在進(jìn)行多租戶架構(gòu)(Multi-tenancy)實現(xiàn)之前鞋诗，先了解一下相關(guān)的定義吧：
什么是多租戶
多租戶技術(shù)或稱多重租賃技術(shù)，簡稱SaaS井氢，是一種軟件架構(gòu)技術(shù)蟋滴，是實現(xiàn)如何在多用戶環(huán)境下（此處的多用戶一般是面向企業(yè)用戶）共用相同的系統(tǒng)或程序組件，并且可確保各用戶間數(shù)據(jù)的隔離性缤削。
簡單講：在一臺服務(wù)器上運行單個應(yīng)用實例拌屏，它為多個租戶（客戶）提供服務(wù)被廓。從定義中我們可以理解：多租戶是一種架構(gòu)蛛枚，目的是為了讓多用戶環(huán)境下使用同一套程序谅海，且保證用戶間數(shù)據(jù)隔離。那么重點就很淺顯易懂了蹦浦，多租戶的重點就是同一套程序下實現(xiàn)多用戶數(shù)據(jù)的隔離扭吁。
數(shù)據(jù)隔離方案
多租戶在數(shù)據(jù)存儲上存在三種主要的方案，分別是：
獨立數(shù)據(jù)庫
即一個租戶一個數(shù)據(jù)庫，這種方案的用戶數(shù)據(jù)隔離級別最高侥袜，安全性最好蝌诡，但成本較高。
優(yōu)點：為不同的租戶提供獨立的數(shù)據(jù)庫系馆，有助于簡化數(shù)據(jù)模型的擴(kuò)展設(shè)計送漠，滿足不同租戶的獨特需求顽照；如果出現(xiàn)故障由蘑，恢復(fù)數(shù)據(jù)比較簡單。
缺點：增多了數(shù)據(jù)庫的安裝數(shù)量代兵，隨之帶來維護(hù)成本和購置成本的增加尼酿。
共享數(shù)據(jù)庫，獨立 Schema
多個或所有租戶共享Database植影，但是每個租戶一個Schema（也可叫做一個user）裳擎。底層庫比如是：DB2、ORACLE等思币，一個數(shù)據(jù)庫下可以有多個SCHEMA鹿响。
優(yōu)點：為安全性要求較高的租戶提供了一定程度的邏輯數(shù)據(jù)隔離，并不是完全隔離谷饿；每個數(shù)據(jù)庫可支持更多的租戶數(shù)量惶我。
缺點：如果出現(xiàn)故障，數(shù)據(jù)恢復(fù)比較困難博投，因為恢復(fù)數(shù)據(jù)庫將牽涉到其他租戶的數(shù)據(jù)绸贡；
共享數(shù)據(jù)庫，共享 Schema毅哗，共享數(shù)據(jù)表
即租戶共享同一個Database听怕、同一個Schema，但在表中增加TenantID多租戶的數(shù)據(jù)字段虑绵。這是共享程度最高尿瞭、隔離級別最低的模式。
簡單來講翅睛，即每插入一條數(shù)據(jù)時都需要有一個客戶的標(biāo)識声搁。這樣才能在同一張表中區(qū)分出不同客戶的數(shù)據(jù)，這也是我們系統(tǒng)目前用到的(provider_id)
優(yōu)點：三種方案比較宏所，第三種方案的維護(hù)和購置成本最低酥艳，允許每個數(shù)據(jù)庫支持的租戶數(shù)量最多。
缺點：隔離級別最低爬骤，安全性最低充石，需要在設(shè)計開發(fā)時加大對安全的開發(fā)量；數(shù)據(jù)備份和恢復(fù)最困難霞玄，需要逐表逐條備份和還原骤铃。
利用MybatisPlus實現(xiàn)
這里我們選用了第三種方案（共享數(shù)據(jù)庫拉岁，共享 Schema，共享數(shù)據(jù)表）來實現(xiàn)惰爬，也就意味著喊暖，每個數(shù)據(jù)表都需要有一個租戶標(biāo)識(provider_id)
現(xiàn)在有數(shù)據(jù)庫表(user)如下：
image
將provider_id視為租戶ID，用來隔離租戶與租戶之間的數(shù)據(jù)撕瞧，如果要查詢當(dāng)前服務(wù)商的用戶陵叽，SQL大致如下：
SELECT * FROM user t WHERE t.name LIKE '%Tom%' AND t.provider_id = 1;
試想一下，除了一些系統(tǒng)共用的表以外丛版，其他租戶相關(guān)的表巩掺，我們都需要不厭其煩的加上AND t.provider_id = ?查詢條件，稍不注意就會導(dǎo)致數(shù)據(jù)越界页畦，數(shù)據(jù)安全問題讓人擔(dān)憂胖替。
好在有了MybatisPlus這個神器，可以極為方便的實現(xiàn)多租戶SQL解析器豫缨，官方文檔如下：
這里終于進(jìn)入了正題独令，開始搭建一個極為簡單的開發(fā)環(huán)境吧!
