ssm+ehcache入门实战
ssm的整合不做介绍，主要介绍ehcache在项目中的应用
1、pom.xml引入ehcache jar包
net.sf.ehcache
ehcache-core
2.6.6
2、新建ehcache.xml文件并配置
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3、编写ehcache工具类EhCacheUtil2.java
package com.shp.util;
import java.net.URL;
import javax.annotation.PostConstruct;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
import net.sf.ehcache.Cache;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Element;
@Component
@Scope
public class EhCacheUtil2 {
private CacheManager manager;
private URL url;
@PostConstruct
public void init() {
url = getClass().getResource("/ehcache.xml");
manager = CacheManager.create(url);
}
public void put(String tableName, String key, Object value) {
Cache cache = manager.getCache(tableName);
if(cache == null) {
return;
}
Element element = new Element(key, value);
cache.put(element);
}
public Object get(String tableName, String key) throws Exception{
Cache cache = manager.getCache(tableName);
if(cache == null) {
return null;
}
Element element = cache.get(key);
return element == null ? null : element.getObjectValue();
}
public void remove(String tableName, String key) {
Cache cache = manager.getCache(tableName);
if(cache == null) {
return;
}
cache.remove(key);
}
public void clear(String tableName) {
Cache cache = manager.getCache(tableName);
if(cache == null) {
return;
}
cache.removeAll();
}
}
4、实体类Student.java
package com.shp.bean;
public class Student {
private int id;
private String name;
private int age;
private String gender;
private String grade;
public Student(int id, String name, int age, String gender, String grade) {
super();
this.id = id;
this.name = name;
this.age = age;
this.gender = gender;
this.grade = grade;
}
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;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", age=" + age + ", gender=" + gender + ", grade=" + grade + "]";
}
}
5、Dao层接口StudentDao.java
package com.shp.dao;
import java.util.List;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import com.shp.bean.Student;
public interface StudentDao {
String TABLE_NAME = "tbl_student";
void insertStudent(Student stu);
void deleteStudent(String name);
@Update({"Update",TABLE_NAME,"set age=#{student.age},grade=#{student.grade}","WHERE name=#{student.name}"})
void updateStudentByName(@Param("student") Student student);
@Select({"SELECT * FROM",TABLE_NAME,"WHERE name=#{name}"})
Student findStuByName(@Param("name") String name);
@Select({"SELECT * FROM",TABLE_NAME})
List QueryAll();
}
6、Service层接口StudentService.java
package com.shp.service;
import java.util.List;
import com.shp.bean.Student;
public interface StudentService {
void insertStudent(Student stu,String tableName);
void deleteStudent(String name,String tableName);
void updateStudentByName(Student stu,String tableName);
Student findStuByName(String name,String tableName);
List QueryAll();
}
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7、Service层接口实现StudentServiceImp.java
package com.shp.service.Imp;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.shp.bean.Student;
import com.shp.dao.StudentDao;
import com.shp.service.StudentService;
import com.shp.util.EhCacheUtil2;
@Service
public class StudentServiceImp implements StudentService{
@Autowired
private StudentDao stuDao;
@Autowired
private EhCacheUtil2 ehCacheUtil;
@Override
public void insertStudent(Student stu,String tableName) {
// TODO Auto-generated method stub
stuDao.insertStudent(stu);
}
@Override
public void deleteStudent(String name,String tableName) {
// TODO Auto-generated method stub
}
@Override
public void updateStudentByName(Student stu,String tableName) {
// TODO Auto-generated method stub
stuDao.updateStudentByName(stu);
String key=stu.getName();
ehCacheUtil.remove(tableName, key);
}
@SuppressWarnings("finally")
@Override
public Student findStuByName(String name,String tableName) {
// TODO Auto-generated method stub
Student student=null;
try {
student = (Student)ehCacheUtil.get(tableName, name);
if(student==null) {
student=stuDao.findStuByName(name);
ehCacheUtil.put(tableName, name, student);
}
}
catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally {
return student;
}
}
@Override
public List QueryAll() {
// TODO Auto-generated method stub
return stuDao.QueryAll();
}
}
8、测试TestController.java
package com.shp.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.shp.bean.Student;
import com.shp.dao.StudentDao;
import com.shp.service.Imp.StudentServiceImp;
@Controller
public class TestController {
@Autowired
private StudentDao sd;
@Autowired
private StudentServiceImp ssi;
@RequestMapping(value = "/test", method = RequestMethod.GET)
public String index(){
System.out.println("==测试去数据库中查找===");
long currentTime1= System.currentTimeMillis();
Student stu1=sd.findStuByName("小明");
long currentTime2= System.currentTimeMillis();
System.out.println("stu1="+stu1+"使用了"+(currentTime2-currentTime1)+"毫秒");
System.out.println("==测试第一次使用缓存方法查找==");
long currentTime3= System.currentTimeMillis();
Student stu2 = ssi.findStuByName("小明", "tbl_student");
long currentTime4= System.currentTimeMillis();
System.out.println("stu2="+stu2+"使用了"+(currentTime4-currentTime3)+"毫秒");
System.out.println("==测试第二次使用缓存方法查找==");
long currentTime5= System.currentTimeMillis();
Student stu3 = ssi.findStuByName("小明", "tbl_student");
long currentTime6= System.currentTimeMillis();
System.out.println("stu3="+stu3+"使用了"+(currentTime6-currentTime5)+"毫秒");
System.out.println("==测试update==begin==");
Student stu4=new Student(1, "小明", 20, "男", "大一");
sd.updateStudentByName(stu4);
System.out.println("==测试update去缓存中查找==");
Student stu5 = ssi.findStuByName("小明", "tbl_student");
System.out.println("stu5="+stu5);
System.out.println("==测试update去数据库中查找==");
Student stu6=sd.findStuByName("小明");
System.out.println("stu6="+stu6);
System.out.println("==测试update==finished==");
return "test";
}
}
9、测试结果
10、总结
从结果中很清晰的看出从缓存中查找数据要比访问数据库要快，需要注意的是update操作需要及时清除缓存，否则在缓存有效期内，查出的数据还是update之前的。同理，delete操作，也是如此。