{"id":228272,"date":"2024-05-11T21:05:39","date_gmt":"2024-05-11T13:05:39","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/228272.html"},"modified":"2024-05-11T21:05:45","modified_gmt":"2024-05-11T13:05:45","slug":"%e6%9c%89%e5%93%aa%e4%ba%9b%e5%be%88%e7%bb%8f%e5%85%b8%e7%9a%84java%e4%bb%a3%e7%a0%81%e7%89%87%e6%ae%b5","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/228272.html","title":{"rendered":"\u6709\u54ea\u4e9b\u5f88\u7ecf\u5178\u7684java\u4ee3\u7801\u7247\u6bb5"},"content":{"rendered":"

\"\u6709\u54ea\u4e9b\u5f88\u7ecf\u5178\u7684java\u4ee3\u7801\u7247\u6bb5\"<\/p>\n

\u8981\u8c08\u8bba\u4e00\u4e9b\u975e\u5e38\u7ecf\u5178\u7684Java\u4ee3\u7801\u7247\u6bb5\uff0c\u6211\u4eec\u5fc5\u987b\u5148\u63d0\u4e00\u4e9b\u5e7f\u4e3a\u4eba\u77e5\u7684\u5b9e\u73b0\u548c\u6a21\u5f0f\uff0c\u8fd9\u4e9b\u5b9e\u73b0\u6982\u5ff5\u4e0a\u7b80\u5355\u4e14\u5728\u5b9e\u9645\u5de5\u4f5c\u4e2d\u5e7f\u6cdb\u4f7f\u7528\u3002\u7ecf\u5178\u7684\u4ee3\u7801\u7247\u6bb5\u4e3b\u8981\u5305\u62ec\u5355\u4f8b\u6a21\u5f0f\u3001\u96c6\u5408\u6846\u67b6\u7684\u4f7f\u7528\u3001\u5b57\u7b26\u4e32\u64cd\u4f5c\u3001\u6587\u4ef6I\/O\u64cd\u4f5c\u4ee5\u53ca\u5f02\u5e38\u5904\u7406<\/strong>\u3002\u7279\u522b\u662f\u5355\u4f8b\u6a21\u5f0f\u7684\u4ee3\u7801\u5b9e\u73b0\uff0c\u5b83\u4e0d\u4ec5\u7b80\u6d01\u800c\u4e14\u9ad8\u6548<\/strong>\uff0c\u662f\u786e\u4fdd\u5728\u6574\u4e2a\u5e94\u7528\u7a0b\u5e8f\u4e2d\u53ea\u6709\u4e00\u4e2a\u7c7b\u5b9e\u4f8b\u7684\u7ecf\u5178\u65b9\u5f0f\u3002<\/p>\n<\/p>\n

\u4e00\u3001\u5355\u4f8b\u8bbe\u8ba1\u6a21\u5f0f<\/h3>\n<\/p>\n

\u5355\u4f8b<\/strong>\u6a21\u5f0f\u662f\u4e00\u79cd\u8bbe\u8ba1\u6a21\u5f0f\uff0c\u7528\u4e8e\u786e\u4fdd\u4e00\u4e2a\u7c7b\u53ea\u6709\u4e00\u4e2a\u5b9e\u4f8b\uff0c\u5e76\u63d0\u4f9b\u4e00\u4e2a\u5168\u5c40\u8bbf\u95ee\u70b9\u3002<\/p>\n<\/p>\n

