OQL可以用来查询jvm堆中对象信息 将jvm堆dump下了的命令可见：https://www.yuque.com/zhqy/java/xlv2yg#469b7b22 单位：byte（B）

示例代码

package com.zhqy.oql;
import org.apache.commons.lang.StringUtils;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
/**
 * <h3>测试OQL语法</h3>
 *
 * @author zhqy
 * @version 1.0.0
 * @CreateDate 2019/7/23
 */
public class OqlMain {
    private List<String> nameList = new ArrayList<>();
    private List<Person> personList = new LinkedList<>();
    private String[] titles = new String[]{"吃货", "胖砸", "美女", "帅哥"};
    public void init(){
        nameList.add("张三");
        personList.add(new Person(nameList.get(0), 40, StringUtils.join(new String[]{titles[0], titles[1]}, ",")));
        nameList.add("李四");
        personList.add(new Person(nameList.get(1), 20, StringUtils.join(new String[]{titles[0], titles[3]}, ",")));
        nameList.add("美女");
        personList.add(new Person(nameList.get(0), 23, StringUtils.join(new String[]{titles[2]}, ",")));
    }
}
class Person{
    private String name;
    private int age;
    private String titles;
    public Person(String name, int age, String titles) {
        this.name = name;
        this.age = age;
        this.titles = titles;
    }
    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 getTitles() {
        return titles;
    }
    public void setTitles(String titles) {
        this.titles = titles;
    }
}

查看对象

select * from com.zhqy.oql.OqlMain

查看对象中某一个属性

此时直接在需要查看的属性上右击，选择“copy”->“OQL Query”即可

SELECT * FROM OBJECTS 197769

查看list的元素数量

SELECT s.size FROM OBJECTS 197769 s

根据类名查询

正则

SELECT * FROM ".*pool.*"

where条件

SELECT * FROM java.lang.Thread s where toString(s) LIKE ".*elastic.*"