3.19作业

 

test.java

package com.student.pojo;

import com.student.util.MybatisUtils;
import org.apache.ibatis.session.SqlSession;

import java.util.List;
import java.util.Scanner;

public class Test {
    @org.junit.Test
    public void stuSystem(){
        System.out.println("1.多条件查询");
        System.out.println("2.单条件查询");
        System.out.println("3.学生信息更新");
        System.out.print("请输入：");
        Scanner scanner = new Scanner(System.in);
        switch (scanner.nextInt()){
            case 1:
                findArray();
                break;
            case 2:
                findByAge();
                break;
            case 3:
                update();
                break;
        }
    }

    private void update() {
        SqlSession session = MybatisUtils.getSession();
        Scanner scanner = new Scanner(System.in);
        Student student = new Student();
        System.out.println("输入更新id：");
        student.setId(scanner.nextInt());
        System.out.println("输入更新姓名：");
        student.setName(scanner.next());
        System.out.println("输入更新专业：");
        student.setMajor(scanner.next());
        System.out.println("输入更新年龄：");
        student.setAge(scanner.nextInt());
        System.out.println("输入更新性别：");
        student.setSex(scanner.next());
        session.update("edit",student);
        session.commit();
    }

    private static void findArray() {
        SqlSession session = MybatisUtils.getSession();
        Student student = inputSelect();
        List<Student> students = session.selectList("findArray",student);
        for (Student s:students) {
            System.out.println(s);
        }
    }
    public static Student inputSelect(){
        Scanner scanner = new Scanner(System.in);
        Student student = new Student();
        int a;
        do {
            System.out.println("1.依据ID查询信息");
            System.out.println("2.依据姓名查询信息");
            System.out.println("3.依据专业查询信息");
            System.out.println("4.依据年龄查询信息");
            System.out.println("5.依据性别查询信息");
            System.out.println("6.保存并结束");
            System.out.print("请选择操作：");
            a = scanner.nextInt();
            switch (a){
                case 1:
                    System.out.print("请输入ID：");
                    student.setId(scanner.nextInt());
                    break;
                case 2:
                    System.out.print("请输入姓名：");
                    student.setName(scanner.next());
                    break;
                case 3:
                    System.out.print("请输入专业：");
                    student.setMajor(scanner.next());
                    break;
                case 4:
                    System.out.print("请输入年龄：");
                    student.setAge(scanner.nextInt());
                    break;
                case 5:
                    System.out.print("请输入性别：");
                    student.setSex(scanner.next());
                    break;
            }
        } while (a!=6);
        return student;
    }
    private void findByAge() {
        SqlSession session = MybatisUtils.getSession();
        System.out.println("查询小于年龄18岁的学生信息");
        List<Student> students = session.selectList("findByAge",18);
        for (Student s:students) {
            System.out.println("年龄小于18岁的学生信息:"+s);
        }
    }
}

StudentMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.student.pojo.Student">
    <!-- 多条件查询 -->
    <select id="findArray" parameterType="com.student.pojo.Student" resultType="com.student.pojo.Student">
        SELECT * from student
        <trim prefix="where" prefixOverrides="and">
            <choose>
                <when test="id != null and id != ''">
                    and id = #{id}
                </when>
                <when test="name != null and name != ''">
                    and name=#{name}
                </when>
                <when test="major != null and major != ''">
                    and major = #{major}
                </when>
                <when test="age != null and age != ''">
                    and age = #{age}
                </when>
                <when test="sex != null and sex != ''">
                    and sex = #{sex}
                </when>
            </choose>
        </trim>
    </select>
    <select id="findByAge" parameterType="Integer" resultType="com.student.pojo.Student">
        SELECT * from student where age &lt; #{id};
    </select>
    <update id="edit" parameterType="com.student.pojo.Student">
    <!--        传参的方法类型为主类的路径-->
    update student
    <trim prefix="set" suffixOverrides=",">
        <!--            prefix为原<set></set> suffixOverrides要去除每条if中的语句的逗号-->
        <if test="name != null and name != ''">
            <!--                test中的name job phone与Customer中private的name job phone相同-->
            <!--                条件与查询一样 解释：为当name不为空 同时 也不为空串-->
            name = #{name},
        </if>
        <if test="major != null and major != ''">
            major = #{major},
        </if>
        <if test="age !=null and age != ''">
            age = #{age},
        </if>
        <if test="sex !=null and sex != ''">
            sex = #{sex}
        </if>
    </trim>
    where id =#{id}
    </update>
</mapper>