springboot使用入门1
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第一个springboot项目
使用eclipse和gradle构建第一个springboot项目。
1环境搭建
Java生态体系中有三大构建工具:Ant、Maven和Gradle。Ant几乎销声匿迹,Maven由于较为不灵活的配置也渐渐被遗忘,而由于Gradle是基于Ant和Maven的一个优化版本,变得如日中天。
1、安装gradle:
第1步:获取gradle
官网下载gradle: https://gradle.org/releases/ //我下载的是v6.4
第2步:解压
解压到如下目录:F:\\qianduan\\gradle-6.4.1
第3步:配置环境变量
在系统变量中添加:
变量名:GRADLE_HOME
变量值:F:\\qianduan\\gradle-6.4.1
path中缀加:%GRADLE_HOME%\\bin
测试:启动cmd命令行
输入gradle或gradle –v
输出gradle的相关版本等信息,说明gradle配置成功。
2 创建gradle项目
1、eclipse安装插件
通过eclipse创建gradle项目: //我的eclipse自带了gradle插件。
1:安装gradle插件
http://download.eclipse.org/buildship/updates/e46/reases/2.x
help à install new softwareà输入上述地址,安装.
2:eclipse配置gradle
window-》preference—》gradle,选择自己本机安装的gradle
local installation directory:F:\\qianduan\\gradle-6.4.1
gradle user home:C:\\Users\\he\\.gradle
2、创建springboot项目
通过Spring Inutializr初始化
1:生成: https://start.spring.io/
2:通过指令编译-运行(方法1)
从命令行进入到项目的根目录F:\\qianduan\\wordspace\\hello
执行gradle build
运行:生成一个build目录,进去找到jar文件
java –jar build/libs/….jar //运行我们的项目
如果想结束项目,直接ctrl+c即可停止。
3:在eclipse中运行(方法2)
导入:打开eclipse,导入gradle项目,选中项目导入。
更新依赖:右键项目名—》gradle—》refresh gradle project
编译运行:右键Application.java—》run as—》java application
测试:打开google浏览器:输入localhost:8080 会出现一个错误页面
到此,springboot项目运行成功。
项目目录简介:
resourses:放静态资源
/static:放js、css
/templates 默认放页面的路径
/application.properties:配置页面路径、访问数据库信息
src :存放代码
build.gradle:类似于maven的pom.xml
3 核心代码
目标:实现用户管理的增删改查功能,学会使用springboot开发项目。
配置文件
mysq中创建user表: //现在mysql数据库中创建user表
user表:
id:int
name:varchar(255)
email:varchar(255)
参考sql代码:
create table user(
id int primary key,
name varchar(255),
email varchar(255) )
build.gradle代码如下:
//本身需要的插件
plugins {
id \'org.springframework.boot\' version \'2.3.0.RELEASE\'
id \'io.spring.dependency-management\' version \'1.0.9.RELEASE\'
id \'java\'
}
group = \'com.scitc\'
version = \'0.0.1-SNAPSHOT\'
sourceCompatibility = \'1.8\'
//指定仓库
repositories {
//mavenCentral()
mavenLocal()
maven{
url \'http://maven.aliyun.com/nexus/content/groups/public/\'
}
}
//依赖
dependencies {
implementation \'org.springframework.boot:spring-boot-starter-web\'
testImplementation(\'org.springframework.boot:spring-boot-starter-test\') {
exclude group: \'org.junit.vintage\', module: \'junit-vintage-engine\'
}
compile(\'org.springframework.boot:spring-boot-starter-thymeleaf\')
//spring data jpa的依赖
compile(\'org.springframework.boot:spring-boot-starter-data-jpa\')
//mysql连接驱动的依赖
compile(\'mysql:mysql-connector-java:6.0.5\')
//添加jquery依赖
compile group: \'org.webjars.bower\', name: \'jquery\', version: \'3.3.0\'
//添加bootstrap依赖
compile group: \'org.webjars\', name: \'bootstrap\', version: \'4.1.0\'
}
test {
useJUnitPlatform()
}
application.properties
# 这个是配置模板路径的,默认就是templates,可不用配置
#spring.thymeleaf.prefix=classpath:/templates/
# 这个可以不配置,检查模板位置
#spring.thymeleaf.check-template-location=true
spring.thymeleaf.suffix=.html
spring.thymeleaf.content-type=text/html
spring.thymeleaf.encoding=UTF-8
#热部署静态文件
spring.thymeleaf.cache=false
#使用html5
spring.thymeleaf.mode=HTML5
#DataSource
spring.datasource.url=jdbc:mysql://localhost/blog?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=admin
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#jpa
spring.jpa.show-sql = true
#spring.jpa.hibernate.ddl-auto=create-drop
domain层
User.java
package com.scitc.mytest.domain;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.xml.bind.annotation.XmlRootElement;
@Entity
@XmlRootElement //MediaType 转为 XML
@Table
public class User implements Serializable{
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;//实体唯一的标识
@Column(nullable = false)
private String name;
@Column(nullable = false)
private String email;
public User() {
}
public User(Long id,String name,String email) {
this.id = id;
this.name = name;
this.email = email;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public String toString() {
return String.format("User[id=%d, name=\'%s\', age=\'%d\']",
id, name, email);
}
}
UserRepository层
接口UserRepository.java
package com.scitc.mytest.repository;
import org.springframework.data.repository.CrudRepository;
import com.scitc.mytest.domain.User;
public interface UserRepository extends CrudRepository<User, Long> {
}
controller层
UserController.java
package com.scitc.mytest.controller;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ui.Model;
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.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;
import com.scitc.mytest.domain.User;
import com.scitc.mytest.repository.UserRepository;
@RestController
@RequestMapping("/users")
public class UserController {
@Autowired
private UserRepository userRepository;
/*
* 从用户仓库中获取用户列表
* */
private List<User> getUserlist(){
List<User> users = new ArrayList<>();
for(User user : userRepository.findAll()) {
users.add(user);
}
