Java代码 on 杨刚的个人网站

获取请求的ip地址

Fri, 13 Dec 2024 00:00:00 +0000

如果使用了nginx代理后台，则需要在nginx代理中将用户ip添加在请求头中

ResultVo

Wed, 11 Dec 2024 00:00:00 +0000

@Data
public class ResultVO<T> implements Serializable {

    private Integer code;
    private String msg;
    private T data;

    public ResultVO(int code,String msg,T data){
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    /**
     * 成功200、有数据
     * @param msg
     * @param data
     * @return
     */
    public static<T> ResultVO<T> success(String msg,T data){
        return new ResultVO<>(ResultCode.SUCCESS,msg,data);
    }

    /**
     * 成功200、无数据
     * @param msg
     * @return
     */
    public static<T> ResultVO<T> success(String msg){
        return success(msg,null);
    }

    /**
     * 失败500
     * @param msg
     * @param <T>
     * @return
     */
    public static<T> ResultVO<T> failed(String msg){
        return new ResultVO<>(ResultCode.FAILED,msg,null);
    }

    /**
     * 自定义返回
     * @param msg
     * @param code
     * @param data
     * @param <T>
     * @return
     */
    public static<T> ResultVO<T> result(String msg,Integer code,T data){
        return new ResultVO<T>(code,msg,data);
    }
}

public interface ResultCode {
    /**
     * 请求成功
     */
    int SUCCESS = 200;
    /**
     * 服务器异常
     */
    int FAILED = 500;
    /**
     * 未授权、未认证访问
     */
    int UNAUTHORIZED = 401;
    /**
     * 无权限
     */
    int NOACCESS = 403;
}

100以内的所有质数

Sat, 11 Nov 2023 00:00:00 +0000

方法一
#

public class ArraysTest {
    public static void main(String[] args) {
        int num = 0;
        // 遍历2~100的所有整数
        for (int i = 2; i <= 100; i++) {
            // 内层循环，遍历2到i
            for (int j = 2; j <= i; j++) {
                // 如果可以被除了i本身以外的数整除，跳出内层循环
                if (i % j == 0 && i != j) {
                    break;
                    // 如果不可以整除，重新开始内层循环
                } else if (i % j != 0) {
                    continue;
                    // 输出质数，并且叠加计数num
                } else {
                    System.out.print(i + ",");
                    num++;
                }
            }
        }
        System.out.println("一共" + num + "个");
    }
}

方法二
#

public class ArraysTest {
    public static void main(String[] args) {
        int sum = 0;
        for (int i = 2; i <= 100; i++) {
            boolean isFlag = true;
            for (int j = 2; j < i; j++) {
                if (i % j == 0) {
                    isFlag = false;
                }
            }
            if (isFlag == true) {
                System.out.print(i + ",");
                sum++;
            }
        }
        System.out.println("一共" + sum + "个");
    }
}

99乘法表

Sat, 11 Nov 2023 00:00:00 +0000

class ForTest{
    public static void main(String[] args){
        int a,b = 1;
        while (b < 10){
            for (a = 1;a <= b;a++){
                System.out.print(a + "x" + b + "=" + (a * b) + " ");
            }
            System.out.print("\n");
            b++;
        }
    }
}

IO复制文件

Sat, 11 Nov 2023 00:00:00 +0000

//使用IO流实现文件复制
public static void copy(String by,String to) throws IOException {
    File fileby = new File(by);
    File fileto = new File(to);
    BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(fileby));
    BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream(fileto));
    byte[] bytes = new byte[1024];
    int i;
    while ((i = bufferedInputStream.read(bytes)) != -1){
        bufferedOutputStream.write(bytes,0,i);
    }
    bufferedInputStream.close();
    bufferedOutputStream.flush();
    bufferedOutputStream.close();
}

/**
  * 复制文件夹(使用缓冲字节流)
  * @param sourcePath 源文件夹路径
  * @param targetPath 目标文件夹路径
  */
public static void copyFolder(String sourcePath,String targetPath) throws Exception{
    //源文件夹路径
    File sourceFile = new File(sourcePath);
    //目标文件夹路径
    File targetFile = new File(targetPath);

    if(!sourceFile.exists()){
        throw new Exception("文件夹不存在");
    }
    if(!sourceFile.isDirectory()){
        throw new Exception("源文件夹不是目录");
    }
    if(!targetFile.exists()){
        targetFile.mkdirs();
    }
    if(!targetFile.isDirectory()){
        throw new Exception("目标文件夹不是目录");
    }

