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来源：杨尚川，
my.oschina.net/apdplat/blog/751206
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高可用: 服务多副本
高性能: 超时限制
负载均衡: 环形队列
已经实现的功能: 1. HTTP调用方式的搜索服务；2. REDIS访问
一句话说明白这个项目的原理: 后端有多个一模一样的搜索，还有多个一模一样的REDIS，中间层的业务逻辑不直接调用搜索和REDIS，而是通过这个组件来调用
在WEB项目中的使用方法
1. 编译依赖:
git clone https://github.com/ysc/high-availability.git
cd high-availability
mvn install
2. 在 pom.xml 中指定以下依赖:
org.apdplat.service
high-availability
1.0-SNAPSHOT
3. 在 src/main/resources 目录下新建目录 conf, 然后在 conf 目录下新建文件 conf.txt, 加入如下配置项:
#search api depends on these servers
search.api.server.urls=http://192.168.0.100:8080/search.jsp, http://192.168.0.101:8080/search.jsp
#timeout config to guarantee response time
search.api.timeout.seconds=1
#whether output status to log in every unavailable urls valid process
status.log.enabled=true
#unavailable schedule initial delay seconds
unavailable.schedule.initial.delay.seconds=60
#unavailable schedule period seconds
unavailable.schedule.period.seconds=60
#redis servers
redis.servers=192.168.0.102:6379:b01cbe1209a545a7cdb, 192.168.0.103:6379:b01cbe1209a545a7cdb
redis.pool.blockWhenExhausted=false
redis.pool.jmxEnabled=false
redis.pool.lifo=true
redis.pool.maxIdle=500
redis.pool.maxTotal=500
redis.pool.maxWaitMillis=500
redis.pool.minEvictableIdleTimeMillis=1800000
redis.pool.minIdle=0
redis.pool.numTestsPerEvictionRun=3
redis.pool.softMinEvictableIdleTimeMillis=1800000
redis.pool.testOnBorrow=true
redis.pool.testWhileIdle=true
redis.pool.timeBetweenEvictionRunsMillis=-1
redis.pool.readTimeoutMillis=2000
4. 在 web.xml 中配置一个监听器:
org.apdplat.data.visualization.container.HighAvailabilityListener
5. 监听器 HighAvailabilityListener.java 类的代码如下:
public class HighAvailabilityListener implements ServletContextListener {
private static final Logger LOGGER = LoggerFactory.getLogger(HighAvailabilityListener.class);
@Override
public void contextInitialized(ServletContextEvent sce) {
String conf = sce.getServletContext().getRealPath("/WEB-INF/classes/conf/");
LOGGER.info("启动搜索服务, 监控配置目录: {}", conf);
ConfWatcher.startWatch(conf);
sce.getServletContext().setAttribute("SearchAPI", new SearchAPIImpl());
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
LOGGER.info("停止搜索服务");
SearchAPI searchAPI = (SearchAPI)sce.getServletContext().getAttribute("SearchAPI");
if(searchAPI != null){
searchAPI.close();
}
LOGGER.info("停止监控配置目录");
ConfWatcher.stopWatch();
}
}
6. 在 jsp 中调用搜索服务:
SearchAPI searchAPI = (SearchAPI) application.getAttribute("SearchAPI");
if(searchAPI == null) {
out.println("搜索服务未启动");
return;
}
String keyword = request.getParameter("kw") == null ? "CCTV-1" : request.getParameter("kw");
int topN = 5;
try{
topN = Integer.parseInt(request.getParameter("topN"));
}catch (Exception e){
//
}
String result = null;
long start = System.currentTimeMillis();
result = searchAPI.search(keyword, topN);
String cost = Utils.getTimeDes(System.currentTimeMillis()-start);
// 如果想知道搜索服务的状态
String status = searchAPI.getStatus().replace("\n", "").replace("\t", " ");
7. 获取REDIS连接:
String DETECT_KEY = "redis_ha_detector";
