模拟Hibernate一级缓存

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纯Java代码模拟Hibernate一级缓存原理，简单易懂。

标签： Java Ultra-Lite Persistence Hibernate

[1].[代码] Java代码模拟Hibernate一级缓存跳至 [1]

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importjava.util.ArrayList;
importjava.util.HashMap;
importjava.util.List;
importjava.util.Map;
 
publicclass LevelOneCache {
    //这个对象就是用来模拟hibernate一级缓存的
    privatestatic Map<Integer, Student> stus=newHashMap<Integer, Student>();
     
    publicstatic void main(String[] args) {
        getStudent(1);
        getStudent(1);
        getStudent(1);
        getStudent(2);
        getStudent(2);
    }
 
    publicstatic Student getStudent(Integer id){
        if(stus.containsKey(id)){
            System.out.println("从缓存中取数据");
            returnstus.get(id);
        }else{
            System.out.println("从数据库中取数据");
            Student s=MyDB.getStudentById(id);
            //将从数据库中取得的数据放入缓存
            stus.put(id, s);
            returns;
        }
    }
}
//模拟数据库
classMyDB{
    privatestatic List<Student> list=newArrayList<Student>();
    static{
        Student s1=newStudent();
        s1.setName("Name1");
        s1.setId(1);
        Student s2=newStudent();
        s2.setName("Name2");
        s2.setId(2);
        Student s3=newStudent();
        s3.setName("Name3");
        s3.setId(3);
        //初始化数据库
        list.add(s1);
        list.add(s2);
        list.add(s3);
    }
    //数据库中提供公共的查询方法
    publicstatic Student getStudentById(Integer id){
        for(Student s:list){
            if(s.getId().equals(id)){
                returns;
            }
        }
        //查询不到则返回空
        returnnull;
    }
}
 
//domain对象
classStudent{
    privateInteger id;
    privateString name;
    publicInteger getId() {
        returnid;
    }
    publicvoid setId(Integer id) {
        this.id = id;
    }
    publicString getName() {
        returnname;
    }
    publicvoid setName(String name) {
        this.name = name;
    }
}

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模拟Hibernate一级缓存

[1].[代码] Java代码模拟Hibernate一级缓存 跳至 [1]

[1].[代码] Java代码模拟Hibernate一级缓存跳至 [1]