Atomikos官网无法访问，不过Maven中央库中具atomikos包。Atomikos集成Spring，Hibernate，Mybatis网上文章比较多，本文是通过JavaSE的方式借用Spring配置来测试Atomikos对JTA的实现。
下面做一件事，就是两（+）个数据库，在一个事务里对其分别对数据库操作验证操作的原子性，即要么两个数据库的操作都成功，要么都失败。
1.准备工作
1.1 Maven pom.xml中添加依赖包
atomikos:（目前最新版）
|
1
2
3
4
5
|
<
dependency
>
<
groupId
>com.atomikos</
groupId
>
<
artifactId
>transactions-jdbc</
artifactId
>
<
version
>3.9.3</
version
>
</
dependency
>
|
jar依赖图：
Postgresql数据库驱动:
|
1
2
3
4
5
|
<
dependency
>
<
groupId
>org.postgresql</
groupId
>
<
artifactId
>postgresql</
artifactId
>
<
version
>9.2-1004-jdbc4</
version
>
</
dependency
>
|
注:文中使用的是Postgresql V9.2
javax.transaction.transaction-api.1.1:
|
1
2
3
4
5
6
7
8
|
<!-- Include in javaee-api -->
<!--
<dependency>
<groupId>javax.transaction</groupId>
<artifactId>transaction-api</artifactId>
<version>1.1</version>
</dependency>
-->
|
|
1
2
3
4
5
6
7
|
<!-- JavaEE -->
<!-- javaee-api包含了JavaEE规范中的api,如servlet-api,persistence-api, transaction-api等 -->
<
dependency
>
<
groupId
>javax</
groupId
>
<
artifactId
>javaee-api</
artifactId
>
<
version
>7.0</
version
>
</
dependency
>
|
注：根据需要选择其一即可。
Spring,Junit依赖这里省略。
1.2 创建数据库以及表
数据库分别是:javaee,tomdb
2.在项目中添加配置文件
spring-jta.xml 和transaction.properties（模版见文中附件）文件，spring-jta.xml在src/main/resources/integration下，transaction.properties在src/main/resources/下。
2.1在spring-jta.xml中配置两个XADataSource:
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
<!-- 使用分布式事务时设置Postgresql的max_prepared_transactions为大于0的值,该值默认是0 -->
<!-- 数据库A -->
<
bean
id
=
"a"
class
=
"com.atomikos.jdbc.AtomikosDataSourceBean"
init-method
=
"init"
destroy-method
=
"close"
>
<
property
name
=
"uniqueResourceName"
value
=
"pg/a"
/>
<
property
name
=
"xaDataSourceClassName"
value
=
"org.postgresql.xa.PGXADataSource"
/>
<
property
name
=
"xaProperties"
>
<
props
>
<
prop
key
=
"user"
>postgres</
prop
>
<
prop
key
=
"password"
>postgres</
prop
>
<
prop
key
=
"serverName"
>localhost</
prop
>
<
prop
key
=
"portNumber"
>5432</
prop
>
<
prop
key
=
"databaseName"
>tomdb</
prop
>
</
props
>
</
property
>
<
property
name
=
"poolSize"
value
=
"10"
/>
<
property
name
=
"reapTimeout"
value
=
"20000"
/>
</
bean
>
<
bean
id
=
"b"
class
=
"com.atomikos.jdbc.AtomikosDataSourceBean"
init-method
=
"init"
destroy-method
=
"close"
>
<
property
name
=
"uniqueResourceName"
value
=
"pg/b"
/>
<
property
name
=
"xaDataSourceClassName"
value
=
"org.postgresql.xa.PGXADataSource"
/>
<
property
name
=
"xaProperties"
>
<
props
>
<
prop
key
=
"user"
>postgres</
prop
>
<
prop
key
=
"password"
>postgres</
prop
>
<
prop
key
=
"serverName"
>localhost</
prop
>
<
prop
key
=
"portNumber"
>5432</
prop
>
<
prop
key
=
"databaseName"
>javaee</
prop
>
</
props
>
</
property
>
<
property
name
=
"poolSize"
value
=
"10"
/>
<
property
name
=
"reapTimeout"
value
=
"20000"
/>
</
bean
>
|
说明:
Postgresql的max_prepared_transactions参数值默认是0，要开启XA需要设置该值至少和max_connections参数值一样大，该参数在PostgreSQL\9.3\data\postgresql.conf文件中。
PGXADataSource的父类BaseDataSource没有url属性，可需要分别设置serverName,portNumber,databaseName等属性。不同的数据库驱动有不同的实现方法。
2.2 配置事务管理对象和UserTransaction接口实现
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
|
<!-- atomikos事务管理 -->
<
bean
id
=
"atomikosUserTransactionManager"
class
=
"com.atomikos.icatch.jta.UserTransactionManager"
init-method
=
"init"
destroy-method
=
"close"
>
<
description
>UserTransactionManager</
description
>
<
property
name
=
"forceShutdown"
value
=
"true"
/>
</
bean
>
<
bean
id
=
"atomikosUserTransaction"
class
=
"com.atomikos.icatch.jta.UserTransactionImp"
>
<
property
name
=
"transactionTimeout"
value
=
"300"
/>
</
bean
>
<
bean
id
=
"transactionManager"
class
=
"org.springframework.transaction.jta.JtaTransactionManager"
>
<
property
name
=
"transactionManager"
ref
=
"atomikosUserTransactionManager"
></
property
>
</
bean
>
|
上面三个Bean可以独立使用来进行事务控制，具体看下面3。
3. 编写测试
3.1 使用atomikosUserTransactionManager对象测试（TestAtomikos1.java）
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
package
secondriver.springsubway.example.jta;
import
java.sql.Connection;
import
java.sql.SQLException;
import
javax.transaction.HeuristicMixedException;
import
javax.transaction.HeuristicRollbackException;
import
javax.transaction.NotSupportedException;
import
javax.transaction.RollbackException;
