Spring Boot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 Spring Cloud 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。
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.0.7.RELEASEversion>
parent>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.6version>
<scope>providedscope>
dependency>
dependencies>
2、创建 Student 实体类
package com.tinchi.entity;
import lombok.Data;
@Data
public class Student {
private long id;
private String name;
private int age;
}
3、StudentRepository
package com.tinchi.repository;
import com.tinchi.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.tinchi.repository.impl;
import com.tinchi.entity.Student;
import com.tinchi.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<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));
}
@Override
public Collection<Student> 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.tinchi.controller;
import com.tinchi.entity.Student;
import com.tinchi.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<Student> findAll(){
return studentRepository.findAll();
}
@GetMapping("/findById/{id}")
public Student findById(@PathVariable("id") long id){
return studentRepository.findById(id);
}
@PostMapping("/save")
public void save(@RequestBody Student student){
studentRepository.saveOrUpdate(student);
}
@PutMapping("/update")
public void update(@RequestBody Student student){
studentRepository.saveOrUpdate(student);
}
@DeleteMapping("/deleteById/{id}")
public void deleteById(@PathVariable("id") long id){
studentRepository.deleteById(id);
}
}
6、application.yml
server:
port: 9090
7、启动类
package com.tinchi;
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
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.0.7.RELEASEversion>
parent>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-tomcatartifactId>
dependency>
<dependency>
<groupId>org.apache.tomcat.embedgroupId>
<artifactId>tomcat-embed-jasperartifactId>
dependency>
<dependency>
<groupId>jstlgroupId>
<artifactId>jstlartifactId>
<version>1.2version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.6version>
<scope>providedscope>
dependency>
dependencies>
- 创建配置文件 application.yml
server:
port: 8181
spring:
mvc:
view:
prefix: /
suffix: .jsp
- 创建 Handler
package com.tinchi.controller;
import com.tinchi.entity.Student;
import com.tinchi.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.
User: tinchi
Date: 2019-03-21
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" %>
Title
学生信息
学生编号
学生姓名
学生年龄
操作
${student.id}
${student.name}
${student.age}
修改
删除
添加学生
<%--
Created by IntelliJ IDEA.
User: tinchi
Date: 2019-03-21
Time: 12:09
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
Title
<%--
Created by IntelliJ IDEA.
User: tinchi
Date: 2019-03-21
Time: 12:09
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
Title
Spring Boot HTML
Spring Boot 可以结合 Thymeleaf 模版来整合 HTML，使用原生的 HTML 作为视图。
Thymeleaf 模版是面向 Web 和独立环境的 Java 模版引擎，能够处理 HTML、XML、JavaScript、CSS 等。
- pom.xml
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.0.7.RELEASEversion>
parent>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.6version>
<scope>providedscope>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-thymeleafartifactId>
dependency>
dependencies>
- appliction.yml
server:
port: 9090
spring:
thymeleaf:
prefix: classpath:/templates/
suffix: .html
mode: HTML5
encoding: UTF-8
- Handler
package com.tinchi.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
@RequestMapping("/index")
public class IndexHandler {
@GetMapping("/index")
public String index(){
System.out.println("index...");
return "index";
}
}
- HTML
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
head>
<body>
<h1>Hello Worldh1>
body>
html>
如果希望客户端可以直接访问 HTML 资源，将这些资源放置在 static 路径下即可，否则必须通过 Handler 的后台映射才可以访问静态资源。
Thymeleaf 常用语法
- 赋值、拼接
@GetMapping("/index2")
public String index2(Map<String,String> map){
map.put("name","张三");
return "index";
}
<p th:text="${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>indexth>
<th>countth>
<th>学生IDth>
<th>学生姓名th>
<th>学生年龄th>
tr>
<tr th:each="student,stat:${list}" th:style="'background-color:'+@{${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="${student.age}">td>
tr>
table>
stat 是状态变量，属性：
-
index 集合中元素的index（从0开始）
