MyBatis入門：

第一天接觸Mybatis，總結(jié)一下入門案例的流程:

首先導(dǎo)入Mybatis的jar包和數(shù)據(jù)庫的驅(qū)動(dòng)包

1.創(chuàng)建數(shù)據(jù)表和實(shí)體類

2.創(chuàng)建一個(gè)表和實(shí)體類映射的xml配置文件，具體配置如下：

1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE mapper 3 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 5 <!-- namespace是映射文件的一個(gè)唯一標(biāo)識(shí)，用來定位是哪個(gè)映射文件 --> 6 <mapper namespace="com.offcn.entity.personMapper"> 7 <!-- id是一條sql語句的唯一標(biāo)識(shí),parameterType是sql語句中的參數(shù)類型 ，resultType是sql語句將要返回的結(jié)果的類型 --> 8 <!-- 如果輸入的類型是基本數(shù)據(jù)類型（八種基本數(shù)據(jù)類型 + string）則#{xxx}可以隨意寫，但是為了規(guī)范最好不要，如果不是基本數(shù)據(jù)類型則必須寫實(shí)體類中的字段名 --> 9 <select id="selectPersonById" parameterType="int" resultType="com.offcn.entity.Person"> 10 select * from Person where id = #{id} 11 </select> 12 <!-- sql語句后邊不加分號(hào) --> 13 14 <insert id="insertPerson" parameterType="com.offcn.entity.Person"> 15 insert into Person (id,name,bir,address) value (#{id},#{name},#{bir},#{address}) 16 </insert> 17 18 <delete id="deletePersonById" parameterType="int"> 19 delete from Person where id = #{id} 20 </delete> 21 22 <update id="updatePerson" parameterType="com.offcn.entity.Person"> 23 update person set name=#{name},bir=#{bir},address=#{address} where id = #{id} 24 </update> 25 26 <select id="selectPerson" resultType="com.offcn.entity.Person"> 27 select * from person 28 </select> 29 30 </mapper>

3.編寫全局配置文件conf.xml,包含數(shù)據(jù)庫信息和映射文件信息,代碼如下:

1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE configuration 3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 5 <configuration> 6 <!-- 環(huán)境的配置,可以配置多個(gè),可以通過default該換id定位使用哪個(gè)環(huán)境,也可以通過 sessionFactory的第二個(gè)參數(shù)設(shè)置--> 7 <environments default="development"> 8 <environment id="development"> 9 <!-- 配置事物的提交方式,一共有兩種 10 1.JDBC:利用JDBC的方式處理事務(wù)，需要手動(dòng)提交(commit,rollback,close) 11 2.MANAGED：將事務(wù)由其他組件托管（spring,jobss）,默認(rèn)會(huì)關(guān)閉連接，如果想要自動(dòng)關(guān)閉連接需要配置一個(gè)屬性 12 <property name="driver" value="false"/> 13 --> 14 <transactionManager type="JDBC"/> <!-- 后邊的斜杠不能省略 --> 15 16 <!-- 數(shù)據(jù)源格式類型: 17 1.POOLED:數(shù)據(jù)連接池模式 18 2.UNPOOLED:傳統(tǒng)的jdbc模式，每次都需要自己手動(dòng)創(chuàng)建關(guān)閉 19 3.JNDI:從tomcat中獲取一個(gè)內(nèi)置的數(shù)據(jù)庫連接池 20 --> 21 <dataSource type="POOLED"> 22 <property name="driver" value="com.mysql.jdbc.Driver"/> 23 <property name="url" value="jdbc:mysql://localhost:3306/person?serviceTimeout=UTC"/> 24 <property name="username" value="root"/> 25 <property name="password" value="root"/> 26 </dataSource> 27 </environment> 28 </environments> 29 <mappers> 30 <mapper resource="com/offcn/entity/personMapper.xml"/> 31 </mappers> 32 </configuration>

