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。
<!-- 继承⽗包 --><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.0.7.RELEASE</version></parent><dependencies><!-- web启动jar --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.6</version><scope>provided</scope></dependency></dependencies>
2、创建 Student 实体类
package com.val.entity;import lombok.Data;@Datapublic 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<Student> 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;@Repositorypublic class StudentRepositoryImpl implements StudentRepository {private static Map<Long,Student> 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)); }@Overridepublic Collection<Student> findAll() {return studentMap.values();}@Overridepublic Student findById(long id) {return studentMap.get(id);}@Overridepublic void saveOrUpdate(Student student) {studentMap.put(student.getId(),student);}@Overridepublic 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 {@Autowiredprivate StudentRepository studentRepository;@GetMapping("/findAll")public Collection<Student> 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;@SpringBootApplicationpublic 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
<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.0.7.RELEASE</version></parent><dependencies><!-- web --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!-- 整合JSP --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-tomcat</artifactId></dependency><dependency><groupId>org.apache.tomcat.embed</groupId><artifactId>tomcat-embed-jasper</artifactId></dependency><!-- JSTL --><dependency><groupId>jstl</groupId><artifactId>jstl</artifactId><version>1.2</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.6</version><scope>provided</scope></dependency></dependencies>
- 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 {@Autowiredprivate 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: 2020-06-12Time: 12:02To 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" %><html><head><title>Title</title></head><body><h1>学⽣信息</h1><table><tr><th>学⽣编号</th><th>学⽣姓名</th><th>学⽣年龄</th><th>操作</th></tr><c:forEach items="${list}" var="student"><tr><td>${student.id}</td><td>${student.name}</td><td>${student.age}</td><td><a href="/hello/findById/${student.id}">修改</a><a href="/hello/deleteById/${student.id}">删除</a></td></tr></c:forEach></table><a href="/save.jsp">添加学⽣</a></body></html>
<%--Created by IntelliJ IDEA.Spring Boot HTMLSpring Boot 可以结合 Thymeleaf 模版来整合 HTML,使⽤原⽣的 HTML 作为视图。User: valDate: 2020-06-12Time: 12:09To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head><title>Title</title></head><body><form action="/hello/save" method="post">ID:<input type="text" name="id"/><br/>name:<input type="text" name="name"/><br/>age:<input type="text" name="age"/><br/><input type="submit" value="提交"/></form></body></html>
<%--Created by IntelliJ IDEA.User: valDate: 2020-06-12Time: 12:09To change this template use File | Settings | File Templates.--%><%@ page contentType="text/html;charset=UTF-8" language="java" %><html><head><title>Title</title></head><body><form action="/hello/update" method="post">ID:<input type="text" name="id" value="${student.id}" readonly/><br/>name:<input type="text" name="name" value="${student.name}"/><br/>age:<input type="text" name="age" value="${student.age}"/><br/><input type="submit" value="提交"/></form></body></html>
Spring Boot HTML
Spring Boot 可以结合 Thymeleaf 模版来整合 HTML,使⽤原⽣的 HTML 作为视图。
Thymeleaf 模版是⾯向 Web 和独⽴环境的 Java 模版引擎,能够处理 HTML、XML、JavaScript、CSS
等。
<p th:text="${message}"></p>
- pom.xml
<!-- 继承⽗包 --><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.0.7.RELEASE</version></parent><dependencies><!-- web启动jar --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.6</version><scope>provided</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-thymeleaf</artifactId></dependency></dependencies>
- appliction.yml
server:port: 9090spring:thymeleaf:prefix: classpath:/templates/suffix: .htmlmode: HTML5encoding: 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
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><h1>Hello World</h1></body></html>
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<String,String> map){map.put("name","张三");return "index";}
<p th:text="${name}"></p><p th:text="'学⽣姓名是'+${name}+2"></p><p th:text="|学⽣姓名是,${name}|"></p>
- 条件判断:if/unless
th:if 表示条件成⽴时显示内容,th:unless 表示条件不成⽴时显示内容
@GetMapping("/if")public String index3(Map<String,Boolean> map){map.put("flag",true);return "index";}
<p th:if="${flag == true}" th:text="if判断成⽴"></p><p th:unless="${flag != true}" th:text="unless判断成⽴"></p>
- 循环
@GetMapping("/index")public String index(Model model){System.out.println("index...");List<Student> list = new ArrayList<>();list.add(new Student(1L,"张三",22));list.add(new Student(2L,"李四",23));list.add(new Student(3L,"王五",24));model.addAttribute("list",list);return "index";}<table><tr><th>index</th><th>count</th><th>学⽣ID</th><th>学⽣姓名</th><th>学⽣年龄</th></tr><tr th:each="student,stat:${list}" th:style="'backgroundcolor:'+@{${stat.odd}?'#F2F2F2'}"><td th:text="${stat.index}"></td><td th:text="${stat.count}"></td><td th:text="${student.id}"></td><td th:text="${student.name}"></td><td th:text="${student.age}"></td></tr></table>
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
<h1>Hello World</h1>
<a th:href="@{http://www.baidu.com}">跳转</a>
<a th:href="@{http://localhost:9090/index/url/{na}(na=${name})}">跳转2</a>
<img th:src="${src}">
<div th:style="'background:url('+ @{${src}} +');'">
<br/>
<br/>
<br/>
</div>
- 三元运算
@GetMapping("/eq")public String eq(Model model){model.addAttribute("age",30);return "test";}<input th:value="${age gt 30?'中年':'⻘年'}"/>
- 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";}
<div th:switch="${gender}"><p th:case="⼥">⼥</p><p th:case="男">男</p><p th:case="*">未知</p></div>
- 基本对象
- #ctx :上下⽂对象
- #vars :上下⽂变量
- #locale :区域对象
