String order;  // desc asc
        
        public FieldOrder(String field, String order) {
            super();
            this.field = field;
            this.order = order;
        }
        public String getField() {
            return field;
        }
        public void setField(String field) {
            this.field = field;
        }
        public String getOrder() {
            return order;
        }
        public void setOrder(String order) {
            this.order = order;
        }
    }
    
    //orderby 集合
    private List<FieldOrder> fieldOrders = new ArrayList<FieldOrder>();
        
    //按照Id排序
    public void orderbyId(boolean isAsc){
        fieldOrders.add(new FieldOrder("id",isAsc == true ? "asc" : "desc"));
    }
    
    private Integer pageNo = 1;
    private Integer startRow;
    private Integer pageSize = 10;
    public Integer getPageNo() {
        return pageNo;
    }
    public void setPageNo(Integer pageNo) {
        this.startRow = (pageNo - 1) * pageSize;
        this.pageNo = pageNo;
    }
    public Integer getStartRow() {
        return startRow;
    }
    public void setStartRow(Integer startRow) {
        this.startRow = startRow;
    }
    public Integer getPageSize() {
        return pageSize;
    }
    public void setPageSize(Integer pageSize) {
        this.startRow = (pageNo - 1) * pageSize;
        this.pageSize = pageSize;
    }
}

mapper语句

  <sql id="studentSelector">
      select
      <if test="fields != null">
          ${fields}
      </if>
      <if test="fields == null">
          id, no, name, age, score
      </if>
          from student
  </sql>
  
  <sql id="studentOrderBy">
      <if test="fieldOrders != null and fieldOrders.size > 0">
          order by
          <foreach collection="fieldOrders" item="fieldOrder" separator=",">
              ${fieldOrder.field} ${fieldOrder.order}  
          </foreach>
      </if>
  </sql>
  
  <sql id="studentLimit">
      <if test="startRow != null">
          limit ${startRow}, ${pageSize}
      </if>
  </sql>
  
  <select id="getStudentList" parameterType="StudentQuery" resultMap="BaseResultMap">
      <include refid="studentSelector"></include>
      <include refid="studentOrderBy"></include>
      <include refid="studentLimit"></include>
  </select>

test

public class Test {
    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-dao.xml");
        StudentMapper studentMapper = (StudentMapper) ctx.getBean("studentMapper");
        StudentQuery studentQuery = new StudentQuery();
        studentQuery.setFields("id, name");
        studentQuery.orderbyId(false);
        studentQuery.setPageNo(2);
        studentQuery.setPageSize(2);
        List<Student> students = studentMapper.getStudentList(studentQuery);
        for(Student s : students){
            System.out.println(s);
        }
    }
}