3.寫一個(gè)測(cè)試類，進(jìn)行增刪改查的測(cè)試,步驟如下：

1 package com.offcn.entity; 2 3 import java.io.IOException; 4 import java.io.Reader; 5 import java.util.Date; 6 import java.util.List; 7 8 import org.apache.ibatis.io.Resources; 9 import org.apache.ibatis.session.SqlSession; 10 import org.apache.ibatis.session.SqlSessionFactory; 11 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 12 13 public class Test { 14 public static void main(String[] args) throws IOException { 15 // selectPerosnById(); 16 //insertPerson(); 17 //deletePersonById(); 18 //updatePerson(); 19 selectPerson(); 20 } 21 //根據(jù)id查詢 22 public static void selectPerosnById() throws IOException { 23 //讀取conf.xml 配置文件 24 Reader reader = Resources.getResourceAsReader("conf.xml"); 25 //創(chuàng)建sqlSessionFactory 26 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader); 27 //創(chuàng)建session---> connection 28 SqlSession session = sessionFactory.openSession(); 29 //statement ---> statement 30 String sql = "com.offcn.entity.personMapper." + "selectPersonById"; 31 //查詢一條數(shù)據(jù) 32 Person person = session.selectOne(sql,1); 33 //提交事務(wù) 34 session.commit(); 35 System.out.println(person); 36 //關(guān)閉連接 37 session.close(); 38 39 } 40 //增加一條數(shù)據(jù) 41 public static void insertPerson() throws IOException { 42 //讀取conf.xml文件 43 Reader reader = Resources.getResourceAsReader("conf.xml"); 44 //創(chuàng)建一個(gè)sqlSessionFactory 45 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader); 46 //創(chuàng)建一個(gè)session對(duì)象 47 SqlSession session = sessionFactory.openSession(); 48 //定位sql語句 49 String statement = "com.offcn.entity.personMapper." + "insertPerson"; 50 //執(zhí)行sql語句 51 Person person = new Person("李四",new Date(),"上海普陀"); 52 int count = session.insert(statement,person); 53 //提交事務(wù) 54 session.commit(); 55 System.out.println("增加"+count+"條數(shù)據(jù)"); 56 //關(guān)閉連接 57 session.close(); 58 } 59 //根據(jù)id刪除一條數(shù)據(jù) 60 public static void deletePersonById() throws IOException { 61 //讀取conf.xml文件 62 Reader reader = Resources.getResourceAsReader("conf.xml"); 63 //獲取sqlSessionFactory 64 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader); 65 //獲取session對(duì)象 66 SqlSession session = sessionFactory.openSession(); 67 //定位sql語句 68 String statement = "com.offcn.entity.personMapper."+"deletePersonById"; 69 //執(zhí)行sql語句 70 int count = session.delete(statement,2); 71 //提交事務(wù) 72 session.commit(); 73 System.out.println("刪除"+count+"條數(shù)據(jù)"); 74 //關(guān)閉連接 75 session.close(); 76 } 77 //更改數(shù)據(jù) 78 public static void updatePerson() throws IOException { 79 //讀取conf.xml 80 Reader reader = Resources.getResourceAsReader("conf.xml"); 81 //創(chuàng)建sqlSessionFactory 82 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader); 83 //創(chuàng)建sqlsession對(duì)象 84 SqlSession session = sessionFactory.openSession(); 85 //定位sql 86 String statement = "com.offcn.entity.personMapper." + "updatePerson"; 87 //執(zhí)行sql語句 88 Person person = new Person(); 89 person.setName("王五"); 90 person.setBir(new Date()); 91 person.setAddress("南京"); 92 person.setId(1); 93 int count = session.update(statement,person); 94 //提交事務(wù) 95 session.commit(); 96 System.out.println("更改" + count +"條數(shù)據(jù)成功"); 97 //關(guān)閉連接 98 session.close(); 99 } 100 //查詢所有數(shù)據(jù) 101 public static void selectPerson() throws IOException { 102 //讀取conf.xml 103 Reader reader = Resources.getResourceAsReader("conf.xml"); 104 //創(chuàng)建sqlSessionFactory 105 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader); 106 //創(chuàng)建sqlsession對(duì)象 107 SqlSession session = sessionFactory.openSession(); 108 //定位sql 109 String statement = "com.offcn.entity.personMapper." + "selectPerson"; 110 //執(zhí)行sql語句 111 List<Person> persons = session.selectList(statement); 112 //提交事務(wù) 113 session.commit(); 114 for (Person person : persons) { 115 System.out.println(person); 116 } 117 118 //關(guān)閉連接 119 session.close(); 120 } 121 }

到此就完成了一個(gè)Mybatis的入門程序。

轉(zhuǎn)載于:https://www.cnblogs.com/man-tou/p/11332626.html

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