Java进阶知识32 mybatis（ibatis）入门CRUD操作【简单演示，只测DAO层】
本文知识点（目录）：
1、导读
1.1、技术概述
1.2、本文使用的jar包、项目结构图
2、本文所有代码
2.1、数据库脚本（oracle.sql）
2.2、mybatis.xml 核心配置文件
2.3、MyBatisUtils 工具类（用于连接数据库）
2.4、Student 实体类
2.5、Student 实体类的配置文件（StudentMapper.xml）
2.6、DAO层 （StudentDao）
2.7、测试类（StudentDaoTest）
1、导读
a.本文使用的是Oracle+mybatis框架，只是演示/测试DAO层（连接数据库，进行数据测试）；
b.实现了CURD等操作：新增、修改、查询所有、根据id查询、删除、批量删除
c.本项目的使用环境：MyEclipse10.7 + JDK1.8 + Oracle11g + mybatis3.1.1
2、本文所有代码
1 -- 创建表 2 create table student( 3 id number(6) primary key, 4 name varchar2(20), 5 sex number(1), 6 age number(3), 7 telphone varchar2(16) 8 ); 9 10 -- 创建序列 11 create sequence student_seq 12 minvalue 1 --最小值 13 maxvalue 99999 -- 最大值 14 increment by 1 --从1开始计数 15 start with 1 --每次加1 16 nocycle --一直累加，不循环 17 nocache; --不建缓冲区。 18 19 create or replace trigger student_tg 20 before insert on student for each row 21 begin 22 select student_seq.Nextval into:new.id from dual; 23 end; 24 25 -- 插入数据 26 insert into student(name,sex,age,telphone) values('zhangsan',1,23,'18795901366');
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 4 <configuration> 5 <environments default="development"> 6 <environment id="development"> 7 <transactionManager type="JDBC" /> 8 <dataSource type="POOLED"> 9 <property name="driver" value="oracle.jdbc.driver.OracleDriver" /> 10 <property name="url" value="jdbc:oracle:thin:@localhost:1521:shoreid" /> 11 <property name="username" value="zhangsan" /> 12 <property name="password" value="123456" /> 13 </dataSource> 14 </environment> 15 </environments> 16 17 <mappers> 18 <mapper resource="com/shore/entity/StudentMapper.xml"/> 19 </mappers> 20 </configuration>
1 package com.shore.utils; 2 3 import java.io.Reader; 4 5 import org.apache.ibatis.io.Resources; 6 import org.apache.ibatis.session.SqlSession; 7 import org.apache.ibatis.session.SqlSessionFactory; 8 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 9 10 /** 11 * @author DSHORE/2020-3-11 12 * 13 */ 14 public class MyBatisUtils { 15 private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>(); 16 private static SqlSessionFactory sqlSessionFactory; 17 18 static{ 19 try { 20 //1、读取配置 21 Reader reader = Resources.getResourceAsReader("mybatis.xml"); 22 //2、创建SqlSessionFactory 23 sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); 24 } catch (Exception e) { 25 e.fillInStackTrace(); 26 throw new RuntimeException(e); 27 } 28 } 29 30 private MyBatisUtils() { } 31 32 //获取SqlSession 33 public static SqlSession getSqlSession(){ 34 SqlSession sqlSession = threadLocal.get(); 35 if (sqlSession == null) {//如果上面获取不到SQLSession，将通过下面的方式来获取 36 sqlSession = sqlSessionFactory.openSession(); 37 } 38 return sqlSession; 39 } 40 41 //关闭SqlSession 42 public static void closeSqlSession() { 43 SqlSession sqlSession = threadLocal.get(); 44 if (sqlSession != null) { 45 sqlSession.close(); 46 threadLocal.remove(); 47 } 48 } 49 }
1 package com.shore.entity; 2 3 /** 4 * @author DSHORE/2020-3-11 5 * 6 */ 7 public class Student { 8 private Integer id; 9 private String name; 10 private Integer sex; 11 private Integer age; 12 private String telphone; 13 14 public Integer getId() { 15 return id; 16 } 17 18 public void setId(Integer id) { 19 this.id = id; 20 } 21 22 public String getName() { 23 return name; 24 } 25 26 public void setName(String name) { 27 this.name = name; 28 } 29 30 public Integer getSex() { 31 return sex; 32 } 33 34 public void setSex(Integer sex) { 35 this.sex = sex; 36 } 37 38 public Integer getAge() { 39 return age; 40 } 41 42 public void setAge(Integer age) { 43 this.age = age; 44 } 45 46 public String getTelphone() { 47 return telphone; 48 } 49 50 public void setTelphone(String telphone) { 51 this.telphone = telphone; 52 } 53 54 @Override 55 public String toString() { 56 return "Student [id=" + id + ", name=" + name + ", sex=" + sex 57 + ", age=" + age + ", telphone=" + telphone + "]"; 58 } 59 }
