mybatis学习之普通增删改查
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mybatis下载地址：https://github.com/mybatis/mybatis-3/releases
选择你要下载的版本，这里我下载的3.4.2版
项目结构：
将mybatis中的所有jar包导入还要导入链接mysql数据库的jar包。
其中db.properties,mybatis-config.xml,log4j.properties是在src下。
在mysql中新建mybatis数据库，在数据库中新建表t_customer，表结构如下：
随后向其中随便插入几条数据。
Customer.java
1 package com.itheima.po; 2 3 public class Customer 4 private Integer id; 5 private String username; 6 private String jobs; 7 private String phone; 8 @Override 9 public String toString() 10 return "Customer [id=" + id + ", username=" + username + ", jobs=" + jobs + ", phone=" + phone + "]"; 11 12 13 public Integer getId() 14 return id; 15 16 public void setId(Integer id) 17 this.id = id; 18 19 public String getUsername() 20 return username; 21 22 public void setUsername(String username) 23 this.username = username; 24 25 public String getJobs() 26 return jobs; 27 28 public void setJobs(String jobs) 29 this.jobs = jobs; 30 31 public String getPhone() 32 return phone; 33 34 public void setPhone(String phone) 35 this.phone = phone; 36 37 38
MybatisUtils.java
1 package com.itheima.utils; 2 3 import java.io.IOException; 4 import java.io.InputStream; 5 import java.io.Reader; 6 7 import org.apache.ibatis.io.Resources; 8 import org.apache.ibatis.session.SqlSession; 9 import org.apache.ibatis.session.SqlSessionFactory; 10 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 11 12 public class MybatisUtils 13 private static SqlSessionFactory sqlSessionFactory=null; 14 15 //初始化sqlSessionFactory 16 static 17 try 18 Reader reader=Resources.getResourceAsReader("mybatis-config.xml"); 19 sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader); 20 catch (IOException e) 21 // TODO Auto-generated catch block 22 e.printStackTrace(); 23 24 25 26 27 public static SqlSession getSqlSession() 28 return sqlSessionFactory.openSession(); 29 30 31
MybatisTest.java
1 package com.itheima.test; 2 3 import java.io.IOException; 4 import java.io.InputStream; 5 import java.util.List; 6 7 import org.apache.ibatis.io.Resources; 8 import org.apache.ibatis.session.SqlSession; 9 import org.apache.ibatis.session.SqlSessionFactory; 10 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 11 import org.junit.Test; 12 13 import com.itheima.po.Customer; 14 import com.itheima.po.User; 15 import com.itheima.utils.MybatisUtils; 16 17 //mybatis入门程序测试 18 19 public class MybatisTest 20 21 22 @Test 23 public void findCustomerById() throws IOException 24 // //1.读取配置文件 25 // String resourceString="mybatis-config.xml"; 26 // InputStream inputStream=Resources.getResourceAsStream(resourceString); 27 // //根据配置文件构建SqlSessionFactory 28 // SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream); 29 // //通过SqlSessionFactory创建sqlsession 30 // SqlSession sqlSession=sessionFactory.openSession(); 31 // //sqlSession执行映射文件中的sql语句，并返回结果 32 // //第一个参数为mapper.xml中的id，第二个是传入的占位符就是#id的值 33 SqlSession sqlSession=MybatisUtils.getSqlSession(); 34 35 36 Customer customer=sqlSession.selectOne("com.itheima.po.Customer.findCustomerById", 1); 37 System.out.println(customer.toString()); 38 //关闭sqlsession 39 sqlSession.close(); 40 41 @Test 42 public void findCustomerByName() throws IOException 43 //1.读取配置文件 44 String resource="mybatis-config.xml"; 45 InputStream inputStream=Resources.getResourceAsStream(resource); 46 //根据配置文件构建SqlSessionFactory 47 SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream); 48 //通过SqlSessionFactory创建sqlsession 49 SqlSession sqlSession=sessionFactory.openSession(); 50 List<Customer> customers= sqlSession.selectList("com.itheima.po.Customer.findCustomerByName","j"); 51 for (Customer customer:customers) 52 System.out.println(customer.toString()); 53 54 sqlSession.close(); 55 56 @Test 57 public void addCustomerTest() throws IOException 58 //1.