public class Singleton {<\/p>\n
    private static volatile Singleton instance = null;<\/p>\n
    private Singleton() {}<\/p>\n
    public static Singleton getInstance() {<\/p>\n
        if (instance == null) {<\/p>\n
            synchronized (Singleton.class) {<\/p>\n
                if (instance == null) {<\/p>\n
                    instance = new Singleton();<\/p>\n
                }<\/p>\n
            }<\/p>\n
        }<\/p>\n
        return instance;<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u6bb5\u4ee3\u7801\u4e2d\u4f7f\u7528\u201c\u53cc\u91cd\u68c0\u67e5\u9501\u5b9a\uff08double-checked locking\uff09\u201d\u6765\u51cf\u5c11\u540c\u6b65\u7684\u4f7f\u7528\uff0c\u56e0\u4e3a\u540c\u6b65\u4f1a\u5bfc\u81f4\u6027\u80fd\u4e0b\u964d\u3002volatile\u5173\u952e\u5b57\u786e\u4fdd\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u7684\u5b89\u5168\u6027\u3002<\/p>\n<\/p>\n
\u4e8c\u3001\u96c6\u5408\u6846\u67b6\u7684\u904d\u5386<\/h3>\n<\/p>\n
\u96c6\u5408\u6846\u67b6<\/strong>\u662f\u5904\u7406\u4e00\u7ec4\u5bf9\u8c61\u7684\u5f3a\u5927\u5de5\u5177\u3002<\/p>\n<\/p>\n
import java.util.*;<\/p>\n
public class CollectionDemo {<\/p>\n
    public static void mAI<\/a>n(String args[]) {<\/p>\n
        List<String> list = new ArrayList<>();<\/p>\n
        list.add("Java");<\/p>\n
        list.add("Python");<\/p>\n
        list.add("C++");<\/p>\n
        for(String language : list) {<\/p>\n
            System.out.println(language);<\/p>\n
        }<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f7f\u7528\u589e\u5f3a\u578bfor\u5faa\u73af\u6765\u904d\u5386\u96c6\u5408\u662f\u4e00\u79cd\u7b80\u6d01\u660e\u4e86\u7684\u505a\u6cd5\u3002<\/p>\n<\/p>\n
\u4e09\u3001\u5b57\u7b26\u4e32\u64cd\u4f5c<\/h3>\n<\/p>\n
\u5b57\u7b26\u4e32\u64cd\u4f5c<\/strong>\u5728Java\u4e2d\u975e\u5e38\u5e38\u89c1\uff0cString\u7c7b\u4e2d\u7684\u65b9\u6cd5\u88ab\u5e7f\u6cdb\u4f7f\u7528\u3002<\/p>\n<\/p>\n
public class StringOperations {<\/p>\n
    public static void main(String args[]) {<\/p>\n
        String s1 = "Hello, World";<\/p>\n
        String s2 = "JAVA";<\/p>\n
        System.out.println(s1.toLowerCase());<\/p>\n
        System.out.println(s2.toUpperCase());<\/p>\n
        System.out.println(s1.substring(0, 5));<\/p>\n
        System.out.println(s1.replace('o', 'a'));<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8fd9\u4e9b\u64cd\u4f5c\u6db5\u76d6\u4e86\u5e38\u89c1\u7684\u5b57\u7b26\u4e32\u64cd\u4f5c\u65b9\u6cd5\uff0c\u5305\u62ec\u5927\u5c0f\u5199\u8f6c\u6362\u3001\u5b57\u7b26\u4e32\u5207\u5272\u4ee5\u53ca\u5b57\u7b26\u66ff\u6362\u3002<\/p>\n<\/p>\n
\u56db\u3001\u6587\u4ef6I\/O\u64cd\u4f5c<\/h3>\n<\/p>\n
\u6587\u4ef6\u8f93\u5165\/\u8f93\u51fa\uff08I\/O\uff09\u662fJava\u4e2d\u7684\u57fa\u7840\u90e8\u5206\u3002<\/p>\n<\/p>\n
import java.io.*;<\/p>\n
public class FileOperations {<\/p>\n
    public static void main(String args[]) {<\/p>\n
        File file = new File("input.txt");<\/p>\n
        try (BufferedReader reader = new BufferedReader(new FileReader(file));<\/p>\n
