1、什么是 JdbcTemplate
Spring 框架对 JDBC 进行封装,使用 JdbcTemplate 方便实现对数据库操作
2、前提准备
2.1 在项目中引入对应的jar包
官网下载jar包、然后加入的项目中(不知如何将jar包导入、可在我博客搜索查看、此处不在赘述)
2.2 在xml文件配置数据库连接池
友情提示:注意数据库的url以及登录名和账号。这里可以读取外部文件进行配置、前几篇博客有介绍使用。
<!-- 数据库连接池 -->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
destroy-method="close">
<property name="url" value="jdbc:mysql://localhost:3306/user_db" />
<property name="username" value="root" />
<property name="password" value="root" />
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
</bean>
2.3 配置 JdbcTemplate 对象,注入 DataSource
<!--jdbcTemplate对象-->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<!--注入dataSource-->
<property name="dataSource" ref="dataSource"></property>
</bean>
2.4 创建 service 类,创建 dao 类,在 dao 注入 jdbcTemplate 对象
这里使用注解开发
<!--开启组件扫描-->
<context:component-scan base-package="com.zyz"></context:component-scan>
/**
* @author Lenovo
* @version 1.0
* @data 2022/10/23 15:53
*/
@Service
public class BookService {
/**
* 注入dao
*/
@Autowired
private BookDao bookDao;
}
/**
* @author Lenovo
* @version 1.0
* @data 2022/10/23 15:53
*/
@Repository
public class BookDaoImpl implements BookDao{
/**
* 注入jdbcTemplate
*/
@Autowired
private JdbcTemplate jdbcTemplate;
}
2.5 数据库设计
2.6 创建实体类
package com.zyz.spring5.entity;
/**
* @author Lenovo
* @version 1.0
* @data 2022/10/23 16:10
*/
public class Book {
private int book_id;
private String book_name;
private String isSale;
public int getBook_id() {
return book_id;
}
public void setBook_id(int book_id) {
this.book_id = book_id;
}
public String getBook_name() {
return book_name;
}
public void setBook_name(String book_name) {
this.book_name = book_name;
}
public String getIsSale() {
return isSale;
}
public void setIsSale(String isSale) {
this.isSale = isSale;
}
@Override
public String toString() {
return "Book{" +
"book_id=" + book_id +
", book_name='" + book_name + '\'' +
", isSale='" + isSale + '\'' +
'}';
}
}
3、项目中的实际案例
3.1 项目结构
3.2 jdbcTemplate操作数据库 (添加操作)
这里只给出核心部分。具体代码在文章末尾给出。基本思路,dao中定义接口、daoImpl用来实现接口。service中进行调用
(1)在 dao 进行数据库添加操作
(2)调用 JdbcTemplate 对象里面 update 方法实现添加操作
@Override
public void addBook(Book book) {
//1、创建sql语句
String sql = "insert into t_book values(?,?,?)";
//2、调用方法
Object [] args ={book.getBook_id(),book.getBook_name(),book.getIsSale()};
int update = jdbcTemplate.update(sql,args);
System.out.println(update);
}
测试
@Test
public void testJdbcTemplate(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
Book book = new Book();
book.setBook_id(1);
book.setBook_name("Java");
book.setIsSale("出售");
bookService.addBook(book);
}
测试结果
3.2 修改操作
核心部分
这里sql的更新顺序要和参数的顺序保持一致
@Override
public void updateBook(Book book) {
//1、创建sql语句
String sql = "update t_book set book_name=?,isSale=? where book_id=?";
//2、调用方法
Object [] args ={book.getBook_name(),book.getIsSale(),book.getBook_id()};
int update = jdbcTemplate.update(sql,args);
System.out.println(update);
}
测试
@Test
public void testJdbcTemplate1(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
Book book = new Book();
book.setBook_id(1);
book.setBook_name("数据结构");
book.setIsSale("不出售");
bookService.updateBook(book);
}
测试结果
3.3 删除操作
核心部分
@Override
public void deleteBook(int id) {
//1、创建sql语句
String sql = "delete from t_book where book_id=?";
//2、调用方法
int update = jdbcTemplate.update(sql,id);
System.out.println(update);
}
测试
@Test
public void testJdbcTemplate2(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
Book book = new Book();
book.setBook_id(1);
bookService.deleteBook(book.getBook_id());
}
测试结果
3.4 查询操作(查询返回某个值)
1、查询表里面有多少条记录,返回是某个值
2、使用 JdbcTemplate 实现查询返回某个值代码
核心
第一个参数:sql 语句
第二个参数:返回类型 Class
@Override
public int selectCount() {
String sql ="select count(*) from t_book";
Integer count = jdbcTemplate.queryForObject(sql,Integer.class);
return count;
}
测试
@Test
public void testJdbcTemplate3(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
System.out.println(bookService.selectCount());
}
测试结果
3.5 测试返回查询对象
第一个参数:sql 语句
第二个参数:RowMapper 是接口,针对返回不同类型数据,使用这个接口里面实现类完成
数据封装
第三个参数:sql 语句值
核心
@Override
public Book selectOneBook(int id) {
String sql = "select * from t_book where book_id = ?";
Book book = jdbcTemplate.queryForObject(sql,new BeanPropertyRowMapper<Book>(Book.class),id);
return book;
}
测试
@Test
public void testJdbcTemplate3(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
System.out.println(bookService.selectBookOne(1));
}
测试结果
3.6 查询返回集合
第一个参数:sql 语句
第二个参数:RowMapper 是接口,针对返回不同类型数据,使用这个接口里面实现类完成
数据封装
第三个参数:sql 语句值
@Override
public List<Book> selectAllBook() {
String sql = "select * from t_book";
