一個超級特務拯救世界打擊罪犯的日誌

2017/12/16

Java 自訂例外處理

class MemberIDException extends Exception{
    public MemberIDException(String mID){
        super("ERROR: " + mID)
    }
    public void contactWith(){ // 自訂例外中的自訂方法
        System.out.println("Please try again.");
    }
}

public static void main(String[] args){
    try{
        checkMemberID("123456");
    }
    catch(MemberIDException e){
        tem.out.println(e.getMessage());
        e.contactWith(); // 自訂例外類別中的自訂方法
    }
}

public static void checkMemberID(String mID) throws MemberIDException{
    if(mID.length() != 5){
        throw new MemberIDException(mID); // 自訂例外
    }
}

轉載自http://jhengjyun.blogspot.tw/2010/06/java-extends.html

2017/12/7

2017/12/4

Servlet輸出不亂碼

程式如下

package newpackage;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class NewServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        String userInput = new String(request.getParameter("userInput").getBytes("UTF-8"));
        out.print(userInput);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        out.print("哈囉");
    }

}

不管是POST還是GET第一行都要先放response.setContentType("text/html;charset=UTF-8");這行
如果是GET，要先把在網址列取得的參數用getBytes取得並轉成UTF-8，之後才輸出。可以上方的程式碼。

最近又發生亂碼的情況了，看來還有別的會亂碼的情況我沒注意到
就是我從jsp送post請求給servlet，servlet再把這個從jsp送來的參數顯示到另一個jsp
我在servlet用System.out.println()查看這個參數，才發現進到servlet時就亂碼了，所以應該不是jsp的問題

後來我在servlet的doPost的第二行加入request.setCharacterEncoding("UTF-8");
就解決了

原本以為

2017/11/29

解決Ubuntu不能更新oh-my-zsh的問題

有時Ubuntu Server上他會問你是否更新Oh My Zsh，如下：

[Oh My Zsh] Would you like to check for updates? [Y/n]: y

Updating Oh My Zsh

error: Cannot pull with rebase: You have unstaged changes.

There was an error updating. Try again later?

按y發現他不給更新

解法在這網址：https://github.com/robbyrussell/oh-my-zsh/issues/1984#issuecomment-168351730

記得設定git的信箱和名稱

2017/11/28

在mac格式化隨身碟要選ExFAT

在mac格式化隨身碟要選ExFAT
這樣隨身碟才能同時給Windows和Mac讀寫

就這樣....

2017/10/1

mac MQTT(mosquitto)安裝

請先安裝Homebrew，要用Homebrew安裝mosquitto

安裝mosquitto

$ brew intall mosquitto

我安裝過程有出現一些Error訊息，所以安裝完後又把mosquitto刪掉，相依的套件也跟著刪掉再重新安裝一次。

Homebrew會裝在/usr/local/Cellar/mosquitto這個位置

把mosquitto加入.zshrc環境變數，這樣才可以在全域下指令操作它

打開.zshrc

$ vi .zshrc

在上面加入這行

export PATH=/usr/local/Cellar/mosquitto/1.4.14_1/sbin:$PATH

馬上讓.zshrc生效

$ source .zshrc

用brew啟動mosquitto服務

$ brew services start mosquitto

用brew停止mosquitto服務

$ brew services stop mosquitto

用brew重啟mosquitto服務

$ brew services restart mosquitto

用NodeMCU adc讀取ACS712訊號並轉換電壓電流

使用的是NodeMCU v3

ACS712(30A)

使用NodeMCU上的adc來讀取ACS712的類比訊號，直接使用NodeMCU上的VU腳位來供給ACS712 5V的電，輸出的訊號電壓準位為5V，使用2.4k歐姆與4.7k歐姆來降為3.3V，然後接回adc腳位
來源

wifi.setmode(wifi.STATION)
wifi.sta.config(ssid, passwd)
wifi.sta.connect()
wifi.sleeptype(wifi.NONE_SLEEP)

local refreshInterval = .2

local mVperAmp = 100 --100mV on 1A
local Voltage = 0
local VRMS = 0
local AmpsRMS = 0
local maxErr = 0
local avgErr = 0
local totalMeasurement = 0
local TotalPwr = 0

tmr.alarm(0, refreshInterval*1000, tmr.ALARM_SEMI, function()
    totalMeasurement = totalMeasurement + 1
    Voltage = getVPP()
    VRMS = (Voltage/2.0) * 0.707 
    AmpsRMS = (VRMS * 1000) / mVperAmp
    Pwr = AmpsRMS * 220 /10
    TotalPwr = TotalPwr + Pwr
    print(totalMeasurement..". AvrPwr: "..string.format("%.2f",TotalPwr * 10/totalMeasurement).."W - "..string.format("%.2f",AmpsRMS).."A - "..string.format("%.2f",Pwr * 10).."W")  
    print(" ")
    tmr.start(0)
end)


