sharding-jdbc实现原理——分库分表代码实战
Sharding-JDBC简介
Sharding-JDBC是当当应用框架ddframe中，从关系型数据库模块dd-rdb中分离出来的数据库水平分片框架，实现透明化数据库分库分表访问。Sharding-JDBC是继dubbox和elastic-job之后，ddframe系列开源的第3个项目。
实现原理
前文已介绍了Sharding-JDBC是实现了JDBC协议的jar文件。基于JDBC协议的实现与基于MySQL等数据库协议实现的中间层略有差别。
无论使用哪种架构，核心逻辑均极为相似，除了协议实现层不同（JDBC或数据库协议），都会分为分片规则配置、SQL解析、SQL改写、SQL路由、SQL执行以及结果归并等模块。
Sharding-JDBC的整体架构图参见图1。
图1 Sharding-JDBC的整体架构图
分库分表实战
接下来，我们就利用sharding-jdbc进行数据库的分库分表操作。
1、创建数据库
首先我们创建相应的数据库
create database sharding_0;
create database sharding_1;
这样我们就创建了两个数据库sharding_0和sharding_1;
接下来我们在两个库中创建相应的数据表，在两个库中分别进行如下SQL:
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for t_student_00
-- ----------------------------
DROP TABLE IF EXISTS `t_student_00`;
CREATE TABLE `t_student_00` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`student_id` int(11) NOT NULL,
`name` varchar(255) NOT NULL,
`age` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Table structure for t_student_01
-- ----------------------------
DROP TABLE IF EXISTS `t_student_01`;
CREATE TABLE `t_student_01` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`student_id` int(11) NOT NULL,
`name` varchar(255) NOT NULL,
`age` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Table structure for t_user_00
-- ----------------------------
DROP TABLE IF EXISTS `t_user_00`;
CREATE TABLE `t_user_00` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) NOT NULL,
`name` varchar(255) NOT NULL,
`age` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Table structure for t_user_01
-- ----------------------------
DROP TABLE IF EXISTS `t_user_01`;
CREATE TABLE `t_user_01` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) NOT NULL,
`name` varchar(255) NOT NULL,
`age` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Table structure for t_user_02
-- ----------------------------
DROP TABLE IF EXISTS `t_user_02`;
CREATE TABLE `t_user_02` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) NOT NULL,
`name` varchar(255) NOT NULL,
`age` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
这样，我们的数据库就准备好了。
2、创建项目
接下来，我们就创建一个Maven项目，项目结构如下：
3、配置pom.xml
4、创建数据库映射类
这里，我们创建两个数据库映射类：User类和Student类。
4-1、User类
package com.lyz.sharding.entity;
import java.io.Serializable;
/**
* 用户类
* @author liuyazhuang
*
*/
public class User implements Serializable {
private static final long serialVersionUID = 1L;
private Integer id;
private Integer userId;
private String name;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "User [id=" + id + ", userId=" + userId + ", name=" + name + ", age=" + age + "]";
}
}
4-2、Student类
package com.lyz.sharding.entity;
import java.io.Serializable;
/**
* 学生类
* @author liuyazhuang
*
*/
public class Student implements Serializable {
private static final long serialVersionUID = 8920597824668331209L;
private Integer id;
private Integer studentId;
private String name;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getStudentId() {
return studentId;
}
public void setStudentId(Integer studentId) {
this.studentId = studentId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Student [id=" + id + ", studentId=" + studentId + ", name=" + name + ", age=" + age + "]";
}
}
5、创建Mapper类
5-1、UserMapper类
package com.lyz.sharding.mapper;
import java.util.List;
import com.lyz.sharding.entity.User;
/**
* 处理用户的数据操作接口
* @author liuyazhuang
*
*/
public interface UserMapper {
Integer insert(User u);
List
List
}
5-2、StudentMapper类
package com.lyz.sharding.mapper;
import java.util.List;
import com.lyz.sharding.entity.Student;
/**
* 处理学生的数据操作接口
* @author liuyazhuang
*
*/
public interface StudentMapper {
Integer insert(Student s);
List
List
}
6、创建service类
6-1、UserService类
package com.lyz.sharding.service;
import java.util.List;
import com.lyz.sharding.entity.User;
/**
* 处理用户的Service
* @author liuyazhuang
*
*/
public interface UserService {
public boolean insert(User u);
public List
public List
public void transactionTestSucess();
public void transactionTestFailure() throws IllegalAccessException;
}
6-2、StudentService类
package com.lyz.sharding.service;
import com.lyz.sharding.entity.Student;
/**
* 处理学生的service
* @author liuyazhuang
*
*/
public interface StudentService {
boolean insert(Student student);
}
7、创建service的实现类
7-1、UserServiceImpl类
package com.lyz.sharding.service.impl;
import java.util.List;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import com.lyz.sharding.entity.Student;
import com.lyz.sharding.entity.User;
import com.lyz.sharding.mapper.StudentMapper;
import com.lyz.sharding.mapper.UserMapper;
import com.lyz.sharding.service.UserService;
@Service
@Transactional
public class UserServiceImpl implements UserService {
@Resource
public UserMapper userMapper;
@Resource
public StudentMapper studentMapper;
public boolean insert(User u) {
return userMapper.insert(u) > 0 ? true :false;
}
public List
return userMapper.findAll();
}
public List
return userMapper.findByUserIds(ids);
}
@Transactional(propagation=Propagation.REQUIRED)
public void transactionTestSucess() {
User u = new User();
u.setUserId(13);
u.setAge(25);
u.setName("war3 1.27");
userMapper.insert(u);
Student student = new Student();
student.setStudentId(21);
student.setAge(21);
student.setName("hehe");
studentMapper.insert(student);
}
@Transactional(propagation=Propagation.REQUIRED)
public void transactionTestFailure() throws IllegalAccessException {
User u = new User();
u.setUserId(13);
u.setAge(25);
u.setName("war3 1.27 good");
userMapper.insert(u);
Student student = new Student();
student.setStudentId(21);
student.setAge(21);
student.setName("hehe1");
studentMapper.insert(student);
throw new IllegalAccessException();
}
}
7-2、StudentServiceImpl类
package com.lyz.sharding.service.impl;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import com.lyz.sharding.entity.Student;
import com.lyz.sharding.mapper.StudentMapper;
import com.lyz.sharding.service.StudentService;
@Service
public class StudentServiceImpl implements StudentService{
@Resource
public StudentMapper studentMapper;
public boolean insert(Student student) {
return studentMapper.insert(student) > 0 ? true : false;
}
}
8、创建分库逻辑
8-1、User分库逻辑UserSingleKeyDatabaseShardingAlgorithm类
package com.lyz.sharding.algorithm;
import java.util.Collection;
import java.util.LinkedHashSet;
import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.database.SingleKeyDatabaseShardingAlgorithm;
import com.google.common.collect.Range;
/**
* user表分库的逻辑函数
* @author liuyazhuang
*
*/
public class UserSingleKeyDatabaseShardingAlgorithm implements SingleKeyDatabaseShardingAlgorithm
/**
* sql 中关键字 匹配符为 =的时候，表的路由函数
*/
public String doEqualSharding(Collection
for (String each : availableTargetNames) {
if (each.endsWith(shardingValue.getValue() % 2 + "")) {
return each;
}
}
throw new IllegalArgumentException();
}
/**
* sql 中关键字 匹配符为 in 的时候，表的路由函数
*/
public Collection
Collection
for (Integer value : shardingValue.getValues()) {
for (String tableName : availableTargetNames) {
if (tableName.endsWith(value % 2 + "")) {
result.add(tableName);
}
}
}
return result;
}
/**
* sql 中关键字 匹配符为 between的时候，表的路由函数
*/
public Collection
ShardingValue
Collection
Range
for (Integer i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
for (String each : availableTargetNames) {
if (each.endsWith(i % 2 + "")) {
result.add(each);
}
}
}
return result;
}
}
8-2、Student分库逻辑StudentSingleKeyDatabaseShardingAlgorithm
package com.lyz.sharding.algorithm;
import java.util.Collection;
import java.util.LinkedHashSet;
import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.database.SingleKeyDatabaseShardingAlgorithm;
import com.google.common.collect.Range;
/**
* user表分库的逻辑函数
* @author liuyazhuang
*
*/
public class StudentSingleKeyDatabaseShardingAlgorithm implements SingleKeyDatabaseShardingAlgorithm
/**
* sql 中关键字 匹配符为 =的时候，表的路由函数
*/
@Override
public String doEqualSharding(Collection
for (String each : availableTargetNames) {
if (each.endsWith(shardingValue.getValue() % 2 + "")) {
return each;
}
}
throw new IllegalArgumentException();
}
/**
* sql 中关键字 匹配符为 in 的时候，表的路由函数
*/
@Override
public Collection
Collection
for (Integer value : shardingValue.getValues()) {
for (String tableName : availableTargetNames) {
if (tableName.endsWith(value % 2 + "")) {
result.add(tableName);
}
}
}
return result;
}
/**
* sql 中关键字 匹配符为 between的时候，表的路由函数
*/
@Override
public Collection
ShardingValue
Collection
Range
for (Integer i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
for (String each : availableTargetNames) {
if (each.endsWith(i % 2 + "")) {
result.add(each);
}
}
}
return result;
}
}
9、创建分表逻辑
9-1、User分表逻辑UserSingleKeyTableShardingAlgorithm
package com.lyz.sharding.algorithm;
import java.util.Collection;
import java.util.LinkedHashSet;
import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.SingleKeyTableShardingAlgorithm;
import com.google.common.collect.Range;
/**
* 因为t_student实际表在每个库中只有3个，所以 %3
* @author iuyazhuang
*
*/
public class UserSingleKeyTableShardingAlgorithm implements SingleKeyTableShardingAlgorithm
/**
* sql 中 = 操作时，table的映射
*/
public String doEqualSharding(Collection
for (String each : tableNames) {
if (each.endsWith(("0".concat(String.valueOf(shardingValue.getValue() % 3))))) {
return each;
}
}
throw new IllegalArgumentException();
