Spring的JDBC框架承担了资源管理和异常处理的工作，将数据访问的样板代码抽象到模板类之中，从而简化了JDBC代码，使我们只需编写从数据库读写数据所必需的代码。
Spring为JDBC提供了三个模板类供选择：
-
JdbcTemplate
最基本的Spring JDBC模板，支持简单的JDBC数据访问功能以及基于索引参数的查询，上层接口为JdbcOperations
This is the central class in the JDBC core package. It simplifies the use of JDBC and helps to avoid common errors. It executes core JDBC workflow, leaving application code to provide SQL and extract results. This class executes SQL queries or updates, initiating iteration over ResultSets and catching JDBC exceptions and translating them to the generic, more informative exception hierarchy defined in the org.springframework.dao package. -
NamedParameterJdbcTemplate
使用该模板类进行查询时可以将值以命名参数的形式绑定到sql中，而不是使用简单的索引参数，上层接口为NamedParameterJdbcOperations
Template class with a basic set of JDBC operations, allowing the useof named parameters rather than traditional '?' placeholders. -
SimpleJdbcTemplate
已废弃
导入依赖
在 pom.xml 中添加对 JdbcTemplate 的依赖
org.springframework.boot
spring-boot-starter-jdbc
mysql
mysql-connector-java
runtime
org.springframework.boot
spring-boot-starter-web
连接数据库
在application.yml中添加如下配置。值得注意的是，Spring Boot默认会自动配置DataSource，它将优先采用HikariCP连接池，如果没有该依赖的情况则选取 Tomcat pooling DataSource ，如果前两者都不可用最后选取 Commons DBCP2
。通过spring.datasource.type属性可以指定其它种类的连接池
application.yml
spring:
application:
name: spring-boot-jdbc
datasource:
url: jdbc:mysql://localhost:3306/test_db?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useSSL=false
username: root
password: mysql123
driver-class-name: com.mysql.jdbc.Driver
启动项目，通过日志，可以看到默认情况下注入的是HikariDataSource
2018-07-07 15:28:37.925 INFO 2316 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Bean with name 'dataSource' has been autodetected for JMX exposure
2018-07-07 15:28:37.932 INFO 2316 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Located MBean 'dataSource': registering with JMX server as MBean [com.zaxxer.hikari:name=dataSource,type=HikariDataSource]
2018-07-07 15:28:37.978 INFO 2316 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
具体编码
表结构
创建tb_user表
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for tb_user
-- ----------------------------
DROP TABLE IF EXISTS `tb_user`;
CREATE TABLE `tb_user` (
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '用户id',
`username` varchar(64) NOT NULL COMMENT '用户名',
`password` varchar(64) NOT NULL COMMENT '用户密码',
`birthday` date DEFAULT NULL COMMENT '用户生日',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
-- ----------------------------
-- Records of tb_user
-- ----------------------------
BEGIN;
INSERT INTO `tb_user` VALUES (1, 'aaa', '123456', '1994-08-10');
INSERT INTO `tb_user` VALUES (2, 'bbb', '123456', '1996-07-25');
INSERT INTO `tb_user` VALUES (3, 'ccc', '123456', '2000-05-01');
INSERT INTO `tb_user` VALUES (4, 'ddd', '123456', '1997-05-10');
COMMIT;
SET FOREIGN_KEY_CHECKS = 1;
实体类
package com.example.springbootjdbc.pojo;
import java.util.Date;
public class User {
/** 用户id */
private Integer id;
/** 用户名 */
private String username;
/** 用户密码 */
private String password;
/** 用户生日 */
private Date birthday;
// setters and getters ...
}
Dao层
com.example.springbootjdbc.dao.IUserDao
package com.example.springbootjdbc.dao;
import com.example.springbootjdbc.pojo.User;
import java.util.List;
public interface IUserDao {
int save(User user);
int delete(Integer id);
int update(User user);
User findById(Integer id);
List findAll();
List findList(Integer page, Integer pageSize);
}
com.example.springbootjdbc.dao.impl.UserDaoImpl
package com.example.springbootjdbc.dao.impl;
import com.example.springbootjdbc.dao.IUserDao;
import com.example.springbootjdbc.pojo.User;
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;
@Repository
public class UserDaoImpl implements IUserDao {
private final JdbcTemplate jdbcTemplate;
@Autowired
public UserDaoImpl(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
@Override
public int save(User user) {
String sql = "INSERT INTO tb_user(username, password, birthday) VALUES(?, ?, ?)";
return jdbcTemplate.update(sql, user.getUsername(), user.getPassword(), user.getBirthday());
}
@Override
public int delete(Integer id) {
String sql = "DELETE FROM tb_user WHERE id = ?";
return jdbcTemplate.update(sql, id);
}
@Override
public int update(User user) {
String sql = "UPDATE tb_user u SET u.username = ?, u.password = ?, u.birthday = ? WHERE u.id = ?";
return jdbcTemplate.update(sql, user.getUsername(), user.getPassword(), user.getBirthday(), user.getId());
}
@Override
public User findById(Integer id) {
String sql = "SELECT * FROM tb_user WHERE id = ?";
return jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(User.class), id);
}
@Override
public List findAll() {
String sql = "SELECT * FROM tb_user";
return jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(User.class));
}
@Override
public List findList(Integer page, Integer pageSize) {
String sql = "SELECT * FROM tb_user LIMIT ?, ?";
Integer offset = (page - 1) * pageSize;
return jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(User.class), offset, pageSize);
}
}
Service层
com.example.springbootjdbc.service.IUserService
package com.example.springbootjdbc.service;
import com.example.springbootjdbc.pojo.User;
import java.util.List;
public interface IUserService {
int save(User user);
int delete(Integer id);
int update(User user);
User findById(Integer id);
List findAll();
List findList(Integer page, Integer pageSize);
}
com.example.springbootjdbc.service.impl.UserServiceImpl
package com.example.springbootjdbc.service.impl;
import com.example.springbootjdbc.dao.IUserDao;
import com.example.springbootjdbc.pojo.User;
import com.example.springbootjdbc.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements IUserService {
private final IUserDao userDao;
@Autowired
public UserServiceImpl(IUserDao userDao) {
this.userDao = userDao;
}
@Override
public int save(User user) {
return userDao.save(user);
}
@Override
public int delete(Integer id) {
return userDao.delete(id);
}
@Override
public int update(User user) {
return userDao.update(user);
}
@Override
public User findById(Integer id) {
return userDao.findById(id);
}
@Override
public List findAll() {
return userDao.findAll();
}
@Override
public List findList(Integer page, Integer pageSize) {
return userDao.findList(page, pageSize);
}
}
Rest 接口
package com.example.springbootjdbc.controller;
import com.example.springbootjdbc.pojo.User;
import com.example.springbootjdbc.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.List;
@RestController
@RequestMapping("/users")
public class UserController {
private final IUserService userService;
@Autowired
public UserController(IUserService userService) {
this.userService = userService;
}
@PostMapping("")
public String saveUser(@RequestBody User user) {
int count = userService.save(user);
return count > 0 ? "success" : "fail";
}
@DeleteMapping("/{id}")
public String deleteUser(@PathVariable Integer id) {
int count = userService.delete(id);
return count > 0 ? "success" : "fail";
}
@PutMapping("/{id}")
public String updateUser(@PathVariable Integer id, @RequestParam(value = "username", required = true) String username,
@RequestParam(value = "password", required = true) String password,
@RequestParam(value = "birthday", required = true) String birthday) throws ParseException {
User updateUser = new User();
updateUser.setId(id);
updateUser.setUsername(username);
updateUser.setPassword(password);
updateUser.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse(birthday));
int count = userService.update(updateUser);
return count > 0 ? "success" : "fail";
}
@GetMapping("")
public List findList(@RequestParam(value = "page", defaultValue = "1") Integer page,
@RequestParam(value = "pageSize", defaultValue = "10") Integer pageSize) {
return userService.findList(page, pageSize);
}
@GetMapping("{id}")
public User findById(@PathVariable Integer id) {
return userService.findById(id);
}
}
附
JdbcTemplate API文档