JavaEE实验三：动态SQL
实验三：动态SQL
使用动态SQL进行条件查询、更新以及复杂查询操作。本实验要求利用本章所学知识完成一个学生信息系统，该系统要求实现3个以下功能:
1、多条件查询： 当用户输入的学生姓名不为空，则根据学生姓名进行学生信息的查询； 当用户输入的学生姓名为空，而学生专业不为空，则只根据学生专业进行学生的查询； 当用户输入的学生姓名不为空，且专业不为空，则根据姓名和专业查询学生信息。
当学生姓名和专业都为空，则查询所有学生信息
2、单条件查询：查询出所有id值小于5的学生的信息；
3、学生数据插入：插入三条学生的信息；
创建学生表(tb_student)并输入3条记录，表结构如下:
CREATE TABLE tb_student(
id int(32) PRIMARY KEY AUTO_INCREMENT,
name varchar(50),
major varchar(50),
varchar(16) );
实验步骤
- 1、创建maven项目，在pom.xml文件中配置依赖：MyBatis、mysql、Junit依赖
- 2、新建实体类Student
- 3、在resources下建db.properties、mybatis-config.xml文件。注意要在mybatis-config.xml文件中引入db.properties文件
- 4、在src.main.resources中建包com.mapper,包中建，StudentMapper接口
- 5、在mybatis-config.xml文件中注册StudentMapper.xml文件
- 6、在Test.java目录中创建测试类。
- 7、MybatisUtils
- 8、运行测试方法。
1、创建maven项目，在pom.xml文件中配置依赖：MyBatis、mysql、Junit依赖
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.example</groupId>
<artifactId>sy2</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.11</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml
**/ *.properties</include>
</includes>
<filtering>true</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.xml
**/ *.properties</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
</project>
2、新建实体类Student
package com.pojo;
public class Student {
private Integer id;
private String name;
private String major;
private String sno;
public Student() {
}
public Student(String name, String major, String sno) {
this.name = name;
this.major = major;
this.sno = sno;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getMajor() {
return major;
}
public void setMajor(String major) {
this.major = major;
}
public String getSno() {
return sno;
}
public void setSno(String sno) {
this.sno = sno;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", major='" + major + '\'' +
", sno='" + sno + '\'' +
'}';
}
}
3、在resources下建db.properties、mybatis-config.xml文件。注意要在mybatis-config.xml文件中引入db.properties文件
//db.properties
mysql.driver=com.mysql.cj.jdbc.Driver
mysql.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
mysql.username=root
mysql.password=123456
//mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<properties resource="db.properties"/>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${mysql.driver}"/>
<property name="url" value="${mysql.url}"/>
<property name="username" value="${mysql.username}"/>
<property name="password" value="${mysql.password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/StudentMapper.xml"/>
</mappers>
</configuration>
4、在src.main.resources中建包com.mapper,包中建，StudentMapper接口
package com.mapper;
import com.pojo.Student;
import java.util.List;
import java.util.Map;
public interface StudentMapper {
List<Student> findStudentByName(Student student);
List<Student> findStudentById(Integer[] array);
List<Student> findAllStudent(Student student);
int saveStudent(Map map);
List<Student> findStudentByNameOrMajor(Student student);
List<Student> findStudentByNameAndMajor(Student student);
}
5、在mybatis-config.xml文件中注册StudentMapper.xml文件
<?xml version="1.0" encoding="UTF8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- namespace指定Dao接口的完整类名,mybatis会依据这个接口动态创建一个实现类去实现这个接口，
而这个实现类是一个Mapper对象-->
<mapper namespace="com.mapper.StudentMapper">
<select id="findStudentByName" parameterType="student"
resultType="student">
select * from tb_student where 1=1
<if test="name!=null and name!=''">
and name like concat('%',#{name},'%')
</if>
</select>
<select id="findStudentByNameOrMajor" parameterType="student"
resultType="student">
select * from tb_student
<where>
<choose>
<when test="name !=null and name !=''">
and name like concat('%',#{name}, '%')
</when>
<when test="major !=null and major !=''">
and major= #{major}
</when>
</choose>
</where>
</select>
<select id="findStudentByNameAndMajor" parameterType="student"
resultType="student">
select * from tb_student
<where>
<if test="name!=null and name!=''">