    File[] files = sourceFile.listFiles();
    if(files == null || files.length == 0){
        return;
    }

    for(File file : files){
        //文件要移动的路径
        String movePath = targetFile+File.separator+file.getName();
        if(file.isDirectory()){
            //如果是目录则递归调用
            copyFolder(file.getAbsolutePath(),movePath);
        }else {
            //如果是文件则复制文件
            BufferedInputStream in = new BufferedInputStream(new FileInputStream(file));
            BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(movePath));

            byte[] b = new byte[1024];
            int temp = 0;
            while((temp = in.read(b)) != -1){
                out.write(b,0,temp);
            }
            out.close();
            in.close();
        }
    }
}

jsp实现分页功能

Sat, 11 Nov 2023 00:00:00 +0000

JSP:
#

<tr>
    <td colspan="9">共${pageInfo.pages}页，当前第${pageInfo.pageNum}页
        <div style="float: right">
            <button 
                    ${pageInfo.pageNum == 1 ? "disabled = 'disabled'":""}
                    onclick="pageGo(${pageInfo.pageNum - 1})">
                上一页
            </button>
            <c:forEach
                       begin="${pageInfo.pageNum < 3? 1 : pageInfo.pageNum - 2}"
                       end="${pageInfo.pageNum < 3? 1 + 4 : pageInfo.pageNum - 2 + 4}"
                       var="num">
                <c:choose>
                    <%--   当按钮超过总页数，不可点击  --%>
                    <c:when test="${num > pageInfo.pages}">
                        <button disabled="disabled">${num}</button>
                    </c:when>
                    <%--   当按钮等于当前页数，不可点击，更改样式  --%>
                    <c:when test="${num == pageInfo.pageNum}">
                        <button onclick="pageGo(${num})" disabled="disabled">${num}</button>
                    </c:when>
                    <%--   其他情况正常点击  --%>
                    <c:otherwise>
                        <button onclick="pageGo(${num})">${num}</button>
                    </c:otherwise>
                </c:choose>
            </c:forEach>
            <button 
                    ${pageInfo.pageNum == pageInfo.pages ? "disabled = 'disabled'":""}
                    onclick="pageGo(${pageInfo.pageNum + 1})">
                下一页
            </button>
        </div>
    </td>
</tr>

js:
#

function pageGo(pageGo){
    location.href="findAll.do?pageGo="+pageGo;
}

java：
#

如果是SpringMVC，需要在spring配置文件中添加插件

MySQL生成随机姓名

Sat, 11 Nov 2023 00:00:00 +0000

SELECT
CONCAT(SUBSTRING('赵钱孙李周吴郑王冯陈诸卫蒋沈韩杨朱秦尤许何吕施张孔曹严华金魏陶姜戚谢邹喻柏水窦章云苏潘葛奚范彭郎鲁韦昌马苗凤花方俞任袁柳酆鲍史唐费廉岑薛雷贺倪汤滕殷罗毕郝邬安常乐于时傅皮齐康伍余元卜顾孟平黄和穆萧尹姚邵堪汪祁毛禹狄米贝明臧计伏成戴谈宋茅庞熊纪舒屈项祝董粱杜阮蓝闵席季麻强贾路娄危江童颜郭梅盛林刁钟徐邱骆高夏蔡田樊胡凌霍虞万支柯咎管卢莫经房裘干解应宗丁宣贲邓郁单杭洪包诸左石崔吉钮龚',FLOOR(1+190*RAND()),1),SUBSTRING('明国华建文平志伟东海强晓生光林小民永杰军金健一忠洪江福祥中正振勇耀春大宁亮宇兴宝少剑云学仁涛瑞飞鹏安亚泽世汉达卫利胜敏群波成荣新峰刚家龙德庆斌辉良玉俊立浩天宏子松克清长嘉红山贤阳乐锋智青跃元武广思雄锦威启昌铭维义宗英凯鸿森超坚旭政传康继翔栋仲权奇礼楠炜友年震鑫雷兵万星骏伦绍麟雨行才希彦兆贵源有景升惠臣慧开章润高佳虎根远力进泉茂毅富博霖顺信凡豪树和恩向道川彬柏磊敬书鸣芳培全炳基冠晖京欣廷哲保秋君劲轩帆若连勋祖锡吉崇钧田石奕发洲彪钢运伯满庭申湘皓承梓雪孟其潮冰怀鲁裕翰征谦航士尧标洁城寿枫革纯风化逸腾岳银鹤琳显焕来心凤睿勤延凌昊西羽百捷定琦圣佩麒虹如靖日咏会久昕黎桂玮燕可越彤雁孝宪萌颖艺夏桐月瑜沛诚夫声冬奎扬双坤镇楚水铁喜之迪泰方同滨邦先聪朝善非恒晋汝丹为晨乃秀岩辰洋然厚灿卓杨钰兰怡灵淇美琪亦晶舒菁真涵爽雅爱依静棋宜男蔚芝菲露娜珊雯淑曼萍珠诗璇琴素梅玲蕾艳紫珍丽仪梦倩伊茜妍碧芬儿岚婷菊妮媛莲娟一',FLOOR(1+400*RAND()),1),SUBSTRING('明国华建文平志伟东海强晓生光林小民永杰军金健一忠洪江福祥中正振勇耀春大宁亮宇兴宝少剑云学仁涛瑞飞鹏安亚泽世汉达卫利胜敏群波成荣新峰刚家龙德庆斌辉良玉俊立浩天宏子松克清长嘉红山贤阳乐锋智青跃元武广思雄锦威启昌铭维义宗英凯鸿森超坚旭政传康继翔栋仲权奇礼楠炜友年震鑫雷兵万星骏伦绍麟雨行才希彦兆贵源有景升惠臣慧开章润高佳虎根远力进泉茂毅富博霖顺信凡豪树和恩向道川彬柏磊敬书鸣芳培全炳基冠晖京欣廷哲保秋君劲轩帆若连勋祖锡吉崇钧田石奕发洲彪钢运伯满庭申湘皓承梓雪孟其潮冰怀鲁裕翰征谦航士尧标洁城寿枫革纯风化逸腾岳银鹤琳显焕来心凤睿勤延凌昊西羽百捷定琦圣佩麒虹如靖日咏会久昕黎桂玮燕可越彤雁孝宪萌颖艺夏桐月瑜沛诚夫声冬奎扬双坤镇楚水铁喜之迪泰方同滨邦先聪朝善非恒晋汝丹为晨乃秀岩辰洋然厚灿卓杨钰兰怡灵淇美琪亦晶舒菁真涵爽雅爱依静棋宜男蔚芝菲露娜珊雯淑曼萍珠诗璇琴素梅玲蕾艳紫珍丽仪梦倩伊茜妍碧芬儿岚婷菊妮媛莲娟一',FLOOR(1+400*RAND()),1))

查杀端口

Sat, 11 Nov 2023 00:00:00 +0000

windows下cmd进行操作
#

#查询端口的pid
netstat -ano | findstr "port"
#关闭端口
taskkill /f /t /pid p

递归解决斐波那契数列

Sat, 11 Nov 2023 00:00:00 +0000

/**
* 使用递归计算斐波那契数列
* 1 1 2 3 5 8 13 21 34 55 
*/
public class Fibonacci {  
    public int fibonacciArr(int n){    
        if (n == 1){          
            return 1;      
        }else if (n == 2){  
            return 1;     
        }else {       
            return fibonacciArr(n - 1) + fibonacciArr(n - 2);     
        }   
    }
}

递归删除文件夹内所有文件

Sat, 11 Nov 2023 00:00:00 +0000

//编写Java程序：删除指定的文件或文件夹，如果文件夹中有文件或子文件夹也一并删除
public static void deleteAll(File file){
    if (file.isDirectory()){
        File[] files = file.listFiles();
        if (files != null){
            for (File fi : files){
                deleteAll(fi);
            }
        }
    }
    file.delete();
}

