redis在專案中的使用
1.匯入jedis和池子的jar包
https://mvnrepository.com/artifact/org.apache.commons/commons-pool2/2.3
https://mvnrepository.com/artifact/redis.clients/jedis/2.7.0
2.匯入工具類
package com.itheima.utils;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;public class JedisPoolUtils {
private static JedisPool pool = null;
static{
//載入配置檔案
InputStream in = JedisPoolUtils.class.getClassLoader().getResourceAsStream("redis.properties");
Properties pro = new Properties();
try {
pro.load(in);
} catch (IOException e) {
e.printStackTrace();
}
//獲得池子物件
JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setMaxIdle(Integer.parseInt(pro.get("redis.maxIdle").toString()));//最大閒置個數
poolConfig.setMinIdle(Integer.parseInt(pro.get("redis.minIdle").toString()));//最小閒置個數
poolConfig.setMaxTotal(Integer.parseInt(pro.get("redis.maxTotal").toString()));//最大連線數
pool = new JedisPool(poolConfig,pro.getProperty("redis.url") , Integer.parseInt(pro.get("redis.port").toString()));
}//獲得jedis資源的方法
public static Jedis getJedis(){
return pool.getResource();
}
public static void main(String[] args) {
Jedis jedis = getJedis();
System.out.println(jedis.get("xxx"));
}
}
3.匯入配置檔案
redis.maxIdle=30
redis.minIdle=10
redis.maxTotal=100
redis.url=localhost
redis.port=6379
4. 編寫程式碼
package com.itheima.web.servlet;
import java.io.IOException;
import java.util.List;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import com.google.gson.Gson;
import com.itheima.domain.Category;
import com.itheima.service.ProductService;
import com.itheima.utils.JedisPoolUtils;import redis.clients.jedis.Jedis;
public class CategoryListServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
ProductService service = new ProductService();
//先從快取中查詢categoryList 如果有直接使用 沒有在從資料庫中查詢 存到快取中
//1、獲得jedis物件 連線redis資料庫
Jedis jedis = JedisPoolUtils.getJedis();
String categoryListJson = jedis.get("categoryListJson");
//2、判斷categoryListJson是否為空
if(categoryListJson==null){
System.out.println("快取沒有資料 查詢資料庫");
//準備分類資料
List<Category> categoryList = service.findAllCategory();
Gson gson = new Gson();
categoryListJson = gson.toJson(categoryList);
jedis.set("categoryListJson", categoryListJson);
}
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write(categoryListJson);
}protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}