新建SpringBoot環(huán)境
POM文件如下，主要集成了MybatisPlus以及H2數(shù)據(jù)庫(方便測試)
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.wuwenze</groupId>
<artifactId>mybatis-plus-multi-tenancy</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>mybatis-plus-multi-tenancy</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</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>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>19.0</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.0.5</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus</artifactId>
<version>3.0.5</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
<version>3.0.5</version>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
數(shù)據(jù)源配置(application.yml)
spring:
datasource:
driver-class-name: org.h2.Driver
schema: classpath:db/schema.sql
data: classpath:db/data.sql
url: jdbc:h2:mem:test
username: root
password: test
logging:
level:
com.wuwenze.mybatisplusmultitenancy: debug
對應(yīng)的H2數(shù)據(jù)庫初始化schema文件
#schema.sql
DROP TABLE IF EXISTS user;
CREATE TABLE user
(
id BIGINT(20) NOT NULL COMMENT '主鍵',
provider_id BIGINT(20) NOT NULL COMMENT '服務(wù)商ID',
name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
PRIMARY KEY (id)
);
#data.sql
INSERT INTO user (id, provider_id, name) VALUES (1, 1, 'Tony老師');
INSERT INTO user (id, provider_id, name) VALUES (2, 1, 'William老師');
INSERT INTO user (id, provider_id, name) VALUES (3, 2, '路人甲');
INSERT INTO user (id, provider_id, name) VALUES (4, 2, '路人乙');
INSERT INTO user (id, provider_id, name) VALUES (5, 2, '路人丙');
INSERT INTO user (id, provider_id, name) VALUES (6, 2, '路人丁');
MybatisPlus Config
基礎(chǔ)環(huán)境搭建完成好芭，現(xiàn)在開始配置MybatisPlus多租戶相關(guān)的實現(xiàn)燃箭。
1) 核心配置：TenantSqlParser
@Configuration
@MapperScan("com.wuwenze.mybatisplusmultitenancy.mapper")
public class MybatisPlusConfig {
private static final String SYSTEM_TENANT_ID = "provider_id";
private static final List<String> IGNORE_TENANT_TABLES = Lists.newArrayList("provider");
@Autowired
private ApiContext apiContext;
@Bean
public PaginationInterceptor paginationInterceptor() {
PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
// SQL解析處理攔截：增加租戶處理回調(diào)。
TenantSqlParser tenantSqlParser = new TenantSqlParser()
.setTenantHandler(new TenantHandler() {
@Override
public Expression getTenantId() {
// 從當(dāng)前系統(tǒng)上下文中取出當(dāng)前請求的服務(wù)商ID栓撞，通過解析器注入到SQL中遍膜。
Long currentProviderId = apiContext.getCurrentProviderId();
if (null == currentProviderId) {
throw new RuntimeException("#1129 getCurrentProviderId error.");
}
return new LongValue(currentProviderId);
}
@Override
public String getTenantIdColumn() {
return SYSTEM_TENANT_ID;
}
@Override
public boolean doTableFilter(String tableName) {
// 忽略掉一些表：如租戶表（provider）本身不需要執(zhí)行這樣的處理。
return IGNORE_TENANT_TABLES.stream().anyMatch((e) -> e.equalsIgnoreCase(tableName));
}
});
paginationInterceptor.setSqlParserList(Lists.newArrayList(tenantSqlParser));
return paginationInterceptor;
}
@Bean(name = "performanceInterceptor")
public PerformanceInterceptor performanceInterceptor() {
return new PerformanceInterceptor();
}
}
2) ApiContext
@Component
public class ApiContext {
private static final String KEY_CURRENT_PROVIDER_ID = "KEY_CURRENT_PROVIDER_ID";
private static final Map<String, Object> mContext = Maps.newConcurrentMap();
public void setCurrentProviderId(Long providerId) {
mContext.put(KEY_CURRENT_PROVIDER_ID, providerId);
}
public Long getCurrentProviderId() {
return (Long) mContext.get(KEY_CURRENT_PROVIDER_ID);
}
}
3) Entity瓤湘、Mapper
@Data
@ToString
@Accessors(chain = true)
public class User {
private Long id;
private Long providerId;
private String name;
}
