SpringBoot（四） SpringBoot整合JdbcTemplate

一、数据准备
CREATE TABLE `tb_user` (
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'ID',
`username` varchar(50) NOT NULL COMMENT '用户名',
`age` int(11) NOT NULL COMMENT '年龄',
`ctm` datetime NOT NULL COMMENT '创建时间',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
INSERT INTO `db_test`.`tb_user` (`username`, `age`, `ctm`) VALUES('张三', '18', NOW()) ;
INSERT INTO `db_test`.`tb_user` (`username`, `age`, `ctm`) VALUES('李四', '20', NOW()) ;
INSERT INTO `db_test`.`tb_user` (`username`, `age`, `ctm`) VALUES('王五', '19', NOW()) ;

二、引入依赖：
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<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
       <version>2.0.4.RELEASE</version>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
    <!-- jdbcTemplate -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!-- MySQL连接 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-api -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.11.2</version>
        </dependency>
        <!-- Spring-Mybatis -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.0</version>
            </dependency>
        <!-- MySQL -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
         </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
         </dependency>
         <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
         </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                <fork>true</fork>
                </configuration>
            </plugin>
        </plugins>
  </build>
</project>

三、数据库配置文件
一如既往，我们采用yaml文件配置，当然properties文件也是一样。

注意点，SpringBoot默认采用tomcat-jdbc连接池，如果需要C3P0，DBCP，Druid等作为连接池，需要加入相关依赖以及配置，这里不作说明，采用默认配置即可。

spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/db_user
username: root
password: root
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四、代码

项目结构如下：

实体类User.class：

package com.demo.bean;
import java.util.Date;

public class User {

    public  int id;
    public  String username;
    public  int age;
    public  Date ctm;

    public User() {
    }

    public User(String username, int age) {
        this.username = username;
        this.age = age;
        this.ctm = new Date();
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Date getCtm() {
        return ctm;
    }

    public void setCtm(Date ctm) {
        this.ctm = ctm;
    }

}

UserDao：

package com.demo.dao;

import java.util.List;

import com.demo.bean.User;

public interface UserDao {

    public User getUserById(Integer id);

    public List<User> getUserList();

}

UserDaoImpl：

package com.demo.dao.impl;

import java.util.List;

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 com.demo.bean.User;
import com.demo.dao.UserDao;

@Repository
public class UserDaoImpl implements UserDao{

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public User getUserById(Integer id) {
        List<User> list = jdbcTemplate.query("select * from tb_user where id = ?", new Object[]{id}, new BeanPropertyRowMapper(User.class));
        if(list!=null && list.size()>0){
            return list.get(0);
        }else{
            return null;
        }
    }

    @Override
    public List<User> getUserList() {
        List<User> list = jdbcTemplate.query("select * from tb_user", new Object[]{}, new BeanPropertyRowMapper(User.class));
        if(list!=null && list.size()>0){
            return list;
        }else{
            return null;
        }
    }

}

UserService：

package com.demo.service;

import java.util.List;

import com.demo.bean.User;

public interface UserService {

    User getUserById(Integer id);

    public List<User> getUserList();

}

UserServiceImpl：

package com.demo.service.impl;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.demo.bean.User;
import com.demo.dao.UserDao;
import com.demo.service.UserService;

@Service
public class UserServiceImpl implements UserService{

    @Autowired
    private UserDao userDao;

    @Override
    public User getUserById(Integer id) {
        return userDao.getUserById(id);
    }

    @Override
    public List<User> getUserList() {
        return userDao.getUserList();
    }

}

UserController：

package com.demo.web;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.demo.bean.JsonResult;
import com.demo.bean.User;
import com.demo.service.UserService;

@RestController
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping(value = "user/{id}", method = RequestMethod.GET)
    public ResponseEntity<JsonResult> getUserById (@PathVariable(value = "id") Integer id){
        JsonResult r = new JsonResult();
        try {
            User user = userService.getUserById(id);
            r.setResult(user);
            r.setStatus("ok");
        } catch (Exception e) {
            r.setResult(e.getClass().getName() + ":" + e.getMessage());
            r.setStatus("error");
            e.printStackTrace();
        }
        return ResponseEntity.ok(r);
    }

    /**
     * 查询用户列表
     * @return
     */
    @RequestMapping(value = "users", method = RequestMethod.GET)
    public ResponseEntity<JsonResult> getUserList (){
        JsonResult r = new JsonResult();
        try {
            List<User> users = userService.getUserList();
            r.setResult(users);
            r.setStatus("ok");
        } catch (Exception e) {
            r.setResult(e.getClass().getName() + ":" + e.getMessage());
            r.setStatus("error");
            e.printStackTrace();
        }
        return ResponseEntity.ok(r);
    }

}

JsonResult:

package com.demo.bean;

public class JsonResult {

    private String status = null;

    private Object result = null;

    public JsonResult status(String status) {
        this.status = status;
        return this;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public Object getResult() {
        return result;
    }

    public void setResult(Object result) {
        this.result = result;
    }

}

测试：

访问：

http://localhost:8080/user/1

http://localhost:8080/users