昨天的代码中，在成功编辑后，我们是无法看到里面数据的具体操作，解决方案则是在原来基础的加上一个log4j.properties（文件名不能错，这是一个坑，否则无法看到具体操作）,首先先看文件夹各个层级。（本次笔记尚未使用别名进行操作，其中java.lang.Long可以更改为long的别名）。
然后数据库各个分层次代码。
更新语句
查询一个对象的语句
查询所有对象的语句
删除对象的具体操作
具体代码（mybatieutils为一个方法）
mybatis.xml文件代码
<?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>
<environments default="default">
<environment id="default">
<transactionManager type="JDBC"></transactionManager>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis"></property>
<property name="username" value="root"></property>
<property name="password" value="123456"></property>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mybatis/domain/usermapper.xml"></mapper> //关联其他xml文件（执行对user类的对象操作）
</mappers>
</configuration>
usermapper.xml文件代码
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="mybatis.domain.usermapper">
<insert id="save" parameterType="mybatis.domain.user" keyColumn="id" keyProperty="id" useGeneratedKeys="true">
INSERT INTO user (username,password,age)VALUES (#{username},#{password},#{age})
</insert>
<update id="update" parameterType="mybatis.domain.user">
UPDATE user SET username=#{username},password=#{password},age=#{age} WHERE id=#{id}
</update>
<select id="search" parameterType="java.lang.Long" resultType="mybatis.domain.user"> //java.lang.Long可以更换为long
SELECT *FROM user WHERE id=#{id}
</select>
<select id="list" resultType="mybatis.domain.user">
SELECT *FROM user
</select>
<delete id="delete" parameterType="java.lang.Long">
DELETE FROM user WHERE id=#{id}
</delete>
</mapper>
mybatisutils工具类的编写
package mybatis.utils;
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 java.io.IOException;
public class mybatisutils {
private SqlSessionFactory sf;
private static mybatisutils instance=new mybatisutils();
public mybatisutils(){
try {
sf=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml"));
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession opensession(){
return instance.sf.openSession(); //静态方法不能直接调用非静态方法。
}
}
log4j.properties(注意文件名千万不能有错)
# Global logging configuration
log4j.rootLogger=ERROR, stdout
# MyBatis logging configuration...
log4j.logger.mybatis.domain.usermapper=TRACE //mybatis.domain.usermapper为具体操作数据库的那个xml所在的路径
# 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
user类
package mybatis.domain;
import lombok.Data;
public class user {
private Long id;
private String username;
private String password;
private Integer age;
public Long getId() {
return id;
}
public void setId(Long 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 Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "user{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", age=" + age +
'}';
}
}
usertest测试类
package mybatis.test;
import mybatis.domain.user;
import mybatis.utils.mybatisutils;
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 java.io.IOException;
import java.util.List;
public class usertest {
@Test
public void test() throws IOException {
user u=new user();
u.setAge(17);
u.setUsername("小李子");
u.setPassword("123456");
//SqlSessionFactory sf=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml"));
SqlSession session=mybatisutils.opensession();
session.insert("mybatis.domain.usermapper.save",u);
session.close();
System.out.println(u);
}
@Test
public void testupdate(){
user u=new user();
u.setAge(47);
u.setUsername("李公公");
u.setPassword("123");
u.setId(1L);
SqlSession session=mybatisutils.opensession();
session.update("mybatis.domain.usermapper.update",u);
session.close();
}
@Test
public void testget(){
SqlSession session=mybatisutils.opensession();
user u=session.selectOne("mybatis.domain.usermapper.search",1L);
System.out.println(u);
session.close();
}
@Test
public void testlist(){
SqlSession session=mybatisutils.opensession();
List<user>users=session.selectList("mybatis.domain.usermapper.list");
for (user user : users) {
System.out.println(user);
}
session.close();
}
@Test
public void testdelete(){
SqlSession session=mybatisutils.opensession();
session.delete("mybatis.domain.usermapper.delete",7L);
session.close();
}
}
测试结果如下图