什麼是JdbcTemplate?
JdbcTemplate是Spring的一部分,是對數據庫的操作在jdbc的封裝,處理了資源的建立和釋放(不需要我們管理連接了),我們只需要提供SQL語句(不需要我們設置參數了)和提取結果(查詢時候可以直接返回對應的實體類),使JDBC更加易於使用。
JdbcTemplate使用spring的注入功能,把DataSource註冊到JdbcTemplate之中。
spring源碼地址
爲什麼需要JdbcTemplate?
使用jdbc時,每次都需要自己獲取PreparedStatement,輸入sql語句參數,關閉連接等操作。造成操作冗餘。影響我們打代碼的效率。有了JDBCTemplate以後就可以只寫SQL語句就可以了。
JdbcTemplate的基本使用步驟
本教程使用的開發IED爲IDEA基於maven
1.pom.xml中引入相關依賴
對於JdbcTemplate的使用,除了基礎的spring依賴之外,需要的相關依賴有
1.mysql-connector
2.spring jdbc
3.druid
pom.xml文件如下:
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.7.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.mzc</groupId>
<artifactId>infotest</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>infotest</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.9</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
2.編寫配置
application.properties文件如下:
server.port=8081
spring.application.name=travels
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/jdbctest?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=277171
數據庫有關的信息,例如spring.datasource.url、usename以及password,根據自己的實際情況進行配置
3.編寫持久層,這裏以Book進行舉例
Book.java
package com.mzc.Model;
/**
* @author jikeMisma
* @date 2020/6/19 - 10:51
*/
public class Book {
int id;
String bookname;
String author;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getBookname() {
return bookname;
}
public void setBookname(String bookname) {
this.bookname = bookname;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
}
4.編寫DAO層
BookDao.java
package com.mzc.Dao.impl;
import com.mzc.Model.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 jikeMisma
* @date 2020/6/19 - 10:52
*/
@Repository
public class BookDao {
@Autowired
JdbcTemplate jdbcTemplate;
public int addBook(Book book) {
return jdbcTemplate.update("insert into t_book(bookname,author) values (?,?)", book.getBookname(), book.getAuthor());
}
public int updateBook(Book book) {
return jdbcTemplate.update("insert into t_book set bookname=?,author=? where id =?", book.getBookname(), book.getAuthor(), book.getId());
}
public int deleteBookBtId(Integer id) {
return jdbcTemplate.update("delete from t_book where id=?", id);
}
public Book getBookById(Integer id){
return jdbcTemplate.queryForObject("select * from t_book where id=?",new BeanPropertyRowMapper<>(Book.class),id);
}
public List<Book> getAllBooks(){
return jdbcTemplate.query("select * from t_book",new BeanPropertyRowMapper<>(Book.class));
}
}
5.編寫Service層
BookService .java
package com.mzc.Service.impl;
import com.mzc.Dao.impl.BookDao;
import com.mzc.Model.Book;
import lombok.experimental.Accessors;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
/**
* @author jikeMisma
* @date 2020/6/19 - 11:13
*/
@Service
public class BookService {
@Autowired
BookDao bookDao;
public int addBook(Book book){
return bookDao.addBook(book);
}
public int updateBook(Book book){
return bookDao.updateBook(book);
}
public int deleteBookBtId(Integer id){
return bookDao.deleteBookBtId(id);
}
public Book getBookById(Integer id){
return bookDao.getBookById(id);
}
public List<Book> getAllBooks(){
return bookDao.getAllBooks();
}
}
6.創建Controller進行調用
package com.mzc.Controller;
import com.mzc.Model.Book;
import com.mzc.Service.impl.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
/**
* @author jikeMisma
* @date 2020/6/19 - 11:16
*/
@Controller
public class BookController {
@Autowired
BookService bookService;
@GetMapping("bookOps")
public void bookOps(){
Book b1 = new Book();
b1.setBookname("Redis設計與實現");
b1.setAuthor("黃健宏");
int i = bookService.addBook(b1);
System.out.println("addBood>>>"+i);
Book b2 = new Book();
b2.setBookname("大數據技術原理與應用");
b2.setAuthor("林子雨");
int updatebook = bookService.addBook(b2);
System.out.println("updateBook>>>"+updatebook);
Book b3 = bookService.getBookById(5);
System.out.println("getBookByid>>>"+b3);
}
}
這時候編寫的數據就可以寫入數據庫進行持久化了。
運行截圖如下
啓動springBoot項目
在瀏覽器訪問對應的地址
查看數據庫數據是否入庫: