一、JdbcTemplate的介绍
Spring框架针对数据库开发中的应用提供了 JdbcTemplate类,该类是 Spring 对 JDBC 支持的核心,它提供了所有对数据库操作功能的支持。JdbcTemplate主要提供以下几种方法:
方法 | 描述 |
---|---|
execute方法 | 可以用于执行任何SQL语句,一般用于执行DDL语句 |
update方法以及batchUpdate方法 | update方法用于执行增加、修改、删除等语句。batchUpdate方法用于执行批处理相关语句。 |
query方法以及queryForXXX方法 | 用于执行查询相关语句 |
call方法 | 用于执行存储过程、函数相关语句。 |
使用JdbcTemplate要导入Spring的数据库模块的三个jar包和mysql数据库的jar包如下:
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.35</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.2.6.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-orm -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>5.2.6.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.2.6.RELEASE</version>
</dependency>
二、JdbcTemplate实现数据库的增删改查
(1)创建外部配置文件jdbc.properties
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.userName=root
jdbc.password=root
(2)创建bean.xml,配置数据源、jdbcTemplate以及注解扫描的包。
<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"><!--引入context名称空间-->
<!-- 配置注解扫描的包 -->
<context:component-scan base-package="com.yht.example7"></context:component-scan>
<!--引入外部属性文件-->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!--配置连接池-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${jdbc.driverClass}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.userName}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
<!-- 配置jdbcTemplate -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
</beans>
(3)创建t_user表并插入部分数据。
create table t_user(
id int primary key auto_increment,
name varchar(20),
address varchar(20));
insert into t_user(name, address) values("张玉","山西");
insert into t_user(name, address) values("李红","江西");
insert into t_user(name, address) values("江峰","福建");
(4)创建实体类User
public class User {
private Integer id;
private String name;
private String address;
public User() {
}
public User(String name, String address) {
this.name = name;
this.address = address;
}
public User(Integer id, String name, String address) {
this.id = id;
this.name = name;
this.address = address;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}
(5)创建UserService
@Service
public class UserService {
@Autowired
private IUserDao userDao;
/**
* 添加用户
*/
public void addUser(User user){
userDao.addUser(user);
}
/**
* 删除用户
*/
public void deleteUser(int id){
userDao.deleteUser(id);
}
/**
* 更新用户
*/
public void updateUser(User user){
userDao.updateUser(user);
}
/**
* 查询数据库中数据总数
*/
public void getCount(){
userDao.getCount();
}
/**
* 查询单个用户
*/
public void findOne(int id){
userDao.findOne(id);
}
/**
* 查询所有用户
*/
public void findAll(){
userDao.findAll();
}
}
(6)创建IUserDao和实现类UserDaoImpl
public interface IUserDao {
/**
* 添加用户
*/
void addUser(User user);
/**
* 删除用户
*/
void deleteUser(int id);
/**
* 更新用户
*/
void updateUser(User user);
/**
* 查询数据库中数据总数
*/
void getCount();
/**
* 查询单个用户
*/
void findOne(int id);
/**
* 查询所有用户
*/
void findAll();
}
@Repository
public class UserDaoImpl implements IUserDao {
@Autowired
private JdbcTemplate jdbcTemplate;
@Override
public void addUser(User user) {
String sql = "insert into t_user(name, address) values(?,?)";
jdbcTemplate.update(sql, user.getName(), user.getAddress());
}
@Override
public void deleteUser(int id) {
String sql = "delete from t_user where id = ?";
jdbcTemplate.update(sql, id);
}
@Override
public void updateUser(User user) {
String sql = "update t_user set name =?, address=? where id = ?";
jdbcTemplate.update(sql, user.getName(), user.getAddress(), user.getId());
}
@Override
public void getCount() {
String sql = "select count(*) from t_user";
Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
System.out.println(count);
}
@Override
public void findOne(int id) {
String sql = "select * from t_user where id = ?";
User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
System.out.println(user);
}
@Override
public void findAll() {
String sql = "select * from t_user";
List<User> lists = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
System.out.println(lists);
}
}
(7)进行单元测试
public class JdbcTemplateTest {
UserService userService = null;
@Before
public void init(){
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
userService = context.getBean("userService", UserService.class);
}
@Test
public void testAddUser(){
userService.addUser(new User("YHT", "陕西"));
}
@Test
public void testFindCount(){
userService.getCount();
}
@Test
public void testFindOne(){
userService.findOne(3);
}
@Test
public void testFindAll(){
userService.findAll();
}
@Test
public void testUpdateUser(){
User user = new User(3, "张倩","北京");
userService.updateUser(user);
}
@Test
public void testDeleteUser(){
userService.deleteUser(2);
}
}
三、JdbcTemplate实现数据库的批量操作
以批量添加用户为例:
(1)分别在UserService、IUserDao、UserDaoImpl中添加方法——batchAddUser()
/**
* 批量添加数据
*/
public void batchAddUser(List<Object[]> lists){
userDao.batchAddUser(lists);
}
/**
* 批量添加用户
*/
void batchAddUser(List<Object[]> lists);
@Override
public void batchAddUser(List<Object[]> lists) {
String sql = "insert into t_user(name, address) values(?,?)";
jdbcTemplate.batchUpdate(sql, lists);
}
(2)进行单元测试
@Test
public void testBatch(){
List<Object[]> batchArgs=new ArrayList<>();
batchArgs.add(new Object[]{"张三","新疆"});
batchArgs.add(new Object[]{"李四","吉林"});
batchArgs.add(new Object[]{"王五","河北"});
userService.batchAddUser(batchArgs);
}