return users;
}
/**
* 查询所有用户,数据封装到模型中,返回视图模型对象
* @param model
* */
//get方法获取用户列表
@GetMapping
private ModelAndView list(Model model) {
model.addAttribute("userList", getUserlist());
model.addAttribute("title", "用户管理");
return new ModelAndView("users/list","userModel",model);
}
/**
* 根据id查询用户详细信息
*/
@GetMapping("{id}")
public ModelAndView view(@PathVariable("id") Long id,Model model){
Optional<User> user = userRepository.findById(id);
model.addAttribute("user", user.get());
model.addAttribute("title", "查看用户");
return new ModelAndView("users/view","userModel",model);
}
/**
*修改页面
*获取表单页面 ,自动把表单的数据填充到new User对象中
*userModel:是视图模型的名字,在页面可以获取到
*/
@GetMapping("/form")
public ModelAndView createForm(Model model){
model.addAttribute("user", new User());
model.addAttribute("title", "查看用户");
return new ModelAndView("users/form","userModel",model);
}
/**
* 新建用户
* @param user
* @param result
* @param redirect
* @return
* 根节点就是users,所以下面注解映射的路径不用填
*/
@PostMapping
public ModelAndView create(User user) {
user = userRepository.save(user);
return new ModelAndView("redirect:/users");
}
/**
* 删除用户
* @param id
* @return
*/
@GetMapping(value = "delete/{id}")
public ModelAndView delete(@PathVariable("id") Long id, Model model) {
userRepository.deleteById(id);;
model.addAttribute("userList", getUserlist());
model.addAttribute("title", "删除用户");
return new ModelAndView("redirect:/users");
//return new ModelAndView("users/list", "userModel", model);
}
/**
* 修改用户
* @param user
* @return
*/
@GetMapping(value = "modify/{id}")
public ModelAndView modifyForm(@PathVariable("id") Long id, Model model) {
Optional<User> user = userRepository.findById(id);
model.addAttribute("user", user.get());
model.addAttribute("title", "修改用户");
return new ModelAndView("users/form", "userModel", model);
}
}
页面
templates/fragments下:
header.html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout">
<head>
<meta charset="UTF-8">
<title>Thymeleaf in action</title>
</head>
<body>
<div th:fragment="header">
<h1>Thymeleaf in action</h1>
<a href="/users" th:href="@{~/users}">首页</a>
</div>
</body>
</html>
footer.html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout">
<head>
<meta charset="UTF-8">
<title>Thymeleaf in action</title>
</head>
<body>
<div th:fragment="footer">
<a href="#">欢迎来到我的主页!</a></div>
</body>
</html>
templates/users下:
list.html-显示用户页面
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout">
<head>
<meta charset="UTF-8">
<title th:text="${userModel.title}">welcome</title>
</head>
<body>
<div th:replace="fragments/header::header"></div>
<h3 th:text="${userModel.title}">Welcome to waylau.com</h3>
<table border="1">
<thead>
<tr>
<td>ID</td>
<td>name</td>
<td>email</td>
</tr>
</thead>
<tr th:if="${userModel.userList.size()} eq 0">
<td colspan="3">没有用户信息!!</td>
</tr>
<tr th:each="user:${userModel.userList}">
<td th:text="${user.id}">id</td>
<td th:text="${user.email}">email</td>
<td><a href="view.html" th:href="@{\'/users/\' + ${user.id}}"
th:text="${user.name}">he</a></td>
</tr>
</table>
<div th:replace="fragments/footer::footer"></div>
</body>
</html>
view.html-展示单个用户信息
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout">
<head>
<meta charset="UTF-8">
<title th:text="${userModel.title}">users : View</title>
</head>
<body>
<div th:replace="fragments/header::header"></div>
<h3 th:text="${userModel.title}">Welcome to waylau.com</h3>
<div>
<a href="/users">返回主页</a>
</div>
<div>
<p><strong>ID:</strong><span id="id" th:text="${userModel.user.id}">123</span></p>
<p><strong>Name:</strong><span id="name" th:text="${userModel.user.name}">he</span></p>
<p><strong>Email:</strong><span id="age" th:text="${userModel.user.email}">30</span></p>
</div>
<div>
<a th:href="@{\'/users/delete/\'+${userModel.user.id}}">删除</a>
<a th:href="@{\'/users/modify/\'+${userModel.user.id}}">修改</a>
</div>
<div th:replace="fragments/footer::footer"></div>
</body>
</html>
form.html-修改用户页面
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout">
<head>
<meta charset="UTF-8">
<title>修改页面</title>
</head>
<body>
<div th:replace="fragments/header::header"></div>
<h3 th:text="${userModel.title}">Welcome to waylau.com</h3>
<form action="/users" th:action="@{/users}" method="POST" th:object="${userModel.user}">
<input type="hidden" name="id" th:value="*{id}"> 名称:<br> <!-- eq th:value="${userModel.user.id}" -->
<input type="text" name="name" th:value="*{name}"> <br>
邮箱:<br> <input type="text" name="email" th:value="*{email}">
<input type="submit" value="提交">
</form>
<div th:replace="fragments/footer::footer"></div>
</body>
</html>
附件
mavenCentral寻找依赖插件
参考文献:
https://www.cnblogs.com/woms/p/7040771.html //gradle配置文件解析
https://www.cnblogs.com/ldy-blogs/p/8550406.html //常用注解
https://blog.csdn.net/yan88888888888888888/article/details/83652136 //自定义查询
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