List<Book> bookList = jdbcTemplate.query(sql,new BeanPropertyRowMapper<Book>(Book.class));
return bookList;
}
测试
@Test
public void testJdbcTemplate3(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
System.out.println(bookService.selectBookAll());
}
测试结果
4、完整的代码
4.1 BookDao.java
/**
* @author Lenovo
* @version 1.0
* @data 2022/10/23 15:53
*/
public interface BookDao {
/**
* 添加
* @param book
*/
void addBook(Book book);
/**
* 修改
* @param book
*/
void updateBook(Book book);
/**
* 删除
* @param id
*/
void deleteBook(int id);
/**
* 查询表记录数
*/
int selectCount();
/**
* 查询对象
*/
Book selectOneBook(int id);
/**
* 查询全部对象
*/
List<Book> selectAllBook();
}
4.2 BookDaoImpl.java
/**
* @author Lenovo
* @version 1.0
* @data 2022/10/23 15:53
*/
@Repository
public class BookDaoImpl implements BookDao{
/**
* 注入jdbcTemplate
*/
@Autowired
private JdbcTemplate jdbcTemplate;
@Override
public void addBook(Book book) {
//1、创建sql语句
String sql = "insert into t_book values(?,?,?)";
//2、调用方法
Object [] args ={book.getBook_id(),book.getBook_name(),book.getIsSale()};
int update = jdbcTemplate.update(sql,args);
System.out.println(update);
}
@Override
public void updateBook(Book book) {
//1、创建sql语句
String sql = "update t_book set book_name=?,isSale=? where book_id=?";
//2、调用方法
Object [] args ={book.getBook_name(),book.getIsSale(),book.getBook_id()};
int update = jdbcTemplate.update(sql,args);
System.out.println(update);
}
@Override
public void deleteBook(int id) {
//1、创建sql语句
String sql = "delete from t_book where book_id=?";
//2、调用方法
int update = jdbcTemplate.update(sql,id);
System.out.println(update);
}
@Override
public int selectCount() {
String sql ="select count(*) from t_book";
Integer count = jdbcTemplate.queryForObject(sql,Integer.class);
return count;
}
@Override
public Book selectOneBook(int id) {
String sql = "select * from t_book where book_id = ?";
Book book = jdbcTemplate.queryForObject(sql,new BeanPropertyRowMapper<Book>(Book.class),id);
return book;
}
@Override
public List<Book> selectAllBook() {
String sql = "select * from t_book";
List<Book> bookList = jdbcTemplate.query(sql,new BeanPropertyRowMapper<Book>(Book.class));
return bookList;
}
}
4.3 BookService.java
/**
* @author Lenovo
* @version 1.0
* @data 2022/10/23 15:53
*/
@Service
public class BookService {
/**
* 注入dao
*/
@Autowired
private BookDao bookDao;
/**
* 添加书
* @param book
*/
public void addBook(Book book){
bookDao.addBook(book);
}
/**
* 修改书籍
* @param book
*/
public void updateBook(Book book){
bookDao.updateBook(book);
}
/**
* 删除书籍
* @param id
*/
public void deleteBook(int id){
bookDao.deleteBook(id);
}
/**
* 查询
* @return
*/
public int selectCount(){
return bookDao.selectCount();
}
/**
* 查询对象
* @return
*/
public Book selectBookOne(int id){
return bookDao.selectOneBook(id);
}
/**
* 查询全部对象
* @return
*/
public List<Book> selectBookAll(){
return bookDao.selectAllBook();
}
}
4.4 bean.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
<!--开启组件扫描-->
<context:component-scan base-package="com.zyz"></context:component-scan>
<!-- 数据库连接池 -->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
destroy-method="close">
<property name="url" value="jdbc:mysql://localhost:3306/user_db" />
<property name="username" value="root" />
<property name="password" value="root" />
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
</bean>
<!--jdbcTemplate对象-->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<!--注入dataSource-->
<property name="dataSource" ref="dataSource"></property>
</bean>
</beans>
4.5 测试
/**
* @author Lenovo
* @version 1.0
* @data 2022/10/23 16:26
*/
public class TestDemo {
@Test
public void testJdbcTemplate(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
Book book = new Book();
book.setBook_id(2);
book.setBook_name("C语言");
book.setIsSale("出售");
bookService.addBook(book);
}
@Test
public void testJdbcTemplate1(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
Book book = new Book();
book.setBook_id(1);
book.setBook_name("数据结构");
book.setIsSale("不出售");
bookService.updateBook(book);
}
@Test
public void testJdbcTemplate2(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
Book book = new Book();
book.setBook_id(1);
bookService.deleteBook(book.getBook_id());
}
@Test
public void testJdbcTemplate3(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
BookService bookService = context.getBean("bookService", BookService.class);
// System.out.println(bookService.selectCount());
// System.out.println(bookService.selectBookOne(1));
System.out.println(bookService.selectBookAll());
}
}
5、后语
学无止境。下一篇写增删改的批量操作