and name like concat('%',#{name},'%')
</if>
<if test="major!=null and major!=''">
and major=#{major}
</if>
</where>
</select>
<select id="findAllStudent" parameterType="student"
resultType="student">
select * from tb_student
<where>
<choose>
<when test="name !=null and name !=''">
and name like concat('%',#{name}, '%')
</when>
<when test="major !=null and major !=''">
and major= #{major}
</when>
<otherwise>and id is not null</otherwise>
</choose>
</where>
</select>
<select id="findStudentById" parameterType="java.util.Arrays"
resultType="student">
select * from tb_student
<where>
<foreach item="id" index="index" collection="array"
open="id in(" separator="," close=")">#{id}
</foreach>
</where>
</select>
<insert id="saveStudent" parameterType="map" >
insert into tb_student(name,major,sno) values
<foreach collection="students" item="student" index="i" separator=",">
(#{student.name},#{student.major},#{student.sno})
</foreach>
</insert>
</mapper>
6、在Test.java目录中创建测试类。
import com.mapper.StudentMapper;
import com.pojo.Student;
import com.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class IfTest {
@Test
public void findStudentTest1() {
SqlSession session = MybatisUtils.getSqlsession();
StudentMapper mapper = session.getMapper(StudentMapper.class);
Student s1 = new Student();
s1.setName("朱其林");
List<Student> students = mapper.findStudentByName(s1);
for (Student s : students) {
System.out.println(s);
}
session.close();
}
@Test
public void findStudentTest2() {
SqlSession session = MybatisUtils.getSqlsession();
StudentMapper mapper = session.getMapper(StudentMapper.class);
Student s2 = new Student();
s2.setMajor("软件工程");
List<Student> students = mapper.findStudentByNameOrMajor(s2);
for (Student s : students) {
System.out.println(s);
}
session.close();
}
@Test
public void findStudentsTest3() {
SqlSession session = MybatisUtils.getSqlsession();
StudentMapper mapper = session.getMapper(StudentMapper.class);
Student s3 = new Student();
s3.setName("朱其林");
s3.setMajor("计算机科学");
List<Student> students = mapper.findStudentByNameAndMajor(s3);
for (Student s : students) {
System.out.println(s);
}
session.close();
}
@Test
public void findStudentsTest4() {
SqlSession session = MybatisUtils.getSqlsession();
StudentMapper mapper = session.getMapper(StudentMapper.class);
Student s4 = new Student();
List<Student> students = mapper.findAllStudent(s4);
for (Student s : students) {
System.out.println(s);
}
session.close();
}
@Test
public void findStudentsTest5() {
SqlSession session = MybatisUtils.getSqlsession();
StudentMapper mapper = session.getMapper(StudentMapper.class);
Integer[] Ids = {1,2,3,4};
List<Student> students = mapper.findStudentById(Ids);
for (Student s : students) {
System.out.println(s);
}
session.close();
}
@Test
public void saveStudentTest() {
SqlSession session = MybatisUtils.getSqlsession();
StudentMapper mapper = session.getMapper(StudentMapper.class);
Map<String,Object> map=new HashMap<>();
Student s1=new Student("张三","体育","031");
Student s2=new Student("李四","机电","041");
Student s3=new Student("朱六","多媒体","051");
List<Student> students= new ArrayList<Student>();
students.add(s1);
students.add(s2);
students.add(s3);
map.put("students",students);
int n = mapper.saveStudent(map);
if (n > 0)
session.commit();
List<Student> cs = mapper.findStudentByNameAndMajor(new Student());
for (Student s : cs) {
System.out.println(s);
}
session.close();
}
}
7、MybatisUtils
package com.utils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try
{
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
catch(IOException e) {
e.printStackTrace();
}
}
public static SqlSession getSqlsession(){return sqlSessionFactory.openSession();}
}
8、运行测试方法。
1、多条件查询： 当用户输入的学生姓名不为空，则根据学生姓名进行学生信息的查询；
2、多条件查询： 当用户输入的学生姓名为空，而学生专业不为空，则只根据学生专业进行学生的查询；
3、多条件查询：当用户输入的学生姓名不为空，且专业不为空，则根据姓名和专业查询学生信息。
4、多条件查询：当学生姓名和专业都为空，则查询所有学生信息
5.单条件查询：查询出所有id值小于5的学生的信息；
6.学生数据插入：插入三条学生的信息；
