java學習筆記二 2019.6.20 週四 三亞 real熱

一、
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;

public class HomeWork {
//練習題
public static void main(String[] args) {
// TODO Auto-generated method stub
String s=downloadString("https://www.qq.com", "UTF-8");
System.out.println(s);

}

// 封裝一個韓說String downLoading(URL url)
// 用來從網上下載文本內容，返回值是文本字符串

public static String downloadString(String urls, String charsetName) {
    URL url = null;
    InputStream outStream = null;
    Reader reader = null;
    String s = "";
    try {
        url = new URL(urls);
        outStream = url.openStream();
        reader = new InputStreamReader(outStream, charsetName);
        int i;
        while ((i = reader.read()) >= 0) {
            char ch = (char) i;
            // System.out.print(ch);
            s = s + ch;

        }

    } catch (IOException e) {
        // TODO Auto-generated catch block
        // e.printStackTrace();
        System.out.println("網頁打開失敗" + e.getMessage());
    } finally {

    }
    return s;

}
// 同時寫一個重載一個函數，允許指定編碼格式的重載
public static String downloadString(String urls) {
    return downloadString(urls, "UTF-8");
}

}

二、

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;

public class HomeWork2 {
//別人寫的練習題
public static void main(String[] args) {

    String s=downloadString("https://www.baidu.com");
    //String s = readTxtFile("/Users/hanzhao/Desktop/xiaoshuo.txt");
    System.out.println(s);

}

public static String downloadString(String urls, String charsetName) {
    InputStream inStream = null;
    Reader reader = null;
    String s = "";
    try {
        URL url = new URL(urls);
        inStream = url.openStream();
        reader = new InputStreamReader(inStream, charsetName);

        int i;
        while ((i = reader.read()) >= 0) {
            char ch = (char) i;
            s += ch;
        }
        return s;

    } catch (MalformedURLException e) {
        System.out.println("網址格式不正確：" + e.getMessage());
    } catch (IOException e) {
        System.out.println("讀寫失敗" + e.getMessage());
    } finally {
        IOUtils.closeQuietly(reader);
        IOUtils.closeQuietly(inStream);
    }
    return "異常";

}

public static String downloadString(String urls) {
    return downloadString(urls, "UTF-8");
}

public static String readTxtFile(String file, String charsetName) {
    InputStream inStream = null;
    Reader reader = null;
    String s = "";
    try {
        inStream = new FileInputStream(file);
        reader = new InputStreamReader(inStream, charsetName);
        int i;
        while ((i = reader.read()) >= 0) {
            char ch = (char) i;
            s += ch;
        }
        return s;

    } catch (FileNotFoundException e) {
        System.out.println("文件沒找到");
    } catch (IOException e) {
        System.out.println("讀寫錯誤");
    } finally {
        IOUtils.closeQuietly(reader);
        IOUtils.closeQuietly(inStream);
    }
    return "異常";

}

public static String readTxtFile(String file) {
    return readTxtFile(file, "UTF-8");
}

}

三、commons-I-O類庫下載
http://commons.apache.org
仿寫minicommons類庫

四、多看計算機英語文檔並翻譯，提高自學能力