}
/**
* sql 中 in 操作时，table的映射
*/
public Collection
Collection
for (Integer value : shardingValue.getValues()) {
for (String tableName : tableNames) {
if (tableName.endsWith(("0".concat(String.valueOf(value % 3))))) {
result.add(tableName);
}
}
}
return result;
}
/**
* sql 中 between 操作时，table的映射
*/
public Collection
ShardingValue
Collection
Range
for (Integer i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
for (String each : tableNames) {
if (each.endsWith(("0".concat(String.valueOf(i % 3))))) {
result.add(each);
}
}
}
return result;
}
}
9-2、创建Student分表逻辑StudentSingleKeyTableShardingAlgorithm
package com.lyz.sharding.algorithm;
import java.util.Collection;
import java.util.LinkedHashSet;
import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.SingleKeyTableShardingAlgorithm;
import com.google.common.collect.Range;
/**
* 因为t_student实际表在每个库中只有2个，所以 %2
* @author iuyazhuang
*
*/
public class StudentSingleKeyTableShardingAlgorithm implements SingleKeyTableShardingAlgorithm
/**
* sql 中 = 操作时，table的映射
*/
public String doEqualSharding(Collection
for (String each : tableNames) {
if (each.endsWith("0".concat(String.valueOf(shardingValue.getValue() % 2)))) {
return each;
}
}
throw new IllegalArgumentException();
}
/**
* sql 中 in 操作时，table的映射
*/
public Collection
Collection
for (Integer value : shardingValue.getValues()) {
for (String tableName : tableNames) {
if (tableName.endsWith("0".concat(String.valueOf(value % 2)))) {
result.add(tableName);
}
}
}
return result;
}
/**
* sql 中 between 操作时，table的映射
*/
public Collection
ShardingValue
Collection
Range
for (Integer i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
for (String each : tableNames) {
if (each.endsWith("0".concat(String.valueOf(i % 2)))) {
result.add(each);
}
}
}
return result;
}
}
10、创建Mapper.xml
10-1、创建UserMapper.xml
insert into t_user (user_id,name,age) values (#{userId},#{name},#{age})
id,user_id,name,age
10-2、创建StudentMapper.xml
insert into t_student (student_id,name,age) values (#{studentId},#{name},#{age})
id,student_id,name,age
11、创建jdbc_dev.properties
jdbc_driver0 = com.mysql.jdbc.Driver
jdbc_url0 = jdbc:mysql://localhost:3306/sharding_0?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
jdbc_username0 = root
jdbc_password0 = root
jdbc_driver1 = com.mysql.jdbc.Driver
jdbc_url1 = jdbc:mysql://localhost:3306/sharding_1?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
jdbc_username1 = root
jdbc_password1 = root
validationQuery=SELECT 1
12、创建spring配置文件
12-1、spring-database.xml
xmlns:mybatis-spring="http://mybatis.org/schema/mybatis-spring"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring-1.2.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
12-2、spring-sharding.xml
xmlns:mybatis-spring="http://mybatis.org/schema/mybatis-spring"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring-1.2.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
13、创建log4j.xml
14、创建测试类ShardingJdbcMybatisTest
package com.lyz.sharding.test;
import java.util.Arrays;
import java.util.List;
import javax.annotation.Resource;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.lyz.sharding.entity.Student;
import com.lyz.sharding.entity.User;
import com.lyz.sharding.service.StudentService;
import com.lyz.sharding.service.UserService;
/**
* 测试分库分表规则
* @author liuyazhuang
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath*:config/spring/spring-database.xml", "classpath*:config/spring/spring-sharding.xml" })
public class ShardingJdbcMybatisTest {
@Resource
public UserService userService;
@Resource
public StudentService studentService;
@Test
public void testUserInsert() {
User u = new User();
u.setUserId(11);
u.setAge(25);
u.setName("github");
Assert.assertEquals(userService.insert(u), true);
}
@Test
public void testStudentInsert() {
Student student = new Student();
student.setStudentId(21);
student.setAge(21);
student.setName("hehe");
Assert.assertEquals(studentService.insert(student), true);
}
@Test
public void testFindAll(){
List
if(null != users && !users.isEmpty()){
for(User u :users){
System.out.println(u);
}
}
}
@Test
public void testSQLIN(){
List
if(null != users && !users.isEmpty()){
for(User u :users){
System.out.println(u);
}
}
}
@Test
public void testTransactionTestSucess(){
userService.transactionTestSucess();
}
@Test(expected = IllegalAccessException.class)
public void testTransactionTestFailure() throws IllegalAccessException{
userService.transactionTestFailure();
}
}
三、测试
我们进行ShardingJdbcMybatisTest类，查看数据表数据，即可看到我们的程序利用sharding-jdbc实现了分库分表操作。
四、温馨提示
大家可以到链接http://download.csdn.net/download/l1028386804/10258290下载完整的sharding-jdbc分库分表实例源代码