SpringBoot2（Spring Boot 的Web开发 springMVC 请求处理 参数绑定 常用注解 数据传递 文件上传）
一、Spring Boot的Web开发
1.静态资源映射规则
总结：只要静态资源放在类路径下：
called /static (or /public or /resources or //METAINF/resources
一启动服务器就能访问到静态资源文件
springboot只需要将图片放在 static 下 就可以被访问到了
** 总结： **
只要静态资源放在类路径下： called /static (or INF/resources
访问 ： 当前项目根路径/ + 静态资源名
**静态资源访问前缀 **
spring:
mvc:
static-path-pattern: static/test/**
2.enjoy模板引擎
“四个步骤”
1.添加坐标
<dependency>
<groupId>com.jfinal</groupId>
<artifactId>enjoy</artifactId>
<version>5.0.3</version>
</dependency>
2.开启配置
package com.stringzhua.springboot_web_demo01.config;
import com.jfinal.template.Engine;
import com.jfinal.template.ext.spring.JFinalViewResolver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class SpringBootConfig {
@Bean(name = "jfinalViewResolver")
public JFinalViewResolver getJFinalViewResolver() {
// 创建用于整合 spring boot 的 ViewResolver 扩展对象
JFinalViewResolver jfr = new JFinalViewResolver();
// 对 spring boot 进行配置
jfr.setSuffix(".html");
jfr.setContentType("text/html;charset=UTF-8");
jfr.setOrder(0);
// 设置在模板中可通过 #(session.value) 访问 session 中的数据
jfr.setSessionInView(true);
// 获取 engine 对象，对 enjoy 模板引擎进行配置，配置方式与前面章节完全一样
Engine engine = JFinalViewResolver.engine;
// 热加载配置能对后续配置产生影响，需要放在最前面
engine.setDevMode(true);
// 使用 ClassPathSourceFactory 从 class path 与 jar 包中加载模板文件
engine.setToClassPathSourceFactory();
// 在使用 ClassPathSourceFactory 时要使用 setBaseTemplatePath
// 代替 jfr.setPrefix("/view/")
engine.setBaseTemplatePath("/templates/");
// 更多配置与前面章节完全一样
// engine.addDirective(...)
// engine.addSharedMethod(...);
return jfr;
}
}
3.将页面保存在templates目录下
4.编写代码
Spring整合mybatis-plus
“四步”
1.导入坐标
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.3</version>
</dependency>
<!-- <dependency>-->
<!-- <groupId>org.mybatis.spring.boot</groupId>-->
<!-- <artifactId>mybatis-spring-boot-starter</artifactId>-->
<!-- <version>2.2.2</version>-->
<!-- </dependency>-->
2.编写配置实体类与关系表映射关系
package com.stringzhua.springboot_mybatis_demo01.pojo;
import com.baomidou.mybatisplus.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import java.io.Serializable;
/**
* @Author Stringzhua
* @Date 2024/9/19 17:21
* description:
*/
@TableName(value = "student")
public class Student implements Serializable {
@TableId(value = "stu_id", type = IdType.AUTO)
private int stuId;
@TableField(value = "stu_name")
private String stuName;
@TableField(value = "nick_name")
private String nickName;
@TableField(value = "stu_age")
private int stuAge;
//逻辑查询
@TableLogic(value = "0", delval = "1")
private int isDelete;
//数据库无关字段
@TableField(exist = false)
private MultipartFile file;
@Override
public String toString() {
return "Student{" +
"stuId=" + stuId +
", stuName='" + stuName + '\'' +
", nickName='" + nickName + '\'' +
", stuAge=" + stuAge +
'}';
}
public int getStuId() {
return stuId;
}
public void setStuId(int stuId) {
this.stuId = stuId;
}
public String getStuName() {
return stuName;
}
public void setStuName(String stuName) {
this.stuName = stuName;
}
public String getNickName() {
return nickName;
}
public void setNickName(String nickName) {
this.nickName = nickName;
}
public int getStuAge() {
return stuAge;
}
public void setStuAge(int stuAge) {
this.stuAge = stuAge;
}
public Student() {
}
public Student(String stuName, String nickName, int stuAge) {
this.stuName = stuName;
this.nickName = nickName;
this.stuAge = stuAge;
}
}
3.1使用公共的数据访问层
@Mapper
public interface StudentMapper extends BaseMapper<Student> {
@Select("select * from student")
public List<Student> selectAll();
}
3.2使用公共业务层
4.编写配置文件
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/mavendb?serverTimezone=Asia/Shanghai
username: root
password: 12345678
mybatis:
configuration:
map-underscore-to-camel-case: true
mybatis-plus:
configuration:
map-underscore-to-camel-case: true
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #日志
mybatis-plus的增删改查：
@SpringBootTest
public class Test01 {
@Autowired(required = false)
StudentMapper studentMapper;
//新增
@Test
public void add() {
Student student = new Student("一猫人", "大熊猫本猫", 3);
