SpringBoot笔记

Spring Boot

Spring Boot 是⼀个快速开发框架，可以迅速搭建出⼀套基于 Spring 框架体系的应⽤，是 SpringCloud 的基础。

Spring Boot 开启了各种⾃动装配，从⽽简化代码的开发，不需要编写各种配置⽂件，只需要引⼊相关依赖就可以迅速搭建⼀个应⽤。

• 特点

1、不需要 web.xml

2、不需要 springmvc.xml

3、不需要 tomcat，Spring Boot 内嵌了 tomcat

4、不需要配置 JSON 解析，⽀持 REST 架构

5、个性化配置⾮常简单

• 如何使⽤

1、创建 Maven ⼯程，导⼊相关依赖。

org.springframework.boot

spring-boot-starter-parent

2.0.7.RELEASE

org.springframework.boot

spring-boot-starter-web

org.projectlombok

lombok

1.18.6

provided

2、创建 Student 实体类

package com.val.entity;

import lombok.Data;

@Data

public class Student {

private long id;

private String name;

private int age;

}

3、StudentRepository

package com.val.repository;

import com.val.entity.Student;

import java.util.Collection;

public interface StudentRepository {

public Collection findAll();

public Student findById(long id);

public void saveOrUpdate(Student student);

public void deleteById(long id);

}

4、StudentRepositoryImpl

package com.val.repository.impl;

import com.val.entity.Student;

import com.val.repository.StudentRepository;

import org.springframework.stereotype.Repository;

import java.util.Collection;

import java.util.HashMap;

import java.util.Map;

@Repository

public class StudentRepositoryImpl implements StudentRepository {

private static Map studentMap;

static{

studentMap = new HashMap<>();

studentMap.put(1L,new Student(1L,"张三",22));

studentMap.put(2L,new Student(2L,"李四",23));

studentMap.put(3L,new Student(3L,"王五",24)); }

@Override

public Collection findAll() {

return studentMap.values();

}

@Override

public Student findById(long id) {

return studentMap.get(id);

}

@Override

public void saveOrUpdate(Student student) {

studentMap.put(student.getId(),student);

}

@Override

public void deleteById(long id) {

studentMap.remove(id);

}

}

5、StudentHandler

package com.val.controller;

import com.val.entity.Student;

import com.val.repository.StudentRepository;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.*;

import java.util.Collection;

@RestController

@RequestMapping("/student")

public class StudentHandler {

@Autowired

private StudentRepository studentRepository;

@GetMapping("/findAll")

public Collection findAll(){

return studentRepository.findAll();

}

@GetMapping("/findById/{id}")

public Student findById(@PathVariable("id") long id){

return studentRepository.findById(id);

6、application.yml

server:

port: 9090

7、启动类

package com.val;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

public class Application {

public static void main(String[] args) {

SpringApplication.run(Application.class,args);

}

}

　　@SpringBootApplication 表示当前类是 Spring Boot 的⼊⼝，Application 类的存放位置必须是其他

　　相关业务类的存放位置的⽗级。

 

Spring Boot 整合 JSP

 

• pom.xml

org.springframework.boot

spring-boot-starter-parent

2.0.7.RELEASE

org.springframework.boot

spring-boot-starter-web

org.springframework.boot

spring-boot-starter-tomcat

org.apache.tomcat.embed

tomcat-embed-jasper

jstl

jstl

1.2

org.projectlombok

lombok

1.18.6

provided

 

• 创建配置⽂件 application.yml　　

 

 

• 创建 Handler

package com.val.controller;import com.southwind.entity.Student;

import com.val.repository.StudentRepository;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

@RequestMapping("/hello")

public class HelloHandler {

@Autowired

private StudentRepository studentRepository;

@GetMapping("/index")

public ModelAndView index(){

ModelAndView modelAndView = new ModelAndView();

modelAndView.setViewName("index");

modelAndView.addObject("list",studentRepository.findAll());

return modelAndView;

}

@GetMapping("/deleteById/{id}")

public String deleteById(@PathVariable("id") long id){

studentRepository.deleteById(id);

return "redirect:/hello/index";

}

@PostMapping("/save")

public String save(Student student){

studentRepository.saveOrUpdate(student);

return "redirect:/hello/index";

}

@PostMapping("/update")

public String update(Student student){

studentRepository.saveOrUpdate(student);

return "redirect:/hello/index";

}

@GetMapping("/findById/{id}")

public ModelAndView findById(@PathVariable("id") long id){

ModelAndView modelAndView = new ModelAndView();

modelAndView.setViewName("update");

modelAndView.addObject("student",studentRepository.findById(id));

return modelAndView; }

}

• JSP

<%--

Created by IntelliJ IDEA.

