前言
学习spring中自带的jdbcTemplate是如何操作数据库的。
先来个项目目录结构截图：
其次，先给出一个完整的xml配置文件，具体的信息解释会在后面说。
<?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:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
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.atguigu.spring5"></context:component-scan>
<!--连接数据库连接池-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
destroy-method="close">
<property name="url" value="jdbc:mysql:///user_db?useUnicode=true&characterEncoding=utf8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
<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"/>
</bean>
</beans>目录
1、在pom文件中引入相关的依赖
这儿粘贴了整个pom文件，自己使用时只拿依赖部分即可
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>atguiguLearnSpring5</artifactId>
<groupId>org.example</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>Spring5_demo5</artifactId>
<dependencies>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.10</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>5.3.22</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>5.3.3</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>5.0.5.RELEASE</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>compile</scope>
</dependency>
</dependencies>
<!--添加这个以后就是用jdk1.8编译，以致于不会出现@Override报错的情况-->
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>2、在数据库中构建表结构
3、在java包下编写实体类
Book.java
package com.atguigu.spring5.entity;
/**
* @Author 不要有情绪的 ljy
* @Date 2022/9/20 14:44
* @Description:
*/
public class Book {
private String UserId;
private String username;
private String ustatus;
public String getUserId() {
return UserId;
}
public void setUserId(String userId) {
UserId = userId;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getUstatus() {
return ustatus;
}
public void setUstatus(String ustatus) {
this.ustatus = ustatus;
}
@Override
public String toString() {
return "Book{" +
"UserId='" + UserId + '\'' +
", username='" + username + '\'' +
", ustatus='" + ustatus + '\'' +
'}';
}
}
4、编写业务层和dao层
BookDao.java
package com.atguigu.spring5.dao;
import com.atguigu.spring5.entity.Book;
/**
* @Author 不要有情绪的 ljy
* @Date 2022/9/20 14:38
* @Description:
*/
public interface BookDao {
void add(Book book);
void deleteBook(String id);
void updateBook(Book book);
void selectCount();
void selectByUser_id(String id);
void selectAll();
void selectAllByUsername(String username);
}
BookDaoImpl.java
package com.atguigu.spring5.dao;
import com.atguigu.spring5.entity.Book;
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;
/**
* @Author 不要有情绪的 ljy
* @Date 2022/9/20 14:38
* @Description:
*/
@Repository
public class BookDaoImpl implements BookDao {
//注入JdbcTemplate
@Autowired
private JdbcTemplate jdbcTemplate;
@Override
public void add(Book book) {
//1 创建sql语句
String sql = "insert into t_book values(?,?,?)";
//2 调用方法
Object[] args = {book.getUserId(), book.getUsername(), book.getUstatus()};
int update = jdbcTemplate.update(sql, args);
System.out.println(update);
}
@Override
public void deleteBook(String id) {
String sql = "delete from t_book where user_id = ?";
int delete = jdbcTemplate.update(sql, id);
System.out.println(delete);
}
@Override
public void updateBook(Book book) {
String sql = "update t_book set username = ?,ustatus=? where user_id = ?";
Object[] args = {book.getUsername(), book.getUstatus(), book.getUserId()};
int update = jdbcTemplate.update(sql, args);
System.out.println(update);
}
@Override
public void selectCount() {
String sql = "select count(*) from t_book";
Integer integer = jdbcTemplate.queryForObject(sql, Integer.class);
System.out.println(integer);
}
@Override
public void selectByUser_id(String id) {
String username = "java";
String sql = "select * from t_book where user_id = ?";
Book book = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<Book>(Book.class), id);
System.out.println(book);
}
@Override
public void selectAll() {
String sql = "select * from t_book";
List<Book> books = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Book.class));
System.out.println(books);
}
@Override
public void selectAllByUsername(String username) {
String sql = "select * from t_book where username = ?";
List<Book> books = jdbcTemplate.query(sql, new Object[]{username}, new BeanPropertyRowMapper<>(Book.class));
List<Book> books1 = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Book.class), username);
System.out.println(books);
System.out.println(books1);
}
}
BookService.java
package com.atguigu.spring5.service;
import com.atguigu.spring5.dao.BookDao;
import com.atguigu.spring5.entity.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
* @Author 不要有情绪的 ljy
* @Date 2022/9/20 14:38
* @Description:
*/
@Service
public class BookService {
@Autowired
private BookDao bookDao;
//添加的方法
public void addBook(Book book){
bookDao.add(book);
}
//删除的方法
public void deleteBook(String id) {
bookDao.deleteBook(id);
}
//更新的方法
public void updateBook(Book book) {
bookDao.updateBook(book);
}
//查询返回一共含有多少记录
public void selectCount(){
bookDao.selectCount();
}
//查询得到一个对象
public void selectByUser_id(String id) {
bookDao.selectByUser_id(id);
}
public void selectAll() {
bookDao.selectAll();
}
public void selectAllByUsername(String username) {
bookDao.selectAllByUsername(username);
}
}
5、创建spring配置文件进行配置
bean1.xml
首先开启组件扫描，即告诉程序要扫描的包，记得在上面的类中添加扫描注解（例如@Service，@Component等）
<!-- 开启组件扫描 -->
<context:component-scan base-package="com.atguigu.spring5"></context:component-scan>配置连接数据库的数据源等信息：
<!--连接数据库连接池-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
destroy-method="close">
<property name="url" value="jdbc:mysql:///user_db?useUnicode=true&characterEncoding=utf8"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
</bean>在xml文件中配置生成jdbcTemplate对象，并注入数据源属性：
<!-- JdbcTemplate对象 -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<!-- 注入dataSource -->
<property name="dataSource" ref="dataSource"/>
</bean>以上就完成了配置工作！
6、编写测试类
TestBook.java
package com.atguigu.spring5.test;
import com.atguigu.spring5.entity.Book;
import com.atguigu.spring5.service.BookService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* @Author 不要有情绪的 ljy
* @Date 2022/9/20 18:38
* @Description:
*/
public class TestBook {
@Test
public void testJdbcTemplate(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
BookService bookService = context.getBean("bookService", BookService.class);
Book book = new Book();
book.setUserId("1");
book.setUsername("java");
book.setUstatus("a");
// bookService.addBook(book);
// bookService.updateBook(book);
// bookService.deleteBook("1");
// bookService.selectCount();
// bookService.selectByUser_id("2");
// bookService.selectAll();
bookService.selectAllByUsername("java");
}
}
7、测试结果显示
此时数据库中的数据为：
得到的测试结果为：
8、总结
spring使用jdbcTemplate可以完成与数据库的交互，可以手写所有的sql语句，给开发人员一种比较直观的感觉。整体上就是引入相关依赖，构建业务逻辑，然后编写相应的sql语句完成数据库操作。当然里面关于所有的sql操作还没有进行完整的学习，例如批量增加等等，我想所有的操作类似而已。
学习之所以会想睡觉，是因为那是梦开始的地方。
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