3、springboot连接数据库

本文意在使用最简单的方式让项目连接数据库，后续还会将一些总结的经验逐步发出来供大家参考

注：这里连接的是oracle，如果要换mysql把依赖换一下，配置文件里连接配置改一改就行。

1、创建springboot项目，主要步骤如下，

     具体步骤参见之前的项目创建文档

2、pom.xml文件

pom.xml由spring boot自动生成也可以自行修改，注意已经包含了web, jdbc, oracle的依赖配置

<?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>4.0.0modelVersion>
    <groupId>com.examplegroupId>
    <artifactId>demoartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <name>demoname>
    <description>Demo project for Spring Bootdescription>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-jdbcartifactId>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>

        <dependency>
            <groupId>com.oraclegroupId>
            <artifactId>ojdbc6artifactId>
            <version>11.2.0.3version>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintagegroupId>
                    <artifactId>junit-vintage-engineartifactId>
                exclusion>
            exclusions>
        dependency>
    dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-dependenciesartifactId>
                <version>${spring-boot.version}version>
                <type>pomtype>
                <scope>importscope>
            dependency>
        dependencies>
    dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.pluginsgroupId>
                <artifactId>maven-compiler-pluginartifactId>
                <version>3.8.1version>
                <configuration>
                    <source>1.8source>
                    <target>1.8target>
                    <encoding>UTF-8encoding>
                configuration>
            plugin>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
                <version>2.1.17.RELEASEversion>
                <configuration>
                    <mainClass>com.example.demo.DemoApplicationmainClass>
                configuration>
                <executions>
                    <execution>
                        <id>repackageid>
                        <goals>
                            <goal>repackagegoal>
                        goals>
                    execution>
                executions>
            plugin>
        plugins>
    build>

project>

3、配置数据源

打开文件：application.properties，该文件在 src -> main -> resources 目录，配置数

# 应用名称
spring.application.name=demo
# 应用服务 WEB 访问端口
server.port=8080

# 数据库设置
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、数据库

oracle里创建表及初始化表
注：oralce中创建的用户为zy，密码为1
CREATE TABLE TEST_BLOCK_T   
(
  BLOCK_ID         VARCHAR2(10 BYTE) PRIMARY   KEY,    --编码
  BLOCK_NAME       VARCHAR2(200 BYTE)                  --资源名称 
); 
 Insert into TEST_BLOCK_T (BLOCK_ID, BLOCK_NAME) Values ('1', 'java');
COMMIT;

5、创建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 = ?";

        // 通过jdbcTemplate查询数据库
        String mobile = (String) jdbcTemplate.queryForObject(
                sql, new Object[]{1}, String.class);

        return "Hello " + mobile;
    }
}

6、启动项目访问项目