2.5、Student 实体类的配置文件（StudentMapper.xml）
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 4 5 <mapper namespace="student"> 6 <!--=======================查询============================= --> 7 <!-- 1、查询所有 --> 8 <select id="selectAll" resultType="com.shore.entity.Student"> 9 select * from student 10 </select> 11 12 <!-- 2、根据id查询 --> 13 <select id="findById" parameterType="int" resultType="com.shore.entity.Student"> 14 select * from student where id=#{id} 15 </select> 16 17 <!-- 3、动态条件查询 --> 18 <select id="dynamicSelect" parameterType="map" resultType="com.shore.entity.Student"> 19 select * from student 20 <where> 21 <if test="name != null"> 22 and name = #{name} 23 </if> 24 <if test="telphone != null"> 25 and telphone = #{telphone} 26 </if> 27 </where> 28 </select> 29 30 <!--=======================4、新增============================= --> 31 <insert id="dynamicInsert" parameterType="com.shore.entity.Student"> 32 insert into student(name,sex,age,telphone) 33 values(#{name},#{sex},#{age},#{telphone}) 34 </insert> 35 36 <!--=======================5、更新============================= --> 37 <update id="dynamicUpdate" parameterType="com.shore.entity.Student"> 38 update student 39 set name=#{name}, 40 sex=#{sex}, 41 age=#{age}, 42 telphone=#{telphone} 43 where id=#{id} 44 </update> 45 46 <!--=======================6、删除============================= --> 47 <delete id="deleteById" parameterType="int"> 48 delete from student where id=#{id} 49 </delete> 50 51 <!--=======================7、批量删除============================= --> 52 <delete id="batchDeleteById"> 53 delete from student where id in 54 <foreach item="ids" collection="list" open="(" separator="," close=")"> 55 #{ids} 56 </foreach> 57 </delete> 58 </mapper>
为了方便，此处不写接口，我直接写实现类
1 package com.shore.dao; 2 3 import java.util.ArrayList; 4 import java.util.HashMap; 5 import java.util.List; 6 import java.util.Map; 7 8 import org.apache.ibatis.session.SqlSession; 9 10 import com.shore.entity.Student; 11 import com.shore.utils.MyBatisUtils; 12 13 /** 14 * @author DSHORE/2020-3-11 15 * 16 */ 17 public class StudentDao { 18 // 1、查询全部 19 public List<Student> listAll() { 20 List<Student> bosses = new ArrayList<Student>(); 21 SqlSession sqlSession = MyBatisUtils.getSqlSession(); 22 try { 23 bosses = sqlSession.selectList("student.selectAll"); 24 } catch (Exception e) { 25 // sqlSession.rollback(); //事务回滚 26 System.out.println("error:" + e.getMessage());//获取异常信息，打印到控台 27 } finally { 28 // sqlSession.commit(); //查询操作不用提交、不用回滚 29 MyBatisUtils.closeSqlSession();//关闭SqlSession 30 } 31 return bosses; 32 } 33 34 // 2、根据id查询 35 public Student findById(int id) { 36 Student student = null; 37 SqlSession sqlSession = MyBatisUtils.getSqlSession(); 38 try { 39 List<Student> students = sqlSession.selectList("student.findById", id); 40 if (students != null && students.size() > 0) { 41 student = students.get(0); 42 } 43 } catch (Exception e) { 44 System.out.println("error:" + e.getMessage());//获取异常信息，打印到控台 45 } finally { 46 MyBatisUtils.closeSqlSession();//关闭SqlSession 47 } 48 return student; 49 } 50 51 // 3、动态条件查询 52 public List<Student> dynamicSelect(String name, String telphone) { 53 List<Student> students = new ArrayList<Student>(); 54 SqlSession sqlSession = MyBatisUtils.getSqlSession(); 55 try { 56 Map<String, String> map = new HashMap<String, String>(); 57 map.put("name", name); 58 map.put("telphone", telphone); 59 students = sqlSession.selectList("student.dynamicSelect", map); 60 } catch (Exception e) { 61 System.out.println("error:" + e.getMessage()); 62 } finally { 63 MyBatisUtils.closeSqlSession(); 64 } 65 return students; 66 } 67 68 // 4、动态插入 69 public int dynamicInsert(Student student) { 70 SqlSession sqlSession = MyBatisUtils.getSqlSession(); 71 try { 72 return sqlSession.insert("student.dynamicInsert", student); 73 } catch (Exception e) { 74 