读取配置文件 59 String resource="mybatis-config.xml"; 60 InputStream inputStream=Resources.getResourceAsStream(resource); 61 //根据配置文件构建SqlSessionFactory 62 SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream); 63 //通过SqlSessionFactory创建sqlsession 64 SqlSession sqlSession=sessionFactory.openSession(); 65 Customer customer=new Customer(); 66 customer.setUsername("zyk"); 67 customer.setJobs("hero"); 68 customer.setPhone("15035766618"); 69 int row=sqlSession.insert("com.itheima.po.Customer.addCustomer", customer); 70 if(row>0) 71 System.out.println("插入了"+row+"数据"); 72 else 73 System.out.println("插入失败"); 74 75 //注意要提交事务，增删改都涉及到事务 76 sqlSession.commit(); 77 sqlSession.close(); 78 79 @Test 80 public void updateCustomerTest() throws IOException 81 //1.读取配置文件 82 String resource="mybatis-config.xml"; 83 InputStream inputStream=Resources.getResourceAsStream(resource); 84 //根据配置文件构建SqlSessionFactory 85 SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream); 86 //通过SqlSessionFactory创建sqlsession 87 SqlSession sqlSession=sessionFactory.openSession(); 88 Customer customer=new Customer(); 89 customer.setId(7); 90 customer.setUsername("zyk1"); 91 customer.setJobs("student"); 92 customer.setPhone("15614141855"); 93 int row=sqlSession.update("com.itheima.po.Customer.updateCustomer", customer); 94 if(row>0) 95 System.out.println("修改成功"); 96 else 97 System.out.println("修改失败"); 98 99 //注意要提交事务，增删改都涉及到事务 100 sqlSession.commit(); 101 sqlSession.close(); 102 103 @Test 104 public void deleteCustomerTest() throws IOException 105 //1.读取配置文件 106 String resource="mybatis-config.xml"; 107 InputStream inputStream=Resources.getResourceAsStream(resource); 108 //根据配置文件构建SqlSessionFactory 109 SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream); 110 //通过SqlSessionFactory创建sqlsession 111 SqlSession sqlSession=sessionFactory.openSession(); 112 int row=sqlSession.delete("com.itheima.po.Customer.deleteCustomer", 3); 113 if(row>0) 114 System.out.println("删除成功"); 115 else 116 System.out.println("删除失败"); 117 118 //注意要提交事务，增删改都涉及到事务 119 sqlSession.commit(); 120 sqlSession.close(); 121 122 @Test 123 public void findAllUser() 124 SqlSession sqlSession=MybatisUtils.getSqlSession(); 125 List<User> users= sqlSession.selectList("com.itheima.po.User.findAllUser"); 126 for(User user:users) 127 System.out.println(user); 128 129 sqlSession.close(); 130 131
最下面的方法是学习<resultMap>标签所用的，上面的方法就是对t_customer表实现增删改查和现实的代码，其中第一个代码复用了MybatisUtils.java，后面的由于时间就没有。
Customer.xml
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 6 <!--namespace表示命名空间，唯一 --> 7 <mapper namespace="com.itheima.po.Customer"> 8 <!--resultType是返回值，parameterType是传入值 --> 9 <select id="findCustomerById" resultType="com.itheima.po.Customer" parameterType="Integer"> 10 select * from t_customer where id = #id 11 </select> 12 <!-- 模糊查询 --> 13 <!--防止sql注入，不用$value，用#id可以 --> 14 <select id="findCustomerByName" resultType="com.itheima.po.Customer" parameterType="String"> 15 select * from t_customer where username like concat(‘%‘,#username,‘%‘) 16 </select> 17 <insert id="addCustomer" parameterType="com.itheima.po.Customer"> 18 insert into t_customer(username,jobs,phone)values(#username,#jobs,#phone) 19 </insert> 20 <update id="updateCustomer" parameterType="com.itheima.po.Customer" > 21 update t_customer set username=#username,jobs=#jobs,phone=#phone where id=#id 22 </update> 23 <delete id="deleteCustomer" parameterType="Integer"> 24 delete from t_customer where id=#id 25 </delete> 26 </mapper>
mybatis-config.xml
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE configuration 3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 5 <configuration> 6 <properties resource="db.properties"></properties> 7 <!--配置环境，默认环境id为mysql --> 8 <environments default="mysql"> 9 <!--配置id为mysql的数据库环境 --> 10 <environment id="mysql"> 11 <!--使用jdbc的事务管理 --> 12 <transactionManager type="JDBC"/> 13 <!--数据库连接池 --> 14 <dataSource type="POOLED"> 15 <property name="driver" value="$jdbc.driver"/> 16 <property name="url" value="$jdbc.url"/> 17 <property name="username" value="$jdbc.username"/> 18 <property name="password" value="$jdbc.password"/> 19 </dataSource> 20 </environment> 21 </environments> 22 <!--可以配置多个mapper --> 23 <mappers> 24 <mapper resource="com/itheima/po/CustomerMapper.xml"/> 25 <mapper resource="com/itheima/po/UserMapper.xml"/> 26 </mappers> 27 </configuration>
db.properties
1 jdbc.driver=com.mysql.jdbc.Driver 2 jdbc.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=UTF-8 3 jdbc.username=root 4 jdbc.password=123456
