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。



    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.southwind.entity;

import lombok.Data;

@Data
public class Student {
    private long id;
    private String name;
    private int age;
}

3、StudentRepository

package com.southwind.repository;

import com.southwind.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.southwind.repository.impl;

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

import com.southwind.entity.Student;
import com.southwind.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);
    }

    @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.southwind;

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
server:
  port: 8181
spring:
  mvc:
    view:
      prefix: /
      suffix: .jsp
  • 创建 Handler
package com.southwind.controller;

import com.southwind.entity.Student;
import com.southwind.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: southwind
  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: southwind
  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


    

        ID:

        name:

        age:

        
    




<%--
  Created by IntelliJ IDEA.
  User: southwind
  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


    

        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

image-20220117095749560

static可以访问

image-20220117103619941

server:
  port: 9090
spring:
  thymeleaf:
    prefix: classpath:/templates/
    suffix: .html
    mode: HTML5
    encoding: UTF-8
  • Handler
package com.southwind.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



    
    Title


    
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）

  • 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

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

@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.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 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.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.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.southwind.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
<?xml version="1.0" encoding="UTF-8" ?>
        


    

    

    

    
        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.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




    
    Title


    

        用户姓名：

        用户成绩：

        
    








    
    Title


    

        用户ID：

        用户姓名：

        用户成绩：

        
    








    
    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>


    
用户信息

    

        

            用户ID
            用户名
            成绩
            操作
        

        

            
            
            
            
                删除
                修改
            
        

    

    首页
    
    /
    
    尾页

    添加用户

参考文章

Spring Boot从入门到实战

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