Date: 2020-06-12

Time: 12:02

To change this template use File | Settings | File Templates.

--%>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<%@ page isELIgnored="false" %>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

　　

　　

学⽣信息

　　

　　　　

　　　　

　　　　

　　　　　　

　　　　　　　　 

　　　　　　　

　　　　　　

　　　　

学⽣编号	学⽣姓名	学⽣年龄	操作
${student.id}	${student.name}	${student.age}	修改 删除

　　　　添加学⽣

<%--

Created by IntelliJ IDEA.Spring Boot HTML

Spring Boot 可以结合 Thymeleaf 模版来整合 HTML，使⽤原⽣的 HTML 作为视图。

User: val

Date: 2020-06-12

Time: 12:09

To change this template use File | Settings | File Templates.

--%>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

ID:

name:

age:

 

<%--

Created by IntelliJ IDEA.

User: val

Date: 2020-06-12

Time: 12:09

To change this template use File | Settings | File Templates.

--%>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

ID:

name:

age:

 

Spring Boot HTML

 

Spring Boot 可以结合 Thymeleaf 模版来整合 HTML，使⽤原⽣的 HTML 作为视图。

Thymeleaf 模版是⾯向 Web 和独⽴环境的 Java 模版引擎，能够处理 HTML、XML、JavaScript、CSS

等。

• pom.xml

org.springframework.boot

spring-boot-starter-parent

2.0.7.RELEASE

org.springframework.boot

spring-boot-starter-web

org.projectlombok

lombok

1.18.6

provided

org.springframework.boot

spring-boot-starter-thymeleaf

• appliction.yml

server:

port: 9090

spring:

thymeleaf:

prefix: classpath:/templates/

suffix: .html

mode: HTML5

encoding: UTF-8

• Handler

package com.val.controller;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RequestMapping;

@Controller

@RequestMapping("/index")

public class IndexHandler {

@GetMapping("/index")

public String index(){

System.out.println("index...");

return "index";

}

}

• HTML

Hello World

如果希望客户端可以直接访问 HTML 资源，将这些资源放置在 static 路径下即可，否则必须通过

Handler 的后台映射才可以访问静态资源。

 

Thymeleaf 常⽤语法

• 赋值、拼接

@GetMapping("/index2")

public String index2(Map map){

map.put("name","张三");

return "index";

}

• 条件判断：if/unless

th:if 表示条件成⽴时显示内容，th:unless 表示条件不成⽴时显示内容

@GetMapping("/if")

public String index3(Map map){

map.put("flag",true);

return "index";

}

• 循环

@GetMapping("/index")

public String index(Model model){

System.out.println("index...");

List list = new ArrayList<>();

list.add(new Student(1L,"张三",22));

list.add(new Student(2L,"李四",23));

list.add(new Student(3L,"王五",24));

model.addAttribute("list",list);

return "index";

}

index	count	学⽣ID	学⽣姓名	学⽣年龄

stat 是状态变量，属性：

• index 集合中元素的index（从0开始）
• count 集合中元素的count（从1开始）size 集合的⼤⼩
• current 当前迭代变量
• even/odd 当前迭代是否为偶数/奇数（从0开始计算）
• fifirst 当前迭代的元素是否是第⼀个
• last 当前迭代的元素是否是最后⼀个
• URL

Thymeleaf 对于 URL 的处理是通过 @{...} 进⾏处理，结合 th:href 、th:src

Hello World

跳转

跳转2

• 三元运算

@GetMapping("/eq")

public String eq(Model model){

model.addAttribute("age",30);

return "test";

}

• gt great than ⼤于
• ge great equal ⼤于等于
• eq equal 等于
• lt less than ⼩于
• le less equal ⼩于等于
• ne not equal 不等于
• switch

@GetMapping("/switch")

public String switchTest(Model model){

model.addAttribute("gender","⼥");

return "test";}

 

⼥

男

未知

• 基本对象
  • #ctx ：上下⽂对象
  • #vars ：上下⽂变量
  • #locale ：区域对象
  • #request ：HttpServletRequest 对象
  • #response ：HttpServletResponse 对象
  • #session ：HttpSession 对象
  • #servletContext ：ServletContext 对象