public interface UserMapper extends BaseMapper<User> {
}
image
單元測試
com.wuwenze.mybatisplusmultitenancy.MybatisPlusMultiTenancyApplicationTests
@Slf4j
@RunWith(SpringRunner.class)
@FixMethodOrder(MethodSorters.JVM)
@SpringBootTest(classes = MybatisPlusMultiTenancyApplication.class)
public class MybatisPlusMultiTenancyApplicationTests {
@Autowired
private ApiContext apiContext;
@Autowired
private UserMapper userMapper;
@Before
public void before() {
// 在上下文中設(shè)置當(dāng)前服務(wù)商的ID
apiContext.setCurrentProviderId(1L);
}
@Test
public void insert() {
User user = new User().setName("新來的Tom老師");
Assert.assertTrue(userMapper.insert(user) > 0);
user = userMapper.selectById(user.getId());
log.info("#insert user={}", user);
// 檢查插入的數(shù)據(jù)是否自動填充了租戶ID
Assert.assertEquals(apiContext.getCurrentProviderId(), user.getProviderId());
}
@Test
public void selectList() {
userMapper.selectList(null).forEach((e) -> {
log.info("#selectList, e={}", e);
// 驗證查詢的數(shù)據(jù)是否超出范圍
Assert.assertEquals(apiContext.getCurrentProviderId(), e.getProviderId());
});
}
}
運行結(jié)果
2018-11-29 21:07:14.262 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : Started MybatisPlusMultiTenancyApplicationTests in 2.629 seconds (JVM running for 3.904)
2018-11-29 21:07:14.554 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.insert : ==> Preparing: INSERT INTO user (id, name, provider_id) VALUES (?, ?, 1)
2018-11-29 21:07:14.577 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.insert : ==> Parameters: 1068129257418178562(Long), 新來的Tom老師(String)
2018-11-29 21:07:14.577 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.insert : <== Updates: 1
Time：0 ms - ID：com.wuwenze.mybatisplusmultitenancy.mapper.UserMapper.insert
Execute SQL：INSERT INTO user (id, name, provider_id) VALUES (?, ?, 1) {1: 1068129257418178562, 2: STRINGDECODE('\u65b0\u6765\u7684Tom\u8001\u5e08')}
2018-11-29 21:07:14.585 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectById : ==> Preparing: SELECT id, provider_id, name FROM user WHERE user.provider_id = 1 AND id = ?
2018-11-29 21:07:14.595 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectById : ==> Parameters: 1068129257418178562(Long)
2018-11-29 21:07:14.614 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectById : <== Total: 1
2018-11-29 21:07:14.615 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #insert user=User(id=1068129257418178562, providerId=1, name=新來的Tom老師)
Time：19 ms - ID：com.wuwenze.mybatisplusmultitenancy.mapper.UserMapper.selectById
Execute SQL：SELECT id, provider_id, name FROM user WHERE user.provider_id = 1 AND id = ? {1: 1068129257418178562}
2018-11-29 21:07:14.626 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectList : ==> Preparing: SELECT id, provider_id, name FROM user WHERE user.provider_id = 1
Time：0 ms - ID：com.wuwenze.mybatisplusmultitenancy.mapper.UserMapper.selectList
Execute SQL：SELECT id, provider_id, name FROM user WHERE user.provider_id = 1
2018-11-29 21:07:14.629 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectList : ==> Parameters:
2018-11-29 21:07:14.630 DEBUG 18688 --- [ main] c.w.m.mapper.UserMapper.selectList : <== Total: 3
2018-11-29 21:07:14.632 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #selectList, e=User(id=1, providerId=1, name=Tony老師)
2018-11-29 21:07:14.632 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #selectList, e=User(id=2, providerId=1, name=William老師)
2018-11-29 21:07:14.632 INFO 18688 --- [ main] .MybatisPlusMultiTenancyApplicationTests : #selectList, e=User(id=1068129257418178562, providerId=1, name=新來的Tom老師)
image
從打印的日志不難看出瓢颅，這個方案相當(dāng)完美，僅需簡單的配置弛说，讓開發(fā)者完全忽略了(provider_id)字段的存在挽懦，同時又最大程度的保證了數(shù)據(jù)的安全性，可謂是一舉兩得木人！
