CentOS 網路介面配置檔案配置示例及詳解
阿新 • • 發佈:2020-12-22
前臺程式碼
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script src="js/jquery-3.3.1.min.js"></script> <script> $(function () { //傳送ajaxqingq $.get("provinceServlet",{},function (data) { //[{"id":1,"name":"北京"},{"id":2,"name":"上海"},{"id":3,"name":"廣州"},{"id":4,"name":"陝西"}] //1.獲取select var property=$("#province") //2.遍歷json陣列 $(data).each(function () { //3.建立<option> var option="<option name='"+this.id+"'>"+this.name+"</option>" //4.呼叫select的append追加option property.append(option); }); }); }) </script> </head> <body> <select id="province"> <option>---請選擇---</option> </select> </body> </html>
實體類程式碼
package cn.jztd.domain; public class Province { private int id; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
package cn.jztd.dao.impl; import cn.jztd.domain.Province; import java.util.List; public interface ProvinceDao { public List<Province> findAll(); }dao層實現介面程式碼
package cn.jztd.dao.impl; import cn.jztd.domain.Province; import cn.jztd.utils.JDBCUtils; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.ResultSetExtractor; import java.util.List; public class ProvinceDaoimpl implements ProvinceDao { //1.宣告成員變數 jdbctemplement private JdbcTemplate template=new JdbcTemplate(JDBCUtils.getDataSource()); @Override public List<Province> findAll() { //1.定義sql String sql="select * from province"; //2.執行sql,查詢賦值到實體類 List<Province> list = template.query(sql, new BeanPropertyRowMapper<Province>(Province.class)); return list; } }
package cn.jztd.service.impl; import cn.jztd.domain.Province; import java.util.List; public interface ProcinceService { public List<Province> findAll(); public String faindojosn(); }serice實現介面程式碼
package cn.jztd.service.impl; import cn.jztd.dao.impl.ProvinceDaoimpl; import cn.jztd.domain.Province; import cn.jztd.redis.util.JediPoolUtils; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import redis.clients.jedis.Jedis; import java.util.List; public class ProcinceServiceimpl implements ProcinceService { ProvinceDaoimpl pr=new ProvinceDaoimpl(); @Override public List<Province> findAll() { return pr.findAll(); } @Override public String faindojosn() { //連線redis Jedis jedis= JediPoolUtils.getJed(); //查詢procince的值 String per=jedis.get("procince"); if(per==null||per.length()==0)//判斷該鍵在redis中存在嗎 { System.out.println("沒有查詢到資料"); //不存在查詢資料庫 List<Province> list = pr.findAll(); //序列化為json ObjectMapper mapper=new ObjectMapper(); try { per = mapper.writeValueAsString(list); jedis.set("procince",per); } catch (JsonProcessingException e) { e.printStackTrace(); } //把json新增到redis中 } else { System.out.println("查詢到資料"); } return per; } }
servlet程式碼
package cn.jztd.web.servlet; import cn.jztd.dao.impl.ProvinceDao; import cn.jztd.dao.impl.ProvinceDaoimpl; import cn.jztd.domain.Province; import cn.jztd.service.impl.ProcinceService; import cn.jztd.service.impl.ProcinceServiceimpl; import com.fasterxml.jackson.databind.ObjectMapper; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.util.List; @WebServlet("/provinceServlet") public class ProvinceServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1.呼叫查詢 ProcinceService provinceDao=new ProcinceServiceimpl(); /* List<Province> list = provinceDao.findAll(); //2.序列化list為json ObjectMapper objectMapper=new ObjectMapper(); String json = objectMapper.writeValueAsString(list); System.out.println(json);*/ //redis快取方式查詢 String json=provinceDao.faindojosn(); System.out.println(json); //3.響應格式 response.setContentType("application/json;charset=utf-8"); response.getWriter().write(json); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }