概述
JdbcTemplate是Spring 框架对 JDBC 的封装，使用 JdbcTemplate 可以方便地操作数据库
准备工作
引入相关依赖
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<!--操作数据库相关jar-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
</dependency>
<!--Spring-tx提供了非常灵活的事务管理抽象-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
</dependency>
<!-- mysql驱动包 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
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配置文件
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<?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:p="http://www.springframework.org/schema/p"
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">
<context:property-placeholder location="classpath:db.properties"/>
<context:component-scan base-package="com.eh.eden.spring.demo" use-default-filters="false">
<context:include-filter type="annotation"
expression="org.springframework.stereotype.Service"/>
<context:include-filter type="annotation"
expression="org.springframework.stereotype.Repository"/>
</context:component-scan>
<!--step1: 配置数据库连接池-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${driver}"></property>
<property name="url" value="${url}"></property>
<property name="username" value="${username}"></property>
<property name="password" value="${password}"></property>
</bean>
<!--step2: 引入jdbcTemplate-->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"/>
</bean>
</beans>
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用法演示
相关测试类
Emp.java
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package com.eh.eden.spring.demo.bean;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class Emp {
private Integer id;
private String lastName;
private String gender;
private String email;
private Integer deptId;
}
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EmpDao.java
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package com.eh.eden.spring.demo.dao;
import com.eh.eden.spring.demo.bean.Emp;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.stereotype.Repository;
import java.sql.PreparedStatement;
@Repository
public class EmpDao {
private static final Logger logger = LoggerFactory.getLogger(EmpDao.class);
@Autowired
private JdbcTemplate jdbcTemplate;
public Integer add(Emp emp) {
GeneratedKeyHolder keyHolder = new GeneratedKeyHolder();
String sql = "insert into tbl_employee(last_name, gender, email,dept_id) values(?,?,?,?)";
int count = jdbcTemplate.update(con -> {
PreparedStatement psst = con.prepareStatement(sql, new String[]{"id"});
psst.setString(1, emp.getLastName());
psst.setString(2, emp.getGender());
psst.setString(3, emp.getEmail());
psst.setInt(4, emp.getDeptId());
return psst;
}, keyHolder);
logger.info("========>添加count: {}", count);
if (count == 1) {
return keyHolder.getKey().intValue();
} else {
return null;
}
}
public void delete(Integer id) {
String sql = "delete from tbl_employee where id=?";
int count = jdbcTemplate.update(sql, id);
logger.info("========>删除count: {}", count);
}
public void updateEmailById(Integer id, String email) {
String sql = "update tbl_employee set email=? where id =?";
Object[] args = {email, id};
int count = jdbcTemplate.update(sql, args);
logger.info("========>更新count: {}", count);
}
public void select(Integer id) {
String sql = "select * from tbl_employee where id=?";
Emp emp = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(Emp.class), id);
logger.info("========>查询结果: {}", emp);
}
}
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EmpService.java
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package com.eh.eden.spring.demo.service;
import com.eh.eden.spring.demo.bean.Emp;
import com.eh.eden.spring.demo.dao.EmpDao;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Service;
@Service
public class EmpService {
private static final Logger logger = LoggerFactory.getLogger(EmpService.class);
@Autowired
private EmpDao empDao;
// 增
public Integer add(Emp emp) {
return empDao.add(emp);
}
// 删
public void delete(Integer id) {
empDao.delete(id);
}
// 改
public void updateEmailById(Integer id, String email) {
empDao.updateEmailById(id, email);
}
// 查
public void select(Integer id) {
empDao.select(id);
}
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
EmpService empService = context.getBean("empService", EmpService.class);
// 增
Integer id = empService.add(new Emp(null, "燕青", "1", "yq@gmail.com", 2));
if (id == null) {
logger.info("测试有误");
}
// 查
empService.select(id);
// 改
empService.updateEmailById(id, "高衙内@gmail.com");
// 删
empService.delete(id);
}
}
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运行结果：
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20201013 02:12:07 [main] INFO com.alibaba.druid.pool.DruidDataSource - {dataSource-1} inited
20201013 02:12:07 [main] INFO com.eh.eden.spring.demo.dao.EmpDao - ========>添加count: 1
20201013 02:12:07 [main] INFO com.eh.eden.spring.demo.dao.EmpDao - ========>查询结果: Emp(id=20019, lastName=燕青, gender=1, email=yq@gmail.com, deptId=2)
20201013 02:12:07 [main] INFO com.eh.eden.spring.demo.dao.EmpDao - ========>更新count: 1
20201013 02:12:07 [main] INFO com.eh.eden.spring.demo.dao.EmpDao - ========>删除count: 1
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说明
查询返回某个值
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Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
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查询返回对象
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/*
queryForObject方法中：
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
*/
Book book = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<Book>(Book.class), id);
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查询返回集合
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List<Book> bookList = jdbcTemplate.query(sql, new BeanPropertyRowMapper<Book>(Book.class));
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批量操作
批量添加
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//批量添加
@Override
public void batchAddBook(List<Object[]> batchArgs) {
String sql = "insert into t_book values(?,?,?)";
//batchUpdate方法 第一个参数：sql语句 第二个参数：List集合，添加多条记录数据
int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
System.out.println(Arrays.toString(ints));
}
//批量添加测试
List<Object[]> batchArgs = new ArrayList<>();
Object[] o1 = {"3","java","a"};
Object[] o2 = {"4","c++","b"};
Object[] o3 = {"5","MySQL","c"};
batchArgs.add(o1);
batchArgs.add(o2);
batchArgs.add(o3);
//调用批量添加
bookService.batchAdd(batchArgs);
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批量修改
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//批量修改(同批量添加一样，调用同一个方法)
@Override
public void batchUpdateBook(List<Object[]> batchArgs) {
String sql = "update t_book set username=?,ustatus=? where user_id=?";
int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
System.out.println(Arrays.toString(ints));
}
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批量删除