log4j.properties
# Global logging configuration
log4j.rootLogger=ERROR, stdout
# MyBatis logging configuration...
log4j.logger.com.itheima=DEBUG
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
mybatis-config中将<mapper resource="com/itheima/po/UserMapper.xml"/>删除
就可以实现mybatis基本的增删改查了。
package com.itheima.test;
import java.io.IOException;import java.io.InputStream;import java.util.List;
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 org.junit.Test;
import com.itheima.po.Customer;import com.itheima.po.User;import com.itheima.utils.MybatisUtils;
//mybatis入门程序测试
public class MybatisTest @Testpublic void findCustomerById() throws IOException ////1.读取配置文件//String resourceString="mybatis-config.xml";//InputStream inputStream=Resources.getResourceAsStream(resourceString);////根据配置文件构建SqlSessionFactory//SqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream);////通过SqlSessionFactory创建sqlsession//SqlSession sqlSession=sessionFactory.openSession();////sqlSession执行映射文件中的sql语句，并返回结果////第一个参数为mapper.xml中的id，第二个是传入的占位符就是#id的值 SqlSession sqlSession=MybatisUtils.getSqlSession();Customer customer=sqlSession.selectOne("com.itheima.po.Customer.findCustomerById", 1);System.out.println(customer.toString());//关闭sqlsessionsqlSession.close();@Testpublic void findCustomerByName() throws IOException //1.读取配置文件String resource="mybatis-config.xml";InputStream inputStream=Resources.getResourceAsStream(resource);//根据配置文件构建SqlSessionFactorySqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream);//通过SqlSessionFactory创建sqlsessionSqlSession sqlSession=sessionFactory.openSession();List<Customer> customers= sqlSession.selectList("com.itheima.po.Customer.findCustomerByName","j");for (Customer customer:customers) System.out.println(customer.toString());sqlSession.close();@Testpublic void addCustomerTest() throws IOException //1.读取配置文件String resource="mybatis-config.xml";InputStream inputStream=Resources.getResourceAsStream(resource);//根据配置文件构建SqlSessionFactorySqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream);//通过SqlSessionFactory创建sqlsessionSqlSession sqlSession=sessionFactory.openSession();Customer customer=new Customer();customer.setUsername("zyk");customer.setJobs("hero");customer.setPhone("15035766618");int row=sqlSession.insert("com.itheima.po.Customer.addCustomer", customer);if(row>0) System.out.println("插入了"+row+"数据");else System.out.println("插入失败");//注意要提交事务，增删改都涉及到事务sqlSession.commit();sqlSession.close();@Testpublic void updateCustomerTest() throws IOException //1.读取配置文件String resource="mybatis-config.xml";InputStream inputStream=Resources.getResourceAsStream(resource);//根据配置文件构建SqlSessionFactorySqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream);//通过SqlSessionFactory创建sqlsessionSqlSession sqlSession=sessionFactory.openSession();Customer customer=new Customer();customer.setId(7);customer.setUsername("zyk1");customer.setJobs("student");customer.setPhone("15614141855");int row=sqlSession.update("com.itheima.po.Customer.updateCustomer", customer);if(row>0) System.out.println("修改成功");else System.out.println("修改失败");//注意要提交事务，增删改都涉及到事务sqlSession.commit();sqlSession.close();@Testpublic void deleteCustomerTest() throws IOException //1.读取配置文件String resource="mybatis-config.xml";InputStream inputStream=Resources.getResourceAsStream(resource);//根据配置文件构建SqlSessionFactorySqlSessionFactory sessionFactory=new SqlSessionFactoryBuilder().build(inputStream);//通过SqlSessionFactory创建sqlsessionSqlSession sqlSession=sessionFactory.openSession();int row=sqlSession.delete("com.itheima.po.Customer.deleteCustomer", 3);if(row>0) System.out.println("删除成功");else System.out.println("删除失败");//注意要提交事务，增删改都涉及到事务sqlSession.commit();sqlSession.close();@Testpublic void findAllUser() SqlSession sqlSession=MybatisUtils.getSqlSession();List<User> users= sqlSession.selectList("com.itheima.po.User.findAllUser");for(User user:users) System.out.println(user);sqlSession.close();
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