Spring Boot入門(五)：使用JDBC訪問MySql數據庫

時間  2019-12-12
標籤 spring boot 入門 使用 jdbc 訪問 mysql 數據庫 欄目 Spring 简体版
原文   原文鏈接

本系列博客記錄本身學習Spring Boot的歷程，如幫助到你，不勝榮幸，若有錯誤，歡迎指正！html

在程序開發的過程當中，操做數據庫是必不可少的部分，前面幾篇博客中，也一直未涉及到數據庫的操做，本篇博客java

就講解下在Spring Boot中如何使用JDBC操做數據庫。mysql

1.前期準備

假設你的機器已經安裝好了MySql，咱們先執行以下語句建立數據庫和表：git

CREATE DATABASE springbootdemo_db

create table book_list
(
  book_id       int auto_increment primary key,
  book_name     varchar(50) not null comment '書名',
  book_author   varchar(20) not null comment '做者',
  purchase_date date        not null comment '購買日期'
)
comment '書單';

2.修改pom文件

pom文件引入jdbc的starter pom和mysql的驅動，因後面要編寫控制器，所以也引入下阿里巴巴的fastjson：github

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.35</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.47</version>
</dependency>

3.配置數據源

在resources/application.yml中配置數據源：web

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/springbootdemo_db
    username: root
    password:

4.定義數據庫實體

定義數據庫實體Book：spring

package com.zwwhnly.springbootdemo.jdbc;

import java.util.Date;

public class Book {
    private Integer bookId;
    private String bookName;
    private String bookAuthor;
    private Date purchaseDate;

    public Integer getBookId() {
        return bookId;
    }

    public void setBookId(Integer bookId) {
        this.bookId = bookId;
    }

    public String getBookName() {
        return bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public String getBookAuthor() {
        return bookAuthor;
    }

    public void setBookAuthor(String bookAuthor) {
        this.bookAuthor = bookAuthor;
    }

    public Date getPurchaseDate() {
        return purchaseDate;
    }

    public void setPurchaseDate(Date purchaseDate) {
        this.purchaseDate = purchaseDate;
    }
}

5.編寫Dao層代碼

定義接口BookDao：sql

package com.zwwhnly.springbootdemo.jdbc;

import java.util.List;

public interface BookDao {
    int add(Book book);

    int update(Book book);

    int delete(Integer id);

    Book findBook(Integer id);

    List<Book> findBookList();
}

定義接口實現類BookDaoImpl：數據庫

package com.zwwhnly.springbootdemo.jdbc;

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 BookDaoImpl implements BookDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public int add(Book book) {
        return jdbcTemplate.update("INSERT INTO book_list values (NULL, ?, ?, ?);",
                book.getBookName(), book.getBookAuthor(), book.getPurchaseDate());
    }

    @Override
    public int update(Book book) {
        return jdbcTemplate.update("UPDATE book_list SET book_name=?,book_author=?,purchase_date=? WHERE book_id = ?;",
                new Object[]{book.getBookName(), book.getBookAuthor(), book.getPurchaseDate(), book.getBookId()});
    }

    @Override
    public int delete(Integer id) {
        return jdbcTemplate.update("DELETE FROM book_list where book_id = ?", id);
    }

    @Override
    public Book findBook(Integer id) {
        List<Book> list = jdbcTemplate.query("SELECT * FROM book_list where book_id = ?", new Object[]{id}, new BeanPropertyRowMapper<Book>(Book.class));
        if (null != list && list.size() > 0) {
            Book book = list.get(0);
            return book;
        } else {
            return null;
        }
    }

    @Override
    public List<Book> findBookList() {
        List<Book> list = jdbcTemplate.query("SELECT * FROM book_list", new Object[]{}, new BeanPropertyRowMapper<Book>(Book.class));
        return list;
    }
}

注意：實現類添加@Repository註解，以便 Spring Boot實現自動裝配。json

關於自動裝配的問題，能夠參考以前的博客Spring入門(二)：自動化裝配bean。

6.編寫Service層代碼

定義接口BookService：

package com.zwwhnly.springbootdemo.jdbc;

import java.util.List;

public interface BookService {
    int add(Book book);

    int update(Book book);

    int delete(Integer id);

    Book findBook(Integer id);

    List<Book> findBookList();
}

而後定義實現類BookServiceImpl：

package com.zwwhnly.springbootdemo.jdbc;

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

import java.util.List;

@Service("bookService")
public class BookServiceImpl implements BookService {
    @Autowired
    private BookDao bookDao;

    @Override
    public int add(Book book) {
        return this.bookDao.add(book);
    }

    @Override
    public int update(Book book) {
        return this.bookDao.update(book);
    }

    @Override
    public int delete(Integer id) {
        return this.bookDao.delete(id);
    }

    @Override
    public Book findBook(Integer id) {
        return this.bookDao.findBook(id);
    }

    @Override
    public List<Book> findBookList() {
        return this.bookDao.findBookList();
    }
}

注意：實現類添加@Service註解，以便 Spring Boot實現自動裝配。

7.編寫控制器驗證

最後新建控制器BookController,驗證下增刪改查是否成功：

package com.zwwhnly.springbootdemo.controller;

import com.alibaba.fastjson.JSONObject;
import com.zwwhnly.springbootdemo.jdbc.Book;
import com.zwwhnly.springbootdemo.jdbc.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.text.SimpleDateFormat;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping(value = "/jdbc/book")
public class BookController {
    @Autowired
    private BookService bookService;

    @RequestMapping(value = "getBookList", method = RequestMethod.GET)
    public Map<String, Object> getBookList() {
        List<Book> bookList = this.bookService.findBookList();
        Map<String, Object> param = new HashMap<>();
        param.put("total", bookList.size());
        param.put("rows", bookList);
        return param;
    }

    @RequestMapping(value = "/getBook/{bookId:\\d+}", method = RequestMethod.GET)
    public Book getBook(@PathVariable Integer bookId) {
        Book book = this.bookService.findBook(bookId);
        if (book == null) {
            throw new RuntimeException("查詢錯誤");
        }
        return book;
    }

    @RequestMapping(value = "add", method = RequestMethod.POST)
    public void add(@RequestBody JSONObject jsonObject) {
        String bookName = jsonObject.getString("bookName");
        String bookAuthor = jsonObject.getString("bookAuthor");
        String purchaseDate = jsonObject.getString("purchaseDate");

        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");

        try {
            Book book = new Book();
            book.setBookName(bookName);
            book.setBookAuthor(bookAuthor);
            book.setPurchaseDate(simpleDateFormat.parse(purchaseDate));
            this.bookService.add(book);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("新增錯誤");
        }
    }

    @RequestMapping(value = "/update/{bookId:\\d+}", method = RequestMethod.PUT)
    public void update(@PathVariable Integer bookId, @RequestBody JSONObject jsonObject) {
        Book book = this.bookService.findBook(bookId);
        String bookName = jsonObject.getString("bookName");
        String bookAuthor = jsonObject.getString("bookAuthor");
        String purchaseDate = jsonObject.getString("purchaseDate");
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        try {
            book.setBookName(bookName);
            book.setBookAuthor(bookAuthor);
            book.setPurchaseDate(simpleDateFormat.parse(purchaseDate));
            this.bookService.update(book);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("更新錯誤");
        }
    }

    @RequestMapping(value = "/delete/{bookId:\\d+}", method = RequestMethod.DELETE)
    public void delete(@PathVariable Integer bookId) {
        try {
            this.bookService.delete(bookId);
        } catch (Exception e) {
            throw new RuntimeException("刪除錯誤");
        }
    }
}

7.1驗證新增

由於新增是Post請求，所以這裏咱們使用下Postman工具：

調用完接口，發現數據庫新增數據成功。

7.2驗證更新

調用更新接口將剛剛新增數據的購買日期修改成2010-01-01：

調用完接口，發現數據庫更新數據成功。

7.3驗證獲取列表

在瀏覽器訪問http://localhost:8080/jdbc/book/getBookList，返回數據以下：

{
  "total": 2,
  "rows": [
    {
      "bookId": 1,
      "bookName": "平凡的世界",
      "bookAuthor": "路遙",
      "purchaseDate": "2009-12-31T16:00:00.000+0000"
    },
    {
      "bookId": 2,
      "bookName": "人生",
      "bookAuthor": "路遙",
      "purchaseDate": "2010-12-31T16:00:00.000+0000"
    }
  ]
}

觀察返回的數據，咱們發現2個問題：

  1. purchaseDate字段的值比數據庫中的少8個小時
  2. purchaseDate字段顯示不夠友好

出現緣由：Spring Boot中返回json格式默認使用jackson框架轉換，而jackson框架默認的時區是GMT(相比於中國是少了8小時)。

解決方案：

若是是全局統一修改，則修改resources/application.yml，添加以下配置：

spring:
  jackson:
      time-zone: GMT+8,
      date-format: yyyy-MM-dd HH:mm:ss

若是想單個修改，則修改下實體類：

import com.fasterxml.jackson.annotation.JsonFormat;

@JsonFormat(timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
private Date purchaseDate;

再次訪問http://localhost:8080/jdbc/book/getBookList，返回數據以下：

{
  "total": 2,
  "rows": [
    {
      "bookId": 1,
      "bookName": "平凡的世界",
      "bookAuthor": "路遙",
      "purchaseDate": "2010-01-01 00:00:00"
    },
    {
      "bookId": 2,
      "bookName": "人生",
      "bookAuthor": "路遙",
      "purchaseDate": "2011-01-01 00:00:00"
    }
  ]
}

7.4驗證獲取單個數據

在瀏覽器訪問http://localhost:8080/jdbc/book/getBook/1，返回以下數據：

{
  "bookId": 1,
  "bookName": "平凡的世界",
  "bookAuthor": "路遙",
  "purchaseDate": "2010-01-01 00:00:00"
}

7.5驗證刪除

調用刪除接口，將bookId爲2的數據刪除：

此時訪問http://localhost:8080/jdbc/book/getBookList，返回數據只有1條了：

{
  "total": 1,
  "rows": [
    {
      "bookId": 1,
      "bookName": "平凡的世界",
      "bookAuthor": "路遙",
      "purchaseDate": "2010-01-01 00:00:00"
    }
  ]
}

8.源碼地址

原文地址：Spring Boot入門(四)：開發Web Api接口經常使用註解總結

博客地址：http://www.zwwhnly.com

源碼地址：https://github.com/zwwhnly/springbootdemo.git

歡迎你們下載，有問題能夠多多交流。

9.參考連接

SpringBoot 返回json格式數據時間格式配置相差8個小時的時差問題

Spring boot Controller類返回Date時間少8小時

Spring Boot 揭祕與實戰（二） 數據存儲篇 - MySQL

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