spring-state-machine持久化

天底下只有一个方法可以影响人，就是提到他们的需要，并且让他们知道怎么去获得。——卡耐基

文档如下：

https://docs.spring.io/spring-statemachine/docs/current/reference/#statemachine-examples-datapersist

代码示例如下：

https://github.com/spring-projects/spring-statemachine/tree/main/spring-statemachine-samples/persist

状态机持久化主要解决服务端重启后会话丢失问题

代码语言：javascript复制

/*
 * Copyright 2015-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package demo.persist;

import static org.assertj.core.api.Assertions.assertThat;
import static org.springframework.statemachine.TestUtils.doStartAndAssert;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.statemachine.StateMachine;
import org.springframework.statemachine.listener.StateMachineListenerAdapter;
import org.springframework.statemachine.state.State;
import org.springframework.statemachine.transition.Transition;
import org.springframework.test.annotation.DirtiesContext;
import org.springframework.test.annotation.DirtiesContext.ClassMode;
import org.springframework.test.context.junit.jupiter.SpringExtension;

import demo.CommonConfiguration;

@ExtendWith(SpringExtension.class)
@DirtiesContext(classMode=ClassMode.AFTER_EACH_TEST_METHOD)
@SpringBootTest(classes = { CommonConfiguration.class, Application.class, StateMachineCommands.class })
public class PersistTests {

	@Autowired
	private StateMachineCommands commands;

	@Autowired
	private StateMachine<String, String> machine;

	@Autowired
	private Persist persist;

	@Test
	public void testNotStarted() throws Exception {
		assertThat(commands.state()).isEqualTo("No state");
	}

	@Test
	public void testInitialState() throws Exception {
		TestListener listener = new TestListener();
		machine.addStateListener(listener);
		doStartAndAssert(machine);
		assertThat(listener.stateChangedLatch.await(3, TimeUnit.SECONDS)).isTrue();
		assertThat(listener.stateEnteredLatch.await(3, TimeUnit.SECONDS)).isTrue();
		assertThat(machine.getState().getIds()).containsExactly("PLACED");
		assertThat(listener.statesEntered).hasSize(1);
		assertThat(listener.statesEntered.get(0).getId()).isEqualTo("PLACED");
		assertThat(listener.statesExited).isEmpty();
	}

	@Test
	public void testInitialDbList() {
		// dataOrder [id=1, state=PLACED]Order [id=2, state=PROCESSING]Order [id=3, state=SENT]Order [id=4, state=DELIVERED]
		assertThat(persist.listDbEntries()).contains("PLACED");
	}

	@Test
	public void testUpdate1() {
		persist.change(1, "PROCESS");
		assertThat(persist.listDbEntries()).contains("id=1, state=PROCESSING");
	}

	@Test
	public void testUpdate2() {
		persist.change(2, "SEND");
		assertThat(persist.listDbEntries()).contains("id=2, state=SENT");
	}

	private static class TestListener extends StateMachineListenerAdapter<String, String> {

		volatile CountDownLatch stateChangedLatch = new CountDownLatch(1);
		volatile CountDownLatch stateEnteredLatch = new CountDownLatch(1);
		volatile CountDownLatch stateExitedLatch = new CountDownLatch(0);
		volatile CountDownLatch transitionLatch = new CountDownLatch(0);
		volatile List<Transition<String, String>> transitions = new ArrayList<Transition<String, String>>();
		List<State<String, String>> statesEntered = new ArrayList<State<String, String>>();
		List<State<String, String>> statesExited = new ArrayList<State<String, String>>();

		@Override
		public void stateChanged(State<String, String> from, State<String, String> to) {
			stateChangedLatch.countDown();
		}

		@Override
		public void stateEntered(State<String, String> state) {
			statesEntered.add(state);
			stateEnteredLatch.countDown();
		}

		@Override
		public void stateExited(State<String, String> state) {
			statesExited.add(state);
			stateExitedLatch.countDown();
		}

		@Override
		public void transition(Transition<String, String> transition) {
			transitions.add(transition);
			transitionLatch.countDown();
		}

	}

}

spring import public state string

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