springboot+tomcat+jndi访问数据库

　　一、主要代码

　　pom.xml

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.leiyuke</groupId>
    <artifactId>databaseDemo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath />
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <!-- web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.1.1</version>
        </dependency>
        
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-dbcp2</artifactId>
        </dependency>

        <!-- 修改后立即生效 热部署 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>springloaded</artifactId>
            <version>1.2.8.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
        <finalName>databaseDemo</finalName>
    </build>
</project>

　　src/main/resources/application.yml

spring:
  datasource:
    jndi-name: test-jndi

mybatis:
  type-aliases-package: com.leiyuke.database.entity
  config-location=classpath: mybatis/mybatis.cfg.xml
  mapper-locations: classpath:mybatis/mapper/**/*.xml  
  
logging:
  level:
    root: info

　　src/main/resources/mybatis/mybatis.cfg.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>

    <settings>
        <setting name="cacheEnabled" value="true" /><!-- 二级缓存开启 -->
    </settings>

</configuration>

　　src/main/resources/mybatis/mybatis/UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.leiyuke.database.mapper.UserMapper">
    <select id="getAll" resultType="User">
        select id,name,age from t_user;
    </select>
</mapper>

　　App.java

package com.leiyuke.database;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages = "com.leiyuke")
public class App extends SpringBootServletInitializer{
    
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
    
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(App.class);
    }
}

　　DataSourceConfig.java

package com.leiyuke.database;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.jdbc.datasource.lookup.JndiDataSourceLookup;

@Configurable
@MapperScan(basePackages= {"com.leiyuke.database.mapper"},sqlSessionFactoryRef="test1SqlSessionTemplate")
public class DataSourceConfig {

    @Bean("ds1")
    @Primary
    public DataSource dataSourceJndi() {
        JndiDataSourceLookup dataSourceLookup = new JndiDataSourceLookup();
        DataSource dataSource = dataSourceLookup.getDataSource("test-jndi");
        return dataSource;
    }
    
    @Bean(name = "test1SqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory(@Qualifier("ds1") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource);
        sessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/**/*.xml"));
        return sessionFactoryBean.getObject();
    }
    
    @Bean(name = "test1TransactionManager")
    public DataSourceTransactionManager testTransactionManager(@Qualifier("ds1") DataSource dataSource) {
        return new DataSourceTransactionManager((javax.sql.DataSource) dataSource);
    }
    
    @Bean(name = "test1SqlSessionTemplate")
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

　　UserController.java

package com.leiyuke.database.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.leiyuke.database.entity.User;
import com.leiyuke.database.service.UserService;

@RestController
@RequestMapping("/user")
public class UserController {
    
    @Autowired
    private UserService userService;
    
    @RequestMapping("/getAll")
    public List<User> getAll(Model model) {
        List<User> list=userService.getAll(); 
        return list;
    }
}

　　UserMapper.java

package com.leiyuke.database.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Mapper;

import com.leiyuke.database.entity.User;

@Mapper
public interface UserMapper {
    List<User> getAll();
}

　　二、主要说明

　　1、tomcat使用的是apache-tomcat-9.0.0.M20.zip，解压后删除webapps中的所有目录及文件（必须）

　　2、修改配置文件context.xml，添加如下内容：

<Context>
    <!-- Default set of monitored resources. If one of these changes, the    -->
    <!-- web application will be reloaded.                                   -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
    <WatchedResource>${catalina.base}/conf/web.xml</WatchedResource>
    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <!--
    <Manager pathname="" />
    -->
    <Resource
    name="test-jndi"
    auth="Container"
    type="javax.sql.DataSource"
    factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
    driverClassName="com.mysql.cj.jdbc.Driver"
    url="jdbc:mysql://192.168.7.105:3306/sltest?autoReconnect=true&amp;serverTimezone=UTC&amp;characterEncoding=utf-8"
    username="root"
    password="123456"
    maxWaitMillis="100000"
    />
</Context>

　　3、示例中使用的是mysql5.7

　　4、示例中依赖是mysql-connector-java-5.1.46.jar，在打包完的项目中需要替换为mysql-connector-java-8.0.18.jar，否则无法启动

　　5、如果不想在项目的lib中替换为mysql-connector-java-8.0.18.jar，可以直接将此jar放入tomcat的lib中