动态生成验证码

Sat, 11 Nov 2023 00:00:00 +0000

public class ImageServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //设置当前页面的文档类型，默认text/html
        resp.setContentType("image/gif");
        //申请了一块画布
        BufferedImage bufferedImage = new BufferedImage(50,20,BufferedImage.TYPE_INT_RGB);
        //得到一个画笔,设置背景颜色为白色
        Graphics graphics = bufferedImage.getGraphics();
        graphics.setColor(Color.white);
        graphics.fillRect(0, 0, 50, 20);
        graphics.setColor(Color.red);
        //生成验证码，随机颜色以及数字字母
        String number = "";
        for (int i = 0; i < 4; i++) {
            graphics.setColor(getRandomColor());
            String code = getRandomChar();
            number+=code;
            graphics.drawString(code, 10 + (i * 10), 12);
        }
        //生成五条随机的干扰线
        for (int i = 0; i < 5; i++) {
            graphics.setColor(getRandomColor());
            graphics.drawLine(new Random().nextInt(50), new Random().nextInt(20), new Random().nextInt(50), new Random().nextInt(20));
        }
        //响应给浏览器
        ImageIO.write(bufferedImage, "jpg", resp.getOutputStream());
    }
    //生成随机颜色
    public Color getRandomColor(){
        return new Color(new Random().nextInt(255), new Random().nextInt(255), new Random().nextInt(255));
    }
    //所有的数字字母，存入list集合
    public String getRandomChar(){
        ArrayList list = new ArrayList();
        for (int i = 0; i < 10; i++) {
            list.add(i);
        }
        for (int i = 65; i < 65+26; i++) {
            list.add((char)i);
        }
        for (int i = 97; i < 97+26; i++) {
            list.add((char)i);
        }
        return list.get(new Random().nextInt(list.size()))+"";
    }
}

获取异常堆栈信息

Sat, 11 Nov 2023 00:00:00 +0000

private String getStackTraceInfo(Exception e){
    StackTraceElement[] stackTraceElements = e.getStackTrace();
    String result = e.toString() + "\n";
    for (int index = stackTraceElements.length - 1; index >= 0; --index) {
        result += "at [" + stackTraceElements[index].getClassName() + ",";
        result += stackTraceElements[index].getFileName() + ",";
        result += stackTraceElements[index].getMethodName() + ",";
        result += stackTraceElements[index].getLineNumber() + "]\n";
    }
    return result;
}

六个不重复随机数数组

Sat, 11 Nov 2023 00:00:00 +0000

public class ArrayTest {
    public static void main(String[] args) {
        int[] arr = new int[6];
        int i = 0;
        label: while (i < 6) {
            int num = (int) (Math.random() * 30 + 1);
            arr[i] = num;
            for (int j = 0; j < i; j++) {
                if (arr[j] == arr[i]) {
                    continue label;
                }
            }
            i++;
        }
        for (int j = 0; j < 6; j++) {
            System.out.print(arr[j] + "\t");
        }
    }
}

十进制整数转化为二进制

Sat, 11 Nov 2023 00:00:00 +0000

public static String tran(int a){
    //con:商；rem:余数;last:最后承载结果的变量
    int con;
    String rem = "",last = "";
    //循环将余数储存在变量rem中
    flag:while (true){
        rem += (a % 2 + "");
        a /= 2;
        if (a == 0){
            break flag;
        }
    }
    //将获得的余数倒置，存储在变量last中
    for (int i = rem.length() - 1;i >= 0;i--){
        last += rem.charAt(i);
    }
    return last;
}

序列化及反序列化

Sat, 11 Nov 2023 00:00:00 +0000

//序列化
public static void serialization(List list,String file) throws IOException {
    File file1 = new File(file);
    ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream(file));
    for (Object o : list){
        outputStream.writeObject(o);
    }
    outputStream.flush();
    outputStream.close();
}
//反序列化
public static List deserialization(String file) throws IOException, ClassNotFoundException {
    File file1 = new File(file);
    List list = new ArrayList();
    ObjectInputStream inputStream = new ObjectInputStream(new FileInputStream(file));
    Object o;
    while (true){
        try {
            o = inputStream.readObject();
        }catch (Exception e){
            break;
        }
        list.add(o);
    }
    inputStream.close();
    return list;
}