@GetMapping("/object")

public String object(HttpServletRequest request){

request.setAttribute("request","request对象");

request.getSession().setAttribute("session","session对象");

return "test";

}

 

• 内嵌对象

可以直接通过 # 访问。

1、dates：java.util.Date 的功能⽅法

2、calendars：java.util.Calendar 的功能⽅法

3、numbers：格式化数字

4、strings：java.lang.String 的功能⽅法

5、objects：Object 的功能⽅法

6、bools：对布尔求值的⽅法

7、arrays：操作数组的功能⽅法

8、lists：操作集合的功能⽅法

9、sets：操作集合的功能⽅法10、maps：操作集合的功能⽅法

10、maps：操作集合的功能⽅法

@GetMapping("/util")

public String util(Model model){

model.addAttribute("name","zhangsan");

model.addAttribute("users",new ArrayList<>());

model.addAttribute("count",22);

model.addAttribute("date",new Date());

return "test";

}

 

Spring Boot 数据校验

package com.vl.entity;

import lombok.Data;

import org.hibernate.validator.constraints.Length;

import javax.validation.constraints.Min;

import javax.validation.constraints.NotEmpty;

import javax.validation.constraints.NotNull;

@Data

public class User {

@NotNull(message = "id不能为空")

private Long id;

@NotEmpty(message = "姓名不能为空")

@Length(min = 2,message = "姓名⻓度不能⼩于2位")

private String name; @Min(value = 16,message = "年龄必须⼤于16岁")

private int age;

}

@GetMapping("/validator")

public void validatorUser(@Valid User user,BindingResult bindingResult){

System.out.println(user);

if(bindingResult.hasErrors()){

List list = bindingResult.getAllErrors();

for(ObjectError objectError:list){

System.out.println(objectError.getCode()+"-

"+objectError.getDefaultMessage());

}

}

}

Spring Boot 整合 JDBC

• pom.xml

org.springframework.boot

spring-boot-starter-jdbc

mysql

mysql-connector-java

8.0.11

• application.yml

server:

port: 9090

spring:

thymeleaf:

prefix: classpath:/templates/

suffix: .html

mode: HTML5

encoding: UTF-8

datasource:

url: jdbc:mysql://localhost:3306/test?

useUnicode=true&characterEncoding=UTF-8

username: root

password: root

driver-class-name: com.mysql.cj.jdbc.Driver

• User

package com.vl.entity;

import lombok.Data;

import org.hibernate.validator.constraints.Length;

import javax.validation.constraints.Min;

import javax.validation.constraints.NotEmpty;

import javax.validation.constraints.NotNull;

@Data

public class User {

@NotNull(message = "id不能为空")

private Long id;

@NotEmpty(message = "姓名不能为空")

@Length(min = 2,message = "姓名⻓度不能⼩于2位")

private String name;

@Min(value = 60,message = "成绩必须⼤于60分")

private double score;

}

• UserRepository

package com.southwind.repository;

import com.southwind.entity.User;

import java.util.List;

public interface UserRepository {

public List findAll();

public User findById(long id);

public void save(User user);

public void update(User user);

public void deleteById(long id);

}

• UserRepositoryImpl

package com.southwind.repository.impl;

import com.southwind.entity.User;

import com.southwind.repository.UserRepository;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.jdbc.core.BeanPropertyRowMapper;

import org.springframework.jdbc.core.JdbcTemplate;

import org.springframework.stereotype.Repository;

import java.util.List;

@Repository

public class UserRepositoryImpl implements UserRepository {

@Autowired

private JdbcTemplate jdbcTemplate;

@Override

public List findAll() {

return jdbcTemplate.query("select * from user",new

BeanPropertyRowMapper<>(User.class));

}

@Override

public User findById(long id) {

return jdbcTemplate.queryForObject("select * from user where id = ?",new

Object[]{id},new BeanPropertyRowMapper<>(User.class));

}

@Override

public void save(User user) {

jdbcTemplate.update("insert into user(name,score)values(?,?)",user.getName(),user.getScore());

}

@Override

public void update(User user) {

jdbcTemplate.update("update user set name = ?,score = ? where id =

?",user.getName(),user.getScore(),user.getId());

}

@Override

public void deleteById(long id) {

jdbcTemplate.update("delete from user where id = ?",id);