sqlSession.rollback();//如果出现异常，则事务回滚 75 } finally { 76 sqlSession.commit();//提交事务 77 MyBatisUtils.closeSqlSession();//关闭SqlSession 78 } 79 return 0; 80 } 81 82 // 5、动态更新 83 public int dynamicUpdate(Student student) { 84 SqlSession sqlSession = MyBatisUtils.getSqlSession(); 85 try { 86 return sqlSession.update("student.dynamicUpdate", student); 87 } catch (Exception e) { 88 sqlSession.rollback(); 89 } finally { 90 sqlSession.commit(); 91 MyBatisUtils.closeSqlSession(); 92 } 93 return 0; 94 } 95 96 // 6、删除(根据id删除) 97 public int deleteByInt(int id) { 98 SqlSession sqlSession = MyBatisUtils.getSqlSession(); 99 try { 100 return sqlSession.delete("student.deleteById", id); 101 } catch (Exception e) { 102 sqlSession.rollback(); 103 } finally { 104 sqlSession.commit(); 105 MyBatisUtils.closeSqlSession(); 106 } 107 return 0; 108 } 109 110 // 7、批量删除 111 public int batchDeleteById(List<Integer> ids) { 112 SqlSession sqlSession = MyBatisUtils.getSqlSession(); 113 try { 114 return sqlSession.delete("student.batchDeleteById", ids); 115 } catch (Exception e) { 116 sqlSession.rollback(); 117 System.out.println("error:"+e.getMessage()); 118 } finally { 119 sqlSession.commit(); 120 MyBatisUtils.closeSqlSession(); 121 } 122 return 0; 123 } 124 }
1 package com.shore.test; 2 3 import java.util.ArrayList; 4 import java.util.List; 5 6 import org.junit.Test; 7 8 import com.shore.dao.StudentDao; 9 import com.shore.entity.Student; 10 11 /** 12 * @author DSHORE/2020-3-11 13 * 14 */ 15 public class StudentDaoTest { 16 StudentDao studentDao = new StudentDao(); 17 18 @Test // 1、查询全部 19 public void testListAll() { 20 List<Student> students = studentDao.listAll(); 21 if (students == null) { 22 System.out.println("students is null。"); 23 } else { 24 //返回值：Student [id=1, name=zhangsan, sex=0, age=26, telphone=12345678900] 25 System.out.println(students.get(0)); 26 } 27 } 28 29 @Test // 2、根据id查询 30 public void testFindById() { 31 Student student = studentDao.findById(1); 32 //返回值：Student [id=1, name=zhangsan, sex=0, age=26, telphone=12345678900] 33 System.out.println(student); 34 } 35 36 @Test // 3、动态条件查询 37 public void testDynamicSelect() { 38 List<Student> students = studentDao.dynamicSelect(null, "18795901366"); 39 List<Student> students2 = studentDao.dynamicSelect("zhangsan","12345678900"); 40 System.out.println(students.size());//返回值：1 41 //返回值：Student [id=1, name=zhangsan, sex=0, age=26, telphone=12345678900] 42 System.out.println(students2.get(0)); 43 } 44 45 // 4、动态插入 46 @Test 47 public void testDynamicInsert() { 48 Student student = new Student(); 49 student.setName("王五"); 50 student.setSex(1);//0代表男，1代表女 51 student.setAge(26); 52 student.setTelphone("13859501266"); 53 System.out.println(studentDao.dynamicInsert(student));//返回值：1 说明插入数据成功 54 } 55 56 // 5、动态更新 57 @Test 58 public void testDynamicUpdate() { 59 Student student = new Student(); 60 student.setId(7); 61 student.setName("李四"); 62 student.setSex(0); 63 student.setAge(23); 64 student.setTelphone("18795901366"); 65 System.out.println(studentDao.dynamicUpdate(student));//返回值：1 说明更新数据成功 66 } 67 68 // 6、删除 69 @Test 70 public void testDelete() { 71 System.out.println(studentDao.deleteByInt(3));//返回值：1 说明删除数据成功 72 } 73 74 // 7、批量删除 75 @Test 76 public void testBatchDelete() { 77 List<Integer> ids = new ArrayList<Integer>(); 78 ids.add(4); 79 ids.add(5); 80 ids.add(6); 81 System.out.println(studentDao.batchDeleteById(ids));//返回值：3 说明批量删除数据成功 82 } 83 }
到此已完结！有任何问题，可留言。
mybatis单向一对一关联映射：https://www.cnblogs.com/dshore123/p/12489304.html
mybatis单向一对多关联映射：https://www.cnblogs.com/dshore123/p/12493450.html
mybatis单向多对多关联映射：https://www.cnblogs.com/dshore123/p/12526016.html
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原创作者：DSHORE 作者主页：http://www.cnblogs.com/dshore123/ 原文出自：https://www.cnblogs.com/dshore123/p/12463550.html 版权声明：欢迎转载，转载务必说明出处。（如果本文对您有帮助，可以点击一下右下角的 推荐，或评论，谢谢！） |