import
javax.transaction.SystemException;
import
org.junit.BeforeClass;
import
org.junit.Test;
import
org.springframework.context.ApplicationContext;
import
org.springframework.context.support.ClassPathXmlApplicationContext;
import
com.atomikos.icatch.jta.UserTransactionManager;
import
com.atomikos.jdbc.AtomikosDataSourceBean;
public
class
TestAtomikos1 {
public
static
ApplicationContext ctx;
@BeforeClass
public
static
void
beforeClass() {
ctx =
new
ClassPathXmlApplicationContext(
"classpath:integration/spring-jta.xml"
);
}
public
static
void
afterClass() {
ctx =
null
;
}
@Test
public
void
test1() {
exe(
"abc"
,
"abc"
);
}
@Test
public
void
test2() {
exe(
"123="
,
"123"
);
}
public
void
exe(String av, String bv) {
AtomikosDataSourceBean adsA = (AtomikosDataSourceBean) ctx.getBean(
"a"
);
AtomikosDataSourceBean adsB = (AtomikosDataSourceBean) ctx.getBean(
"b"
);
Connection connA;
Connection connB;
UserTransactionManager utm = (UserTransactionManager) ctx
.getBean(
"atomikosUserTransactionManager"
);
try
{
utm.begin();
connA = adsA.getConnection();
connB = adsB.getConnection();
connA.prepareStatement(
"insert into jta_temp (value) values('"
+ av +
"')"
)
.execute();
connB.prepareStatement(
"insert into jta_temp (value) values('"
+ bv +
"')"
)
.execute();
utm.commit();
}
catch
(SQLException | NotSupportedException | SystemException
| SecurityException | IllegalStateException | RollbackException
| HeuristicMixedException | HeuristicRollbackException e) {
e.printStackTrace();
try
{
utm.rollback();
}
catch
(IllegalStateException | SecurityException
| SystemException e1) {
e1.printStackTrace();
}
}
}
}
|
3.2使用Spring的JtaUserTransactionManager对象测试（TestAtomikos2.java 修改TestAtomikos1.java中的exe方法即可）
|
1
2
3
4
5
6
7
8
9
|
@Test
public
void
test1() {
exe(
"abc"
,
"abc"
);
}
@Test
public
void
test2() {
exe(
"123="
,
"123"
);
}
|
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
|
public
void
exe(String av, String bv) {
TransactionFactory txm = (TransactionFactory) ctx
.getBean(
"transactionManager"
);
JdbcTemplate a = (JdbcTemplate) ctx.getBean(
"jdbcTemplateA"
);
JdbcTemplate b = (JdbcTemplate) ctx.getBean(
"jdbcTemplateB"
);
Transaction tx =
null
;
try
{
tx = txm.createTransaction(
"tx-name-define"
,
10000
);
a.update(
"insert into jta_temp (value) values('"
+ av +
"')"
);
b.update(
"insert into jta_temp (value) values('"
+ bv +
"')"
);
tx.commit();
}
catch
(NotSupportedException | SystemException | SecurityException
| RollbackException | HeuristicMixedException
| HeuristicRollbackException e) {
e.printStackTrace();
if
(tx!=
null
){
try
{
tx.rollback();
}
catch
(IllegalStateException | SystemException e1) {
e1.printStackTrace();
}
}
}
}
|
3.3使用atomikosUserTransaction Bean对象进行测试（TestAtomikos3.java 修改TestAtomikos1.java中的exe方法即可）
|
1
2
3
4
5
6
7
8
9
|
@Test
public
void
test1() {
exe(
"abc"
,
"abc"
);
}
@Test
public
void
test2() {
exe(
"123"
,
"123="
);
}
|
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
public
void
exe(String av, String bv) {
AtomikosDataSourceBean adsA = (AtomikosDataSourceBean) ctx.getBean(
"a"
);
AtomikosDataSourceBean adsB = (AtomikosDataSourceBean) ctx.getBean(
"b"
);
Connection connA;
Connection connB;
UserTransaction utx = (UserTransaction) ctx
.getBean(
"atomikosUserTransaction"
);
try
{
utx.begin();
connA = adsA.getConnection();
connB = adsB.getConnection();
connA.prepareStatement(
"insert into jta_temp (value) values('"
+ av +
"')"
)
.execute();
connB.prepareStatement(
"insert into jta_temp (value) values('"
+ bv +
"')"
)
.execute();
utx.commit();
}
catch
(SQLException | NotSupportedException | SystemException
| SecurityException | IllegalStateException | RollbackException
| HeuristicMixedException | HeuristicRollbackException e) {
e.printStackTrace();
try
{
utx.rollback();
}
catch
(IllegalStateException | SecurityException
| SystemException e1) {
e1.printStackTrace();
}
}
}
|
使用上述三种UserTransaction进行测试，其中test1方法是成功执行，test2方法是执行失败的（因为插入的值长度超过的字段长度限制）。通过分析之后，如果分布式事物控制正确，那么数据库中写入的值对于两张不同的表而言，是没有数字值被写入的。如图所示：
在测试过程中，经过对比确实达到了分布式事务控制的效果。
整个操作的架构图如下（摘自Atomikos Blog）
关于JTA原理文章开始提到的那篇文章，写的很详细和清晰，可以细细阅读和理解。
本文转自 secondriver 51CTO博客，原文链接：http://blog.51cto.com/aiilive/1658102，如需转载请自行联系原作者