杨辉三角

Sat, 11 Nov 2023 00:00:00 +0000

public class ArrayTest1 {
    public static void main(String[] args) {
        // 创建二维数组并初始化，并且内层数组长度不确定
        int[][] yangHui = new int[10][];
        // 赋值
        // 遍历外层数组
        for (int i = 0; i < yangHui.length; i++) {
            // 初始化内层数组
            yangHui[i] = new int[i + 1];
            // 遍历内层数组
            for (int j = 0; j < yangHui[i].length; j++) {
                // 如果是首位或末位元素，赋值为1
                if (j == 0 || j == (yangHui[i].length - 1)) {
                    yangHui[i][j] = 1;
                    // 其他中间的元素，按照公式赋值
                } else {
                    yangHui[i][j] = yangHui[i - 1][j - 1] + yangHui[i - 1][j];
                }
            }
        }
        // 输出
        // 遍历外层数组
        for (int i = 0; i < yangHui.length; i++) {
            // 输出最左侧的行号
            System.out.print("[" + i + "]\t");
            // 遍历内层数组
            for (int j = 0; j < yangHui[i].length; j++) {
                // 输出元素
                System.out.print(yangHui[i][j] + "\t");
            }
            // 输出完一行后换行
            System.out.println();
            // 输出最后一行的列数
            // 判断是否输出到最后一行
            if (i == yangHui.length - 1) {
                for (int j = 0; j < yangHui[yangHui.length - 1].length; j++) {
                    System.out.print("\t" + "[" + j + "]");
                }
            }
        }
    }
}

中文字符串转拼音

Sat, 11 Nov 2023 00:00:00 +0000

<dependency>
    <groupId>com.belerweb</groupId>
    <artifactId>pinyin4j</artifactId>
    <version>2.5.0</version>
</dependency>

@Slf4j
public class PinYinUtil {
    /**
     * 将字符串中的中文转化为拼音,其他字符不变
     *
     * @param inputString
     * @return
     */
    public static String getPinYin(String inputString) {
        HanyuPinyinOutputFormat format = new HanyuPinyinOutputFormat();
        format.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        format.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        format.setVCharType(HanyuPinyinVCharType.WITH_V);

        char[] input = inputString.trim().toCharArray();
        String output = "";

        try {
            for (int i = 0; i < input.length; i++) {
                if (java.lang.Character.toString(input[i]).matches("[\\u4E00-\\u9FA5]+")) {
                    String[] temp = PinyinHelper.toHanyuPinyinStringArray(input[i], format);
                    output += temp[0];
                } else
                    output += java.lang.Character.toString(input[i]);
            }
        } catch (BadHanyuPinyinOutputFormatCombination e) {
            log.error("中文转拼音出错",e);
        }
        return output;
    }
    /**
     * 获取所有汉字串拼音首字母，英文字符不变
     * @param chinese 汉字串
     * @return 汉语拼音首字母
     */
    public static String getFirstSpell(String chinese) {
        StringBuffer pybf = new StringBuffer();
        char[] arr = chinese.toCharArray();
        HanyuPinyinOutputFormat defaultFormat = new HanyuPinyinOutputFormat();
        defaultFormat.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        defaultFormat.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] > 128) {
                try {
                    String[] temp = PinyinHelper.toHanyuPinyinStringArray(arr[i], defaultFormat);
                    if (temp != null) {
                        pybf.append(temp[0].charAt(0));
                    }
                } catch (BadHanyuPinyinOutputFormatCombination e) {
                    e.printStackTrace();
                }
            } else {
                pybf.append(arr[i]);
            }
        }
        return pybf.toString().replaceAll("\\W", "").trim();
    }

}

Java代码 on 杨刚的个人网站

获取请求的ip地址

ResultVo

100以内的所有质数

方法一 #

方法二 #

99乘法表

IO复制文件

jsp实现分页功能

JSP: #

js: #

java： #

MySQL生成随机姓名

查杀端口

windows下cmd进行操作 #

递归解决斐波那契数列

递归删除文件夹内所有文件

动态生成验证码

获取异常堆栈信息

六个不重复随机数数组

十进制整数转化为二进制

序列化及反序列化

杨辉三角

中文字符串转拼音

方法一
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方法二
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JSP:
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js:
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java：
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windows下cmd进行操作
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