Jedis jedis = null;
try{
jedis = JedisAPI.getInstance().getJedis();
// 如果所有REDIS服务都不可用, 则返回null
if(jedis != null) {
jedis.set(DETECT_KEY, String.valueOf(System.currentTimeMillis()));
System.out.println(jedis.get(DETECT_KEY));
System.out.println("REDIS服务状态:\n" + JedisAPI.getInstance().getStatus());
}
}finally {
if(jedis != null){
// 返回连接用完后必须要关闭, 调用close方法
jedis.close();
}
}
在非WEB项目中的使用方法
1. 编译依赖:
git clone https://github.com/ysc/high-availability.git
cd high-availability
mvn install
2. 在 pom.xml 中指定以下依赖:
org.apdplat.service
high-availability
1.0-SNAPSHOT
3. 新建目录 conf, 然后在 conf 目录下新建文件 conf.txt, 加入如下配置项:
#search api depends on these servers
search.api.server.urls=http://192.168.0.100:8080/search.jsp, http://192.168.0.101:8080/search.jsp
#timeout config to guarantee response time
search.api.timeout.seconds=1
#whether output status to log in every unavailable urls valid process
status.log.enabled=true
#unavailable schedule initial delay seconds
unavailable.schedule.initial.delay.seconds=60
#unavailable schedule period seconds
unavailable.schedule.period.seconds=60
#redis servers
redis.servers=192.168.0.102:6379:b01cbe1209a545a7cdb, 192.168.0.103:6379:b01cbe1209a545a7cdb
redis.pool.blockWhenExhausted=false
redis.pool.jmxEnabled=false
redis.pool.lifo=true
redis.pool.maxIdle=500
redis.pool.maxTotal=500
redis.pool.maxWaitMillis=500
redis.pool.minEvictableIdleTimeMillis=1800000
redis.pool.minIdle=0
redis.pool.numTestsPerEvictionRun=3
redis.pool.softMinEvictableIdleTimeMillis=1800000
redis.pool.testOnBorrow=true
redis.pool.testWhileIdle=true
redis.pool.timeBetweenEvictionRunsMillis=-1
redis.pool.readTimeoutMillis=2000
4. 将conf目录加入classpath:
java -cp conf:xxx-1.0-SNAPSHOT-jar-with-dependencies.jar
5. 启动搜索服务并监控配置目录的代码如下:
Path conf = Paths.get(ConfWatcher.class.getResource("/conf/").getPath());
LOGGER.info("启动搜索服务, 监控配置目录: {}", conf);
ConfWatcher.startWatch(conf);
SearchAPI searchAPI = new SearchAPIImpl();
6. 调用搜索服务:
String keyword = "CCTV-1";
int topN = 5;
String result = null;
long start = System.currentTimeMillis();
result = searchAPI.search(keyword, topN);
String cost = Utils.getTimeDes(System.currentTimeMillis()-start);
// 如果想知道搜索服务的状态
String status = searchAPI.getStatus();
7. 获取REDIS连接:
String DETECT_KEY = "redis_ha_detector";
Jedis jedis = null;
try{
jedis = JedisAPI.getInstance().getJedis();
// 如果所有REDIS服务都不可用, 则返回null
if(jedis != null) {
jedis.set(DETECT_KEY, String.valueOf(System.currentTimeMillis()));
System.out.println(jedis.get(DETECT_KEY));
System.out.println("REDIS服务状态:\n" + JedisAPI.getInstance().getStatus());
}
}finally {
if(jedis != null){
// 返回连接用完后必须要关闭, 调用close方法
jedis.close();
}
}
目录结构
├── README.md
├── pom.xml
└── src
└── main
├── java
│ └── org
│ └── apdplat
│ └── service
│ ├── api
│ │ ├── JedisAPI.java
│ │ └── SearchAPI.java
│ ├── configration
│ │ ├── ConfManager.java
│ │ ├── ConfTools.java
│ │ └── ConfWatcher.java
│ ├── impl
│ │ └── SearchAPIImpl.java
│ └── utils
│ └── TimeUtils.java
└── resources
└── conf
├── conf.production.txt
└── conf.txt
12 directories, 11 files
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