int count = studentMapper.insert(student);
System.out.println("主键回填" + student.getStuId());
System.out.println("影响的行数" + count);
}
//根据学生id修改
@Test
public void modifyById() {
Student student = new Student();
student.setStuId(12);
student.setStuName("李前");
student.setStuAge(18);
int count = studentMapper.updateById(student);
System.out.println("影响行数" + count);
}
//根据姓名修改,条件
@Test
public void modifyByName() {
//1.修改数据
Student student = new Student();
student.setNickName("猫眼电影");
student.setStuAge(18);
//2.创建条件
QueryWrapper<Student> wrapper = new QueryWrapper<>();
wrapper.eq("stu_name", "猫猫");
//3.执行sql
studentMapper.update(student, wrapper);
}
//根据学生id查询
@Test
public void selectById() {
Student student = studentMapper.selectById(10);
System.out.println(student);
}
//根据多个学生id查询
@Test
public void selectByMoreId() {
List<Student> students = studentMapper.selectBatchIds(Arrays.asList(1, 2, 3, 4, 5, 6));
for (int i = 0; i < students.size(); i++) {
Student student = students.get(i);
System.out.println(student);
}
}
//查询count
@Test
public void selectCount() {
QueryWrapper<Student> wrapper = new QueryWrapper<>();
wrapper.eq("stu_name", "猫猫");
// int count = studentMapper.selectCount(null);//全查
int count = studentMapper.selectCount(wrapper);//条件查询
System.out.println(count);
}
//条件查询
@Test
public void selectByCondition() {
QueryWrapper<Student> wrapper = new QueryWrapper<>();
// wrapper.eq("stu_name","猫猫");//相当于这里有个and
// wrapper.eq("nick_name","猫眼电影");
//or查询
wrapper.eq("stu_name", "猫猫").or().eq("nick_name", "猫眼电影");
List<Student> list = studentMapper.selectList(wrapper);
for (int i = 0; i < list.size(); i++) {
Student student = list.get(i);
System.out.println(student);
}
}
}
mybatis-plus的分页插件[自带]
package com.stringzhua.springboot_mybatis_demo01.config;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* @Author Stringzhua
* @Date 2024/9/20 12:10
* description:
*/
@Configuration
public class MyBatisConfig {
//注入mp拦截器
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor(){
//1.实例化拦截器
MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
//2.分页拦截器
mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor());
return mybatisPlusInterceptor;
}
}
@SpringBootTest
public class Test01 {
@Autowired(required = false)
StudentMapper studentMapper;
/**
* mp分页使用
* 注意：
* 1.page.setCurrent(2);当前页码从1开始
* 2.mybatis分页需要配置插件,mp不用
*/
//这里为逻辑分页
@Test
public void Page() {
//1.定义分页规则
Page<Student> page = new Page<>();
page.setSize(4);//每页记录数
page.setCurrent(2);//当前页码
//2.条件查询(可选)
QueryWrapper queryWrapper = new QueryWrapper();
queryWrapper.eq("stu_sex", "男");
Page<Student> iPage = studentMapper.selectPage(page, null);
List<Student> list = iPage.getRecords();
System.out.println("总记录数" + iPage.getTotal());
System.out.println("总记页数" + iPage.getPages());
for (int i = 0; i < list.size(); i++) {
Student student = list.get(i);
System.out.println(student);
}
}
//逻辑删除
//数据库中只是把is_delete设置为1,mp查询时默认查询为0字段的
//这里用mp查询时只有12条记录
@Test
public void deleteById() {
int count = studentMapper.deleteById(13);
System.out.println("影响的行数" + count);
}
//这里用mp查询时只有12条记录
@Test
public void selectAll() {
//queryWrapper为null,则没有查询条件,为全查
List<Student> list = studentMapper.selectList(null);
for (int i = 0; i < list.size(); i++) {
Student student = list.get(i);
System.out.println(student);
}
}
}
这里使用mp进行全查，则为12条记录，原因是mp走@TableLogic注解时，走的是查询表中is_delete字段为0的值。
//逻辑查询
@TableLogic(value = "0", delval = "1")
private int isDelete;
这里使用mybatis进行全查，则为13条记录
package com.stringzhua.springboot_mybatis_demo01;
import com.stringzhua.springboot_mybatis_demo01.mapper.StudentMapper;
import com.stringzhua.springboot_mybatis_demo01.pojo.Student;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.util.List;
@SpringBootTest
class SpringbootMybatisDemo01ApplicationTests {
@Autowired(required = false)
StudentMapper studentMapper;
//如果是mybatis的话,走自己写的sql,则是全查,相当于count(*)
//13条记录
@Test
void test01() {
List<Student> students = studentMapper.selectAll();
for (int i = 0; i < students.size(); i++) {
Student student = students.get(i);
System.out.println(student);
}
}
}