-
count 集合中元素的count（从1开始）
-
size 集合的大小
-
current 当前迭代变量
-
even/odd 当前迭代是否为偶数/奇数（从0开始计算）
-
first 当前迭代的元素是否是第一个
-
last 当前迭代的元素是否是最后一个
-
URL
Thymeleaf 对于 URL 的处理是通过 @{...} 进行处理，结合 th:href 、th:src
<h1>Hello Worldh1>
<a th:href="@{http://www.baidu.com}">跳转a>
<a th:href="@{http://localhost:9090/index/url/{na}(na=${name})}">跳转2a>
<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="${age gt 30?'中年':'青年'}"/>
-
gt great than 大于
-
ge great equal 大于等于
-
eq equal 等于
-
lt less than 小于
-
le less equal 小于等于
-
ne not equal 不等于
-
switch
@GetMapping("/switch")
public String switchTest(Model model){
model.addAttribute("gender","女");
return "test";
}
<div th:switch="${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="${#locale.country}">p>
- 内嵌对象
可以直接通过 # 访问。
1、dates：java.util.Date 的功能方法
2、calendars：java.util.Calendar 的功能方法
3、numbers：格式化数字
4、strings：java.lang.String 的功能方法
5、objects：Object 的功能方法
6、bools：对布尔求值的方法
7、arrays：操作数组的功能方法
8、lists：操作集合的功能方法
9、sets：操作集合的功能方法
10、maps：操作集合的功能方法
@GetMapping("/util")
public String util(Model model){
model.addAttribute("name","zhangsan");
model.addAttribute("users",new ArrayList<>());
model.addAttribute("count",22);
model.addAttribute("date",new Date());
return "test";
}
<p th:text="${#dates.format(date,'yyyy-MM-dd HH:mm:sss')}">p>
<p th:text="${#dates.createToday()}">p>
<p th:text="${#dates.createNow()}">p>
<p th:text="${#strings.isEmpty(name)}">p>
<p th:text="${#lists.isEmpty(users)}">p>
<p th:text="${#strings.length(name)}">p>
<p th:text="${#strings.concat(name,name,name)}">p>
<p th:text="${#strings.randomAlphanumeric(count)}">p>
Spring Boot 数据校验
package com.tinchi.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 = "姓名长度不能小于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.bootgroupId>
<artifactId>spring-boot-starter-jdbcartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>8.0.11version>
dependency>
- 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.tinchi.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 = "姓名长度不能小于2位")
private String name;
@Min(value = 60,message = "成绩必须大于60分")
private double score;
}
- UserRepository
package com.tinchi.repository;
import com.tinchi.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.tinchi.repository.impl;
import com.tinchi.entity.User;
import com.tinchi.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.tinchi.controller;
import com.tinchi.entity.User;
import com.tinchi.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<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.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>1.3.1version>
dependency>
- 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.tinchi.entity
- UserRepository
package com.tinchi.mapper;
import com.tinchi.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
<mapper namespace="com.tinchi.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.tinchi.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 = "姓名长度不能小于2位")
private String name;
@Min(value = 60,message = "成绩必须大于60分")
private double score;
}
- Handler
package com.tinchi.controller;
import com.tinchi.entity.User;
import com.tinchi.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);
//计算总页数
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
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
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>
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
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>
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Titletitle>
<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 = $("#pages").text();
if(page == pages){
return false;
}
window.location.href="/mapper/findAll/"+pages;
});
});
script>
head>
<body>
<h1>用户信息h1>
<table>
<tr>
<th>用户IDth>
<th>用户名th>
<th>成绩th>
<th>操作th>
tr>
<tr th:each="user:${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=${user.id})}">修改a>
td>
tr>
table>
<a id="first" href="javascript:void(0)">首页a>
<a id="previous" href="javascript:void(0)">上一页a>
<span id="page" th:text="${page}">span>/<span id="pages" th:text="${pages}">span>
<a id="next" href="javascript:void(0)">下一页a>
<a id="last" href="javascript:void(0)">尾页a><br/>
<a href="/mapper/redirect/save">添加用户a>
body>
html>