function getVPP()
    local result = 0
    local readValue = 0
    local maxValue = 0
    local minValue = 1024
    local nbrReadings = 0
    while (nbrReadings<1000 do="" if="" readvalue=""> maxValue) then
            maxValue = readValue
        elseif (readValue < minValue) then
            minValue = readValue
        end
        nbrReadings = nbrReadings + 1
    end
    print(totalMeasurement..". Max: "..maxValue.." - Min: "..minValue)
    result = (math.abs(maxValue - minValue - 6) * 5)/1024
    if (maxValue - minValue > maxErr) then
        maxErr = maxValue - minValue
    end
    avgErr = avgErr + (maxValue - minValue) / 10 
   
    print(totalMeasurement..". Err: "..maxValue - minValue.." maxErr: "..maxErr.. " AvgErr: "..string.format("%.2f", avgErr * 10/totalMeasurement))
    return result
end

這是加了判斷電器是否開啟，並根據條件發送通知的小改版本以吹風機為例，一打開就發送通知。

local refreshInterval = 2

local mVperAmp = 66 --66mV on 1A
local Voltage = 0
local VRMS = 0
local AmpsRMS = 0
local maxErr = 0
local avgErr = 0
local totalMeasurement = 0
local TotalPwr = 0 
airConditionerStatus = false
sendStatus = false
tmr.alarm(0, refreshInterval*1000, tmr.ALARM_AUTO, function()
   
    totalMeasurement = totalMeasurement + 1
    Voltage = getVPP()
    VRMS = (Voltage/2.0) * 0.707
    AmpsRMS = (VRMS * 1000) / mVperAmp
    
    if AmpsRMS>3 then
        airConditionerStatus = true
        while airConditionerStatus do
            if airConditionerStatus and sendStatus~=true then
                sendHttpRequest()
                sendStatus = true
                print(airConditionerStatus)
            else break
            end
        end
    else 
        airConditionerStatus = false
        sendStatus = false
    end
    
    Pwr = AmpsRMS * 220 /10
    TotalPwr = TotalPwr + Pwr
    print(totalMeasurement..". AvrPwr: "..string.format("%.2f",TotalPwr * 10/totalMeasurement).."W - "..string.format("%.2f",AmpsRMS).."A - "..string.format("%.2f",Pwr * 10).."W")
    print(" ")
end)


function sendHttpRequest()
    http.post("http://192.168.11.5:8101/ESP8266/Service",
  "Content-Type: application/json\r\n",
  "{\"Power\":\"on\"}",
  function(code, data)
    if (code < 0) then
      print("HTTP request failed")
    else
      print(code, data)
    end
  end)
--http://httpbin.org/ip
end

function getVPP()
    local result = 0
    local readValue = 0
    local maxValue = 0
    local minValue = 1024
    local nbrReadings = 0
    while (nbrReadings<1000) do
        readValue = adc.read(0)
        if (readValue > maxValue) then
            maxValue = readValue
        elseif (readValue < minValue) then
            minValue = readValue
        end
        nbrReadings = nbrReadings + 1
    end
    print(totalMeasurement..". Max: "..maxValue.." - Min: "..minValue)
    result = (math.abs(maxValue - minValue - 6) * 5)/1024
    if (maxValue - minValue > maxErr) then
        maxErr = maxValue - minValue
    end
    avgErr = avgErr + (maxValue - minValue) / 10

    print(totalMeasurement..". Err: "..maxValue - minValue.." maxErr: "..maxErr.. " AvgErr: "..string.format("%.2f", avgErr * 10/totalMeasurement))
    return result
end
--http://bit.ly/2x4yyFR

2017/9/16

在mac上安裝lua

直接搜尋lua去官網下載最新的安裝檔lua-5.3.4.tar.gz

把lua-5.3.4.tar.gz放到家目錄，並解壓縮

$ cd lua-5.3.4

這裡我不知在做啥，測試？

$ make macosx test

這才是安裝，沒打sudo他會有/usr/local/man/man1: Permission denied的訊息，所以要加 sudo

$ sudo make macosx install

測試是否安裝成功

$ lua

2017/9/13

在MacOS上燒錄ESP8266 NodeMCU韌體

之前都是在Windows上燒，沒想到在Mac上燒沒那麼容易...

因為Windows有NodeMCU Flasher這套軟體，Mac上似乎沒有...因此增加燒錄的困難

2017/12/16

2017/12/7

2017/12/4

2017/11/29

2017/11/28

2017/10/1

2017/9/16

2017/9/13

2017/8/27

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2017/8/11

2017/7/25

2017/7/18

2017/7/11

2017/7/6

2017/7/5

2017/6/23

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2017/6/18

2017/6/14

2017/6/9

2017/6/6

2017/5/9

2017/5/8

2017/4/16

2017/4/15

2017/4/9

2017/4/2

2017/3/29

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2017/3/18

2017/3/17

2017/3/13

2017/3/9

2017/3/7

2017/3/4

2017/3/3

2017/2/25

2017/2/22