spring中使用@PostConstruct和@PreConstruct注解

1.@PostConstruct说明

被@PostConstruct修饰的方法会在服务器加载Servlet的时候运行，并且只会被服务器调用一次，类似于Serclet的inti()方法。被@PostConstruct修饰的方法会在构造函数之后，init()方法之前运行。

2.@PreDestroy说明

被@PreDestroy修饰的方法会在服务器卸载Servlet的时候运行，并且只会被服务器调用一次，类似于Servlet的destroy()方法。被@PreDestroy修饰的方法会在destroy()方法之后运行，在Servlet被彻底卸载之前。（详见下面的程序实践）

package com.yygx.flowinterface.service.impl;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import net.zoneland.uniflow.client.impl.SyncProcessServiceClient;
import net.zoneland.uniflow.client.impl.SyncTaskServiceClient;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Repository;

/**
 *
 * 流程引擎客户端工具类
 * @author wuhda
 *
 */
@Repository
public class FlowClientUtil {

	private final static Logger LOGGER = LoggerFactory.getLogger(FlowClientUtil.class);

	/**
	 * 流程类接口客户端
	 */
	private SyncProcessServiceClient processClient;

	/**
	 * 任务类接口客户端
	 */
	private SyncTaskServiceClient taskClient;

	@PostConstruct
	public void init() {
		// 接入系统的账号密码，在流程管理平台（UniflowAdminConsole）上配置
		String username = "ehr";
		String password = "password";

		// Uniflow的服务地址
		String endpoint = "http://172.16.92.50:10081/UniflowControlCenter/rest";

		// 构建流程类接口客户端
		processClient = new SyncProcessServiceClient(username, password);
		processClient.setServerAddress( endpoint + "/RestProcessService" );

		// 构建任务类接口客户端
		taskClient = new SyncTaskServiceClient(username, password);
		taskClient.setServerAddress( endpoint + "/RestTaskService" );
	}

	@PreDestroy
	public void close() {
		System.out.println("close client ...");
		// 应用结束是最好关闭客户端（内部有HttpClient的连接池）
		processClient.close();
		taskClient.close();
	}

	public SyncProcessServiceClient getProcessClient() {
		return processClient;
	}

	public void setProcessClient(SyncProcessServiceClient processClient) {
		this.processClient = processClient;
	}

	public SyncTaskServiceClient getTaskClient() {
		return taskClient;
	}

	public void setTaskClient(SyncTaskServiceClient taskClient) {
		this.taskClient = taskClient;
	}

}