Java第三十七天，Mybatis框架系列，基于单表操作的注解开发
一、常用注解
- @Insert:实现新增
- @Update:实现更新
- @Delete:实现删除
- @Select:实现查询
- @Result:实现结果集封装
- @Results:可以与@Result 一起使用，封装多个结果集
- @ResultMap:实现引用@Results 定义的封装
- @One:实现一对一结果集封装
- @Many:实现一对多结果集封装
- @SelectProvider: 实现动态 SQL 映射
- @CacheNamespace:实现注解二级缓存的使用
二、注解和配置文件的关联与注意事项
1.关联
因为配置文件中提供的关键信息，注解中同样可以提供；因此通过配置文件实现的功能，注解同样可以实现
（1）配置文件
（2）注解
2.注意事项
只要你使用注解开发 mybatis ，但是配置文件路径下同时包含了 xml 配置文件（路径名和文件名一致），此时，不管你用不用配置文件，mybatis 都会报错
三、项目实战
1.新建 Maven 项目，在 pom.xml 配置文件中设置打包方式，并且导入相关依赖
<?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>com.lanyue</groupId>
<artifactId>day04_eesy_03annotation_mybatis</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.12</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.10</version>
</dependency>
</dependencies>
</project>2.新建实体类，并且实现序列化接口
package com.lanyue.domain;
import java.io.Serializable;
import java.util.Date;
public class User implements Serializable{
private Integer id;
private String username;
private String address;
private String sex;
private Date 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 getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", address='" + address + '\'' +
", sex='" + sex + '\'' +
", birthday=" + birthday +
'}';
}
}
3.新建功能接口类
package com.lanyue.dao;
import com.lanyue.domain.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import java.util.List;
public interface IUserDao {
/**
* 查询所有用户
* @return
*/
@Select("select * from user")
List<User> findAll();
/**
* 保存用户
* @param user
*/
@Insert("insert into user(username,address,sex,birthday)values(#{username},#{address},#{sex},#{birthday})")
void saveUser(User user);
/**
* 更新用户
* @param user
*/
@Update("update user set username=#{username},sex=#{sex},birthday=#{birthday},address=#{address} where id=#{id}")
void updateUser(User user);
/**
* 删除用户
* @param userId
*/
@Delete("delete from user where id=#{id} ")
void deleteUser(Integer userId);
/**
* 根据id查询用户
* @param userId
* @return
*/
@Select("select * from user where id=#{id} ")
User findById(Integer userId);
/**
* 根据用户名称模糊查询
* @param username
* @return
*/
// @Select("select * from user where username like #{username} ")
@Select("select * from user where username like '%${value}%' ")
List<User> findUserByName(String username);
/**
* 查询总用户数量
* @return
*/
@Select("select count(*) from user ")
int findTotalUser();
}
4.新建并编辑 jdbc.properties 配置文件，填写连接数据库关键信息
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=1234565.新建并编辑 SqlMapConfig.xml配置文件；填写 mybatis 数据库配置信息
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 引入外部配置文件-->
<properties resource="jdbcConfig.properties"></properties>
<!--配置别名；指向实体类的所在位置-->
<typeAliases>
<package name="com.lanyue.domain"></package>
</typeAliases>
<!-- 配置环境-->
<environments default="mysql">
<environment id="mysql">
<transactionManager type="JDBC"></transactionManager>
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</dataSource>
</environment>
</environments>
<!-- 指定带有注解的dao接口（功能）所在位置 -->
<mappers>
<mapper class="com.lanyue.dao.IUserDao"></mapper>
</mappers>
</configuration>6.新建并编辑日志配置文件 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
# 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\n7.编写测试入口类
package com.lanyue.test;
import com.lanyue.dao.IUserDao;
import com.lanyue.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.After;
import org.junit.Before;
import org.junit.Test;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
public class AnnotationCRUDTest {
private InputStream in;
private SqlSessionFactory factory;
private SqlSession session;
private IUserDao userDao;
@Before
public void init() throws Exception {
in = Resources.getResourceAsStream("SqlMapConfig.xml");
factory = new SqlSessionFactoryBuilder().build(in);
session = factory.openSession();
userDao = session.getMapper(IUserDao.class);
}
@After
public void destroy() throws Exception {
session.commit();
session.close();
in.close();
}
// 增加
@Test
public void testSave() {
User user = new User();
user.setUsername("mybatis annotation");
user.setAddress("北京市昌平区");
userDao.saveUser(user);
}
// 删除
@Test
public void testDelete() {
userDao.deleteUser(45);
}
// 查找所有
@Test
public void listAll() {
List<User> all = userDao.findAll();
for (User user : all){
System.out.println(user.toString());
}
}
// 查找一个
@Test
public void testFindOne() {
User user = userDao.findById(45);
System.out.println(user);
}
// 根据名字查找
@Test
public void testFindByName() {
// List<User> users = userDao.findUserByName("%mybatis%");
List<User> users = userDao.findUserByName("传智播客");
for (User user : users) {
System.out.println(user);
}
}
// 查找数量
@Test
public void testFindTotal() {
int total = userDao.findTotalUser();
System.out.println(total);
}
// 更新
@Test
public void testUpdate() {
User user = new User();
user.setId(57);
user.setUsername("mybatis annotation update");
user.setAddress("北京市海淀区");
user.setSex("男");
user.setBirthday(new Date());
userDao.updateUser(user);
}
}
7.项目结构
