項目實現的功能

查詢所有用戶信息
通過Id查詢用戶信息
添加用戶（回顯主鍵）
修改用戶信息
刪除用戶信息
通過用戶名字模糊查詢

一、引入依賴和工程結構

<?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>com.william</groupId><artifactId>MybatisMapper</artifactId><version>1.0-SNAPSHOT</version><properties><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.5</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency></dependencies></project>

二、創建實體類

User

package com.william.domain;import java.util.Date;/*** @author ：lijunxuan* @date ：Created in 2019/7/9 19:28* @description ：* @version: 1.0*/ public class User {private Integer id;private String username;private String password;private String sex;private Date birthday;@Overridepublic String toString() {return "User{" +"id=" + id +", username='" + username + '\'' +", password='" + password + '\'' +", sex='" + sex + '\'' +", birthday=" + birthday +'}';}public Date getBirthday() {return birthday;}public void setBirthday(Date birthday) {this.birthday = birthday;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}}

三、映射文件

1.UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.william.dao.UserMapper"><!--查詢所有用戶信息--><select id="findAll" resultType="com.william.domain.User">select * from user</select><!--通過ID查詢用戶信息--><select id="findById" parameterType="java.lang.Integer" resultType="com.william.domain.User">select * from user where id=#{id}</select><!--模糊查詢--><select id="findByUsername" parameterType="java.lang.String" resultType="com.william.domain.User">select * from user where username like "%"#{value}"%"</select><!--增加用戶信息 主鍵回顯--><insert id="insert" parameterType="com.william.domain.User"> -- selectKey: 查詢主鍵值 -- resultType： 主鍵類型 -- keyColumn: 指定主鍵的列名 -- keyProperty: 主鍵對應的屬性名 -- order:可選值：after ，before -- AFTER: 在執行sql語句之后執行查找主鍵操作 -- BEFORE: 在執行sql語句之前執行查找主鍵操作<selectKey resultType="java.lang.Integer" keyColumn="id" keyProperty="id" order="AFTER" >select last_insert_id()</selectKey>insert into user values (null ,#{username},#{password},#{sex},#{birthday})</insert><!--更新用戶信息--><update id="update" parameterType="com.william.domain.User">update user set username=#{username},password=#{password},sex=#{sex},birthday=#{birthday} where id=#{id}</update><!--刪除用戶信息--><delete id="delete" parameterType="java.lang.Integer">delete from user where id =#{id}</delete> </mapper>

四、引入log4j

log4j.properties

# Set root category priority to INFO and its only appender to CONSOLE. #log4j.rootCategory=INFO, CONSOLE debug info warn error fatal log4j.rootCategory=debug, CONSOLE, LOGFILE, info# Set the enterprise logger category to FATAL and its only appender to CONSOLE. log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE# CONSOLE is set to be a ConsoleAppender using a PatternLayout. log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n# LOGFILE is set to be a File appender using a PatternLayout. log4j.appender.LOGFILE=org.apache.log4j.FileAppender log4j.appender.LOGFILE.File=d:\axis.log log4j.appender.LOGFILE.Append=true log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

五、測試類

TestCrud

package com.william;import com.william.dao.UserMapper; import com.william.domain.User; 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 javax.annotation.Resource; import java.io.IOException; import java.io.InputStream; import java.util.List;/*** @author ：lijunxuan* @date ：Created in 2019/7/12 10:16* @description ：* @version: 1.0*/ public class TestCrud {/*** 查詢所有用戶信息* @throws IOException*/@Testpublic void findAll() throws IOException {InputStream inputStream = Resources.getResourceAsStream("Mybatis-configuration.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = sqlSessionFactory.openSession();//獲取某接口的動態代理對象（獲取某接口的一個實現類）UserMapper userMapper = sqlSession.getMapper(UserMapper.class);List<User> userList = userMapper.findAll();for (User user : userList) {System.out.println(user);}sqlSession.close();}/****通過Id查詢用戶信息* @throws IOException*/@Testpublic void findById() throws IOException {InputStream inputStream = Resources.getResourceAsStream("Mybatis-configuration.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = sqlSessionFactory.openSession();//獲取某接口的動態代理對象（獲取某接口的一個實現類）UserMapper userMapper = sqlSession.getMapper(UserMapper.class);User findByIdUser = userMapper.findById(43);System.out.println(findByIdUser);sqlSession.close();}/*** 模糊查詢* 通過用戶名模糊查詢* @throws IOException*/@Testpublic void findByUsername() throws IOException {InputStream inputStream = Resources.getResourceAsStream("Mybatis-configuration.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = sqlSessionFactory.openSession();//獲取某接口的動態代理對象（獲取某接口的一個實現類）UserMapper userMapper = sqlSession.getMapper(UserMapper.class);List<User> findByIdUsernameList = userMapper.findByUsername("a");for (User user : findByIdUsernameList) {System.out.println(user);}sqlSession.close();}/*** 增加用戶信息* @throws IOException*/@Testpublic void insert() throws IOException {InputStream inputStream = Resources.getResourceAsStream("Mybatis-configuration.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = sqlSessionFactory.openSession();//獲取某接口的動態代理對象（獲取某接口的一個實現類）UserMapper userMapper = sqlSession.getMapper(UserMapper.class);User user= new User();user.setUsername("today");user.setPassword("hello");user.setSex("女");userMapper. insert(user);//事務提交sqlSession.commit();System.out.println("添加后用戶的id為："+user.getId());sqlSession.close();}/*** 更新用戶信息* @throws IOException*/@Testpublic void update() throws IOException {InputStream inputStream = Resources.getResourceAsStream("Mybatis-configuration.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = sqlSessionFactory.openSession();//獲取某接口的動態代理對象（獲取某接口的一個實現類）UserMapper userMapper = sqlSession.getMapper(UserMapper.class);User user= new User();user.setId(45);user.setUsername("today");user.setPassword("hello");user.setSex("女");userMapper. update(user);//事務提交sqlSession.commit();sqlSession.close();}/*** 通過id刪除用戶信息* @throws IOException*/@Testpublic void delete() throws IOException {InputStream inputStream = Resources.getResourceAsStream("Mybatis-configuration.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = sqlSessionFactory.openSession();//獲取某接口的動態代理對象（獲取某接口的一個實現類）UserMapper userMapper = sqlSession.getMapper(UserMapper.class);userMapper. delete(50);//事務提交sqlSession.commit();sqlSession.close();} }

【重點】mybatis動態代理模式開發的要求

1.dao接口和映射文件必須路徑相同，文件名相同(dao接口和映射文件必須在同一個文件夾中，文件名必須相同)

如圖所示：

2.namespace必須是 接口的全限定類名

3.映射文件中的id值必須是接口的方法名

4.參數類型和返回值類也必須是匹配的

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