Java开发之Mybatis框架

发布时间：2020-06-12 12:55:42 作者：专注地一哥
来源：网络阅读：581

mybasits配置文件书写
1.configer文件配置
<?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>

<settings>
<setting name="logImpl" value="LOG4J"/>
</settings>
<environments default="default"> 
<environment id="default">
<transactionManager type="JDBC" />
<dataSource type="POOLED"> 
<property name="driver" value="com.mysql.cj.jdbc.Driver" />
<property name="url" value="jdbc:mysql://127.0.0.1:3306/test4012?characterEncoding=utf8&serverTimezone=GMT"/>
<property name="username" value="root" />
<property name="password" value="root" />
</dataSource>
</environment>
</environments>

<mappers>
<mapper resource="com/pojo/usermapper-4012.xml" />
<mappers>
</configuration>
2.mapper文件配置
(1)resultType是返回值类型
（2）pramatetertype是传入的参数
<?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="com.service.IUserDao4012">



<select id="SelectAll" resultType="com.pojo.User4012">
SELECT * FROM table4012
limit #{offset},#{pagesize}
</select>

<insert id="InsertUser" parameterType="com.pojo.User4012">
insert into table4012(id,username,number,mybasits,android,javaee) values (#{id},#{username},#{number},#{mybasits},#{android},#{javaee})
</insert>
<delete id="DeleteUser" parameterType="com.pojo.User4012">
delete from table4012 where id=#{**}
</delete>
<update id="UpdateUser" parameterType="com.pojo.User4012">
update table4012 set username=#{username},number =#{number},mybasits=#{mybasits},android=#{android},javaee=#{javaee} where id=#{id}
</update>
<select id="findcount" parameterType="com.pojo.PageWays">
SELECT count () from table4012
</select>
<select id="findpage" parameterType="com.pojo.PageWays">
SELECT * from table4012
</select>
</mapper>
3.util类配置
package com.SelfStudy.util;
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.InputStream;
public class Util {
private static SqlSessionFactory build;//定义一个对象
static {
String s="mybatis.config.xml";//加载config文件
InputStream inputStream=null;//输入输出流
try {
inputStream= Resources.getResourceAsStream(s);
build=new SqlSessionFactoryBuilder().build(inputStream);
}
catch (Exception e){
e.printStackTrace();
}
finally {
try {
if ( inputStream !=null){
inputStream.close();
}
}catch (Exception e){
e.printStackTrace();
}
}
}
public static SqlSession getSession(){
return build.openSession();
}
}
4.log4j.properties文件配置
log4j.appender.console =org.apache.log4j.ConsoleAppender
log4j.appender.console.Target =System.out
log4j.appender.console.layout =org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern =[%-5p][%d{yyyy-MM-dd HH:mm:ss}] %c %L %m%n

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log4j.rootLogger =debug,console
##log4j.logger.com.mapper.StudentMapper=debug,console
四.动态sql
1.if set标签的使用
Select from table
if(test="name!=null and name!=''"){
#{id}
}
如果是数据库添加语句在每一句后面添加，
if(test="name!=null and name!=''"){
#{id}，
}
2.where标签的使用
Select from table
<where>
if(test="name!=null and name!=''"){
name=#{name}
}
如果是数据库添加语句在每一句后面添加，
if(test="id!=null and id!=''"){
id=#{id}
}
</where>
3.choose when标签的使用
<where>
<choose>
<when test="name!=null and name!=''">
and name=#{name}
</when>
<when></when>
</choose>
</where>

set标签的使用
uddate Table
set id=#{id}
<where>
<if></if>
</where>
trim标签的使用
<update id="upd" parameterType="Teacher">
update Teacher
<trim prefix="set" suffixOverrides=",">
name=#{name},age=#{age},
</trim>
where id=#{id}
</update>
prefix=“在前面进行添加”
prefixOverrides=“在前面进行去掉”
suffix=“在后面进行添加”
suffixOverrides=“在后面进行去掉”
重点:执行的顺序先去除再添加
bind标签
<bind nam="nam" valus="'%'+nam+'%'"></bind>
slct * from tabl wr nam lik #{nam}
foreach（集合查询，添加）
<foreach collecation="" open="" close="" item="">
insert into table () valuse
<if test="">
#{},
</if>
</foreach>
collection:传入的参数类型
open:打开方式
close：关闭方式
item:item
selectkey 的使用（查询上一条记录的一个属性）
<insert>
insert table valuse()
<selectkey keyproperty="" resulttype="" order="" keycolum=""></selectkey>
select last_insert_name()
</insert>
keypropert是查询的属性的名称
resulttype是XM代理申请www.fx61.com/brokerlist/xm.html返回值类型,是查询结果的返回值类型
order是执行顺序
keycolum:数据库中对应的属性
多种查询方法的使用
1.模糊查询
select from table where name=#{name}
[1]在查询的时候改正
SelectAll("%ko%");
[2]在sql语句中改正
使用concat函数
select from table where
id=concat('%',#{id},'%')
多表联合查询
(1) mapper文件的配置类

