本文意在使用最簡單的方式讓專案連線資料庫，後續還會將一些總結的經驗逐步發出來供大家參考

注：這裡連線的是oracle，如果要換mysql把依賴換一下，配置檔案裡連線配置改一改就行。

1、建立springboot專案，主要步驟如下，

     具體步驟參見之前的專案建立文件 1、springboot工程新建（單模組）

2、pom.xml檔案

pom.xml由spring boot自動生成也可以自行修改，注意已經包含了web, jdbc, oracle的依賴配置

<?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>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version
 
>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <
 
project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.1.17.RELEASE</spring-boot.version>
    </properties>

    <dependencies>
        <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>com.oracle</groupId>
            <artifactId>ojdbc6</artifactId>
            <version>11.2.0.3</version>
        </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>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.1.17.RELEASE</version>
                <configuration>
                    <mainClass>com.example.demo.DemoApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

3、配置資料來源

開啟檔案：application.properties，該檔案在 src -> main -> resources 目錄，配置數

# 應用名稱
spring.application.name=demo
# 應用服務 WEB 訪問埠
server.port=8080

# 資料庫設定
spring.datasource.driverClassName=oracle.jdbc.OracleDriver
spring.datasource.url=jdbc:oracle:thin:@192.168.0.100:1521:orcl
spring.datasource.username=zy
spring.datasource.password=1

4、資料庫

oracle裡建立表及初始化表
注：oralce中建立的使用者為zy，密碼為1
CREATE TABLE TEST_BLOCK_T   
(
  BLOCK_ID         VARCHAR2(10 BYTE) PRIMARY   KEY,    --編碼
  BLOCK_NAME       VARCHAR2(200 BYTE)                  --資源名稱 
); 
 Insert into TEST_BLOCK_T (BLOCK_ID, BLOCK_NAME) Values ('1', 'java');
COMMIT;

5、建立HelloController.java

package com.example.demo.controller;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/hello")
public class HelloController {

    @Autowired
    JdbcTemplate jdbcTemplate;

    @GetMapping("/list")
    @ResponseBody
    public String index() {

        String sql = "SELECT BLOCK_NAME FROM TEST_BLOCK_T WHERE BLOCK_ID = ?";

        // 通過jdbcTemplate查詢資料庫
        String mobile = (String) jdbcTemplate.queryForObject(
                sql, new Object[]{1}, String.class);

        return "Hello " + mobile;
    }
}

6、啟動專案訪問專案