MAT中 Histogram 的功能

「爱情、让人受尽委屈。」 2022-09-09 01:55 141阅读 0赞

# 一 代码 #

package chapter03;
    
    import java.util.ArrayList;
    import java.util.Random;
    
    /**
    * -Xms600m -Xmx600m -XX:SurvivorRatio=8
    * 老年代：400m
    * 伊甸园：160m
    * s0:20m
    * s1:20m
    */
    public class OOMTest {
        public static void main(String[] args) {
            ArrayList<Picture> list = new ArrayList<>();
            while (true) {
                try {
                    Thread.sleep(5);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                list.add(new Picture(new Random().nextInt(100 * 50)));
            }
        }
    }
    
    class Picture {
        private byte[] pixels;
    
    
        public Picture(int length) {
            this.pixels = new byte[length];
        }
    }

# 二 Histogram 基本界面展示 #

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16][]

浅堆：不包括引用对象大小的计算。引用的4个字节还是要计算。

深堆：包括引用对象大小的计算。

有点类似深拷贝和浅拷贝。

# 三 分析某个类 #

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

# 四 类的分组功能 #

## 1 按包分组 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 2][]

## 2 分组后的样子 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 3][]

# 五 排序 #

## 1 按类名排序 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 4][]

## 2 排序后的样子 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_19_color_FFFFFF_t_70_g_se_x_16][]

# 六 正则匹配 #

## 1 填写正则表达式的位置 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_19_color_FFFFFF_t_70_g_se_x_16 1][]

2 例如输入 Pic ，再回车。

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_17_color_FFFFFF_t_70_g_se_x_16][]

# 七 GC Roots分析 #

## 第一步：操作菜单 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 5][]

## 第二步：展示分析结果 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 6][]

# 八 dump的直方图比较 #

## 1 操作菜单 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 7][]

## 2 选择要比较的dump ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_10_color_FFFFFF_t_70_g_se_x_16][]

## 3 比较结果 ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16 8][]

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