<resultMap id="SelectTogether01" type="com.SelfStudy.pojo.PeopleWithDatil">//封装连接类的属性，主要是主类属性
<id property="detailid" column="id"></id>
<result property="address" column="address"></result>
<result property="country" column="country"></result>
<result property="city" column="city"></result>
<association property="PeopleDatil" javaType="com.SelfStudy.pojo.People">//用association封装子类所有的属性
<id property="detailid" column="id"></id>
<result property="name" column="name"></result>
<result property="phone" column="phone"></result>
</association>
</resultMap>
<select id="SelectTogether" resultMap="SelectTogether01">
SELECT * FROM people ,peopledatil//联合查询，动态sql
<where>
people.id=peopledatil.id
</where>
</select>
(2) test测试类@org.junit.Test
br/>@org.junit.Test
SqlSession session=Util.getSession();
PeopleMapperDao peopleMapperDao=session.getMapper(PeopleMapperDao.class);
peopleMapperDao.SelectTogether();
List<People> list=null;
list=peopleMapperDao.SelectTogether();
System.out.println(list);
}
3.一对一联合查询
配置类文件
package com.pojo;
public class Student {
private String name;
private Integer id;
private Integer tid;//和老师中的id对因
private String address;
private String city;
//一个学生对应一个老师
private Teacher teacher;//在学生中查询老师
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getTid() {
return tid;
}
public void setTid(Integer tid) {
this.tid = tid;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public Teacher getTeacher() {
return teacher;
}
public void setTeacher(Teacher teacher) {
this.teacher = teacher;
}
public Student(String name, Integer id, Integer tid, String address, String city, Teacher teacher) {
this.name = name;
this.id = id;
this.tid = tid;
this.address = address;
this.city = city;
this.teacher = teacher;
}
public Student() { }@Override
br/>@Override
return "Student{" +
"name='" + name + '\'' +
", id=" + id +
", tid=" + tid +
", address='" + address + '\'' +
", city='" + city + '\'' +
", teacher=" + teacher +
'}';
}
}
接口配置
package com.service;
import com.pojo.Student;
import java.util.List;
public interface StudentDao {
public List<Student> Selectall();
public List<Student> SelectByid(Integer id);
//查询所有学生
public List<Student> SelectAllStudent();
public List<Student> selct01();
}
mapper文件配置
<?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="com.service.StudentDao">
<resultMap id="map" type="com.pojo.Student">
<id column="id" property="id"></id>
<result property="name" column="name"></result>
<result property="address" column="address"></result>
<result property="city" column="city"></result>
<result property="tid" column="tid"></result>
<association property="teacher" column="tid" select="com.service.TeacherDao.SelectByid"></association>
</resultMap>

<select id="selct01" resultType="com.pojo.Student">
SELECT s.name, s.id ,s.tid ,s.address , s.city ,t.name , school ,age , sex,t.id
FROM student s LEFT JOIN teacher t on
s.tid=t.id
</select>
4.多对一联合查询
<resultMap id="map01" type="com.pojo.Teacher">
<id property="id1" column="id1" ></id>
<result column="name1" property="name1"></result>
<result column="school" property="school"></result>
<result column="age" property="age"></result>
<result column="sex" property="sex"></result>
<collection property="students" ofType="com.pojo.Student">
<id column="id" property="id"></id>
<result column="name" property="name"></result>
<result column="tid" property="tid"></result>
<result column="address" property="address"></result>
<result column="city" property="city"></result>
</collection>
</resultMap>
多对多的联合查询
实体类的配置
package com.pojo;
import java.util.Date;
import java.util.List;
public class Writer {
private String name;
private Integer id;
private Integer age;
private String sex;
private String book;
private Date birthday;
//查询作者里面包含作品
private List<Works> works;
public List<Works> getWorks() {
return works;
}
public void setWorks(List<Works> works) {
this.works = works;
}
public Writer(List<Works> works) {
this.works = works;}
@Override
br/>}
@Override
return "Writer{" +
"name='" + name + '\'' +
", id=" + id +
", age=" + age +
", sex='" + sex + '\'' +
", book='" + book + '\'' +
", birthday=" + birthday +
", works=" + works +
'}';
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getBook() {
return book;
}
public void setBook(String book) {
this.book = book;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public Writer(String name, Integer id, Integer age, String sex, String book, Date birthday) {
this.name = name;
this.id = id;
this.age = age;
this.sex = sex;
this.book = book;
this.birthday = birthday;
}
public Writer() { }
}
mapper文件配置
<?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="com.service.WriterDao">

<select id="SelectAllWriter" resultType="com.pojo.Writer">
select from writer w
</select>
<select id="SelectWriterByid" resultType="com.pojo.Writer">
select from writer w
<where>
id=#{id}
</where>
</select>
<resultMap id="map01" type="com.pojo.Writer">
<id property="id" column="id"></id>
<result column="name" property="name"></result>
<result column="age" property="age"></result>
<result column="sex" property="sex"></result>
<result column="book" property="book"></result>
<result column="birthday" property="birthday"></result>
<collection property="works" ofType="com.pojo.Works">
<id property="book_id" column="book_id"></id>
<id property="book_name" column="book_name"></id>
<id property="book_press" column="book_press"></id>
<id property="press_date" column="press_date"></id>
</collection>
</resultMap>
<select id="SelectAllWriterAndWorks" resultMap="map01">
SELECT w.age,w.birthday,w.book,w.id,w.name,w.sex ,o.book_id,o.book_press,o.press_date,o.book_name
FROM writer w LEFT JOIN information i ON w.id=i.writer_idLEFT JOIN works o ON o.book_id=i.works_id</select>
</mapper>
注解方式配置
@Results(value={
br/></select>
</mapper>
注解方式配置
@Results(value={
br/>@Result(column="",property=""),
br/>@Result(column="",property=""),
br/>@Result(column="",property=""),
@Select(".......")
br/>})
@Select(".......")
导入包
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.17</version>
</dependency>

<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>
//导入依赖
2.构建方法
public class ImportExcel {
//导入excel文件的方法
public void ReadExcel(File file){
List<String> list=new ArrayList<>();
//1.传入需要导入的Excel文件的路径
try{
//2.读取文件的内容
HSSFWorkbook workbook=new HSSFWorkbook(FileUtils.openInputStream(file));
//3.读取文件的sheet页,sheet就是Excel中的每一张表，也就是workboo的sheet页
HSSFSheet sheet=workbook.getSheetAt(0);
//4.开始读取表的内容
int startline=0;//起始行的行数，也就是从0 到最后一行
int endline=sheet.getLastRowNum()+1;//最后一行d的下表
//遍历每一行
Map<Integer,Map<Integer,Object>> map=new HashMap<>();
//第一行，第一列，值
//遍历行
for (int a=1;a<endline;a++){
HSSFRow hssfRow=sheet.getRow(a);
//遍历列
//写一个集合存储列和值
Map<Integer,Object> result=new HashMap<>();
int endcell=hssfRow.getLastCellNum();
for (int j=0;j<endcell;j++){
result.put(j, hssfRow.getCell(j));//用行数去获取列
}
map.put(a, result);
}
List<People> list1=new ArrayList<>();
for (Integer xxx:map.keySet()){
System.out.print(map.get(xxx).get(0));
System.out.print(map.get(xxx).get(1));
System.out.print(map.get(xxx).get(2));
System.out.print(map.get(xxx).get(3));
People people=new People();
people.setName(String.valueOf(map.get(xxx).get(0)));
String java=String.valueOf(map.get(xxx).get(1));
Integer java1=Integer.parseInt(java.substring(0, java.indexOf(".")));
people.setJava(java1);
String mybas=String.valueOf(map.get(xxx).get(2));
Integer mybas1=Integer.parseInt(mybas.substring(0, mybas.indexOf(".")));
people.setMybas(mybas1);
String androi=String.valueOf(map.get(xxx).get(3));
Integer androi1=Integer.parseInt(androi.substring(0, androi.indexOf(".")));
people.setAndroi(androi1);
list1.add(people);
}
SqlSession session= Util.getSession();
PeopleMapperDao peopleMapperDao=session.getMapper(PeopleMapperDao.class);
peopleMapperDao.ExcelInsert(list1);
session.commit();
}
catch (Exception e){
e.printStackTrace();
}
}
}
调用方法@org.junit.Test
br/>@org.junit.Test
ImportExcel aaa=new ImportExcel();
File file=new File("C:/Users/lenovo/Desktop/study/ssm笔记/test4012.xls");
aaa.ReadExcel(file);
}

Java开发之Mybatis框架

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