- #request :HttpServletRequest 对象
- #response :HttpServletResponse 对象
- #session :HttpSession 对象
- #servletContext :ServletContext 对象
@GetMapping("/object")public String object(HttpServletRequest request){request.setAttribute("request","request对象");request.getSession().setAttribute("session","session对象");return "test";}
<p th:text="${#request.getAttribute('request')}"></p><p th:text="${#session.getAttribute('session')}"></p><p th:text="${#locale.country}"></p>
- 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";}
<!-- 格式化时间 --><p th:text="${#dates.format(date,'yyyy-MM-dd HH:mm:sss')}"></p><!-- 创建当前时间,精确到天 --><p th:text="${#dates.createToday()}"></p><!-- 创建当前时间,精确到秒 --><p th:text="${#dates.createNow()}"></p><!-- 判断是否为空 --><p th:text="${#strings.isEmpty(name)}"></p><!-- 判断List是否为空 --><p th:text="${#lists.isEmpty(users)}"></p><!-- 输出字符串⻓度 --><p th:text="${#strings.length(name)}"></p><!-- 拼接字符串 --><p th:text="${#strings.concat(name,name,name)}"></p><!-- 创建⾃定义字符串 --><p th:text="${#strings.randomAlphanumeric(count)}"></p>
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;@Datapublic 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<ObjectError> list = bindingResult.getAllErrors();for(ObjectError objectError:list){System.out.println(objectError.getCode()+"-"+objectError.getDefaultMessage());}}}
Spring Boot 整合 JDBC
- pom.xml
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.11</version></dependency>
- application.yml
server:port: 9090spring:thymeleaf:prefix: classpath:/templates/suffix: .htmlmode: HTML5encoding: UTF-8datasource:url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8username: rootpassword: rootdriver-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;@Datapublic 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<User> 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<User> 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 {@Autowiredprivate UserRepository userRepository;@GetMapping("/findAll")public List<User> 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
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.1</version>
</dependency>
- application.yml
server:port: 9090spring:thymeleaf:prefix: classpath:/templates/suffix: .htmlmode: HTML5encoding: UTF-8datasource:url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8username: rootpassword: rootdriver-class-name: com.mysql.cj.jdbc.Drivermybatis:mapper-locations: classpath:/mapping/*.xmltype-aliases-package: com.val.entity
- UserRepository
package com.southwind.mapper;import com.southwind.entity.User;import java.util.List;public interface UserRepository {public List<User> 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
<?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.southwind.mapper.UserRepository"><select id="findAll" resultType="User">select * from user limit #{param1},#{param2}</select><select id="count" resultType="int">select count(id) from user</select><select id="findById" parameterType="long" resultType="User">select * from user where id = #{id}</select><insert id="save" parameterType="User">insert into user(name,score) values(#{name},#{score})</insert><update id="update" parameterType="User">update user set name = #{name},score = #{score} where id = #{id}</update><delete id="deleteById" parameterType="long">delete from user where id = #{id}</delete></mapper>
- 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;@Datapublic 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 {@Autowiredprivate 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
<!DOCTYPE html><html xmlns:th="http://www.thymeleaf.org"><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><form action="/mapper/save" method="post">⽤户姓名:<input type="text" name="name" /><br/> ⽤户成绩:<input type="text" name="score" /><br/><input type="submit" value="提交"/></form></body></html><!DOCTYPE html><html xmlns:th="http://www.thymeleaf.org"><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><form action="/mapper/update" method="post">⽤户ID:<input type="text" name="id" th:value="${user.id}" readonly/><br/>⽤户姓名:<input type="text" name="name" th:value="${user.name}" /><br/>⽤户成绩:<input type="text" name="score" th:value="${user.score}" /><br/><input type="submit" value="提交"/></form></body></html>
<!DOCTYPE html><html xmlns:th="http://www.thymeleaf.org"><html lang="en"><head><meta charset="UTF-8"><title>Title</title><script type="text/javascript" th:src="@{/jquery-3.3.1.min.js}"></script><script type="text/javascript">$(function(){$("#first").click(function(){var page = $("#page").text();page = parseInt(page);if(page == 1){return false;}window.location.href="/mapper/findAll/1";});$("#previous").click(function(){var page = $("#page").text();page = parseInt(page); if(page == 1){return false;}page = page-1;window.location.href="/mapper/findAll/"+page;});$("#next").click(function(){var page = $("#page").text();var pages = $("#pages").text();if(page == pages){return false;}page = parseInt(page);page = page+1;window.location.href="/mapper/findAll/"+page;});$("#last").click(function(){var page = $("#page").text();var pages = $("#pages").text();if(page == pages){return false;}window.location.href="/mapper/findAll/"+pages;});});</script></head><body><h1>⽤户信息</h1><table><tr><th>⽤户ID</th><th>⽤户名</th><th>成绩</th><th>操作</th></tr><tr th:each="user:${list}"><td th:text="${user.id}"></td><td th:text="${user.name}"></td><td th:text="${user.score}"></td><td><a th:href="@{/mapper/deleteById/{id}(id=${user.id})}">删除</a><a th:href="@{/mapper/findById(id=${user.id})}">修改</a></td></tr></table><a id="first" href="javascript:void(0)">⾸⻚</a><a id="previous" href="javascript:void(0)">上⼀⻚</a><span id="page" th:text="${page}"></span>/<span id="pages"th:text="${pages}"></span><a id="next" href="javascript:void(0)">下⼀⻚</a><a id="last" href="javascript:void(0)">尾⻚</a><br/><a href="/mapper/redirect/save">添加⽤户</a></body></html>
人们容易原谅别人的错误,却很难原谅别人的正确!