}

}

• Handler

package com.southwind.controller;

import com.southwind.entity.User;

import com.southwind.repository.UserRepository;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController

@RequestMapping("/user")

public class UserHandler {

@Autowired

private UserRepository userRepository;

@GetMapping("/findAll")

public List findAll(){

return userRepository.findAll();

}

@GetMapping("/findById/{id}")

public User findById(@PathVariable("id") long id){

return userRepository.findById(id);

}

@PostMapping("/save")

public void save(@RequestBody User user){

userRepository.save(user);

}

@PutMapping("/update") public void update(@RequestBody User user){

userRepository.update(user);

}

@DeleteMapping("/deleteById/{id}")

public void deleteById(@PathVariable("id") long id){

userRepository.deleteById(id);

}

}

Spring Boot 整合 MyBatis

 

• pom.xml

org.mybatis.spring.boot

mybatis-spring-boot-starter

1.3.1

 

• application.yml

server:

port: 9090

spring:

thymeleaf:

prefix: classpath:/templates/

suffix: .html

mode: HTML5

encoding: UTF-8

datasource:

url: jdbc:mysql://localhost:3306/test?

useUnicode=true&characterEncoding=UTF-8

username: root

password: root

driver-class-name: com.mysql.cj.jdbc.Driver

mybatis:

mapper-locations: classpath:/mapping/*.xml

type-aliases-package: com.val.entity

• UserRepository

package com.southwind.mapper;

import com.southwind.entity.User;import java.util.List;

public interface UserRepository {

public List findAll(int index,int limit);

public User findById(long id);

public void save(User user);

public void update(User user);

public void deleteById(long id);

public int count();

}

• UserRepository.xml

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

select * from user limit #{param1},#{param2}

select count(id) from user

select * from user where id = #{id}

insert into user(name,score) values(#{name},#{score})

update user set name = #{name},score = #{score} where id = #{id}

delete from user where id = #{id}

• User

package com.southwind.entity;

import lombok.Data;import org.hibernate.validator.constraints.Length;

import javax.validation.constraints.Min;

import javax.validation.constraints.NotEmpty;

import javax.validation.constraints.NotNull;

@Data

public class User {

@NotNull(message = "id不能为空")

private Long id;

@NotEmpty(message = "姓名不能为空")

@Length(min = 2,message = "姓名⻓度不能⼩于2位")

private String name;

@Min(value = 60,message = "成绩必须⼤于60分")

private double score;

}

• Handler

package com.southwind.controller;

import com.southwind.entity.User;

import com.southwind.mapper.UserRepository;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.*;

import org.springframework.web.servlet.ModelAndView;

@Controller

@RequestMapping("/mapper")

public class UserMapperHandler {

@Autowired

private UserRepository userRepository;

private int limit = 10;

@GetMapping("/findAll/{page}")

public ModelAndView findAll(@PathVariable("page") int page){

ModelAndView modelAndView = new ModelAndView();

int index = (page-1)*limit;

modelAndView.setViewName("show");

modelAndView.addObject("list",userRepository.findAll(index,limit));

modelAndView.addObject("page",page);

//计算总⻚数

int count = userRepository.count();

int pages = 0;

if(count%limit == 0){

pages = count/limit;

}else{

pages = count/limit+1; }

modelAndView.addObject("pages",pages);

return modelAndView;

}

@GetMapping("/deleteById/{id}")

public String deleteById(@PathVariable("id") long id){

userRepository.deleteById(id);

return "redirect:/mapper/findAll/1";

}

@GetMapping("/findById")

public ModelAndView findById(@RequestParam("id") long id){

ModelAndView modelAndView = new ModelAndView();

modelAndView.addObject("user",userRepository.findById(id));

modelAndView.setViewName("update");

return modelAndView;

}

@PostMapping("/update")

public String update(User user){

userRepository.update(user);

return "redirect:/mapper/findAll/1";

}

@PostMapping("/save")

public String save(User user){

userRepository.save(user);

return "redirect:/mapper/findAll/1";

}

@GetMapping("/redirect/{name}")

public String redirect(@PathVariable("name") String name){

return name;

}

}

• HTML

⽤户姓名：
⽤户成绩：

⽤户ID：

⽤户姓名：

⽤户成绩：

 

⽤户信息

⽤户ID	⽤户名	成绩	操作
			删除 修改

⾸⻚

上⼀⻚

/

下⼀⻚

尾⻚

添加⽤户