             BufferedWriter writer = new BufferedWriter(new FileWriter("output.txt"))) {<\/p>\n
            String line;<\/p>\n
            while ((line = reader.readLine()) != null) {<\/p>\n
                writer.write(line);<\/p>\n
                writer.newLine();<\/p>\n
            }<\/p>\n
        } catch (IOException e) {<\/p>\n
            e.printStackTrace();<\/p>\n
        }<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f7f\u7528\u5e26\u8d44\u6e90\u7684try\u5757\u80fd\u591f\u81ea\u52a8\u5904\u7406\u8d44\u6e90\u7684\u5173\u95ed\u64cd\u4f5c\uff0c\u8fd9\u6d88\u9664\u4e86\u4ee5\u5f80\u5728finally\u5757\u4e2d\u624b\u52a8\u5173\u95ed\u6d41\u7684\u9700\u6c42\u3002<\/p>\n<\/p>\n
\u4e94\u3001\u5f02\u5e38\u5904\u7406<\/h3>\n<\/p>\n
\u6b63\u786e\u7684\u5f02\u5e38\u5904\u7406\u80fd\u591f\u4f7f\u4ee3\u7801\u66f4\u52a0\u5065\u58ee\u3002<\/p>\n<\/p>\n
public class ExceptionHandling {<\/p>\n
    public static void main(String args[]) {<\/p>\n
        try {<\/p>\n
            int result = divide(10, 0);<\/p>\n
            System.out.println(result);<\/p>\n
        } catch (ArithmeticException e) {<\/p>\n
            System.err.println("Arithmetic Error: " + e.getMessage());<\/p>\n
        }<\/p>\n
    }<\/p>\n
    private static int divide(int a, int b) {<\/p>\n
        return a \/ b;<\/p>\n
    }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u6355\u83b7\u7279\u5b9a\u7684\u5f02\u5e38\u53ef\u4ee5\u9488\u5bf9\u6027\u5730\u5904\u7406\u9519\u8bef\u60c5\u51b5\uff0c\u5e76\u901a\u8fc7e.getMessage()\u83b7\u53d6\u5177\u4f53\u9519\u8bef\u4fe1\u606f\u3002<\/p>\n<\/p>\n
\u4ee5\u4e0a\u662fJava\u4e2d\u4e00\u4e9b\u7ecf\u5178\u7684\u4ee3\u7801\u7247\u6bb5\uff0c\u5b83\u4eec\u662f\u5f88\u591aJava\u7a0b\u5e8f\u7684\u57fa\u77f3\u3002\u7406\u89e3\u548c\u638c\u63e1\u8fd9\u4e9b\u4ee3\u7801\u6a21\u5f0f\u5bf9\u4e8eJava\u521d\u5b66\u8005\u548c\u5b9e\u8df5\u8005\u90fd\u662f\u975e\u5e38\u6709\u4ef7\u503c\u7684\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
1. \u5982\u4f55\u4f7f\u7528Java\u5b9e\u73b0\u5b57\u7b26\u4e32\u53cd\u8f6c\uff1f<\/strong><\/p>\n
\u901a\u8fc7\u4f7f\u7528StringBuilder\u7c7b\u7684reverse()\u65b9\u6cd5\u53ef\u4ee5\u5f88\u65b9\u4fbf\u5730\u5b9e\u73b0\u5b57\u7b26\u4e32\u53cd\u8f6c\u3002\u4f8b\u5982\uff1a<\/p>\n
String originalString = "Hello World!";\nStringBuilder reversedString = new StringBuilder(originalString).reverse();\nSystem.out.println(reversedString.toString());\n<\/code><\/pre>\n
2. \u5982\u4f55\u5728Java\u4e2d\u5224\u65ad\u4e00\u4e2a\u5b57\u7b26\u4e32\u662f\u5426\u662f\u6570\u5b57\uff1f<\/strong><\/p>\n
\u53ef\u4ee5\u4f7f\u7528\u6b63\u5219\u8868\u8fbe\u5f0f\u6765\u5224\u65ad\u4e00\u4e2a\u5b57\u7b26\u4e32\u662f\u5426\u53ea\u5305\u542b\u6570\u5b57\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n
String input = "12345";\nif (input.matches("\\\\d+")) {\n    System.out.println("\u662f\u6570\u5b57");\n} else {\n    System.out.println("\u4e0d\u662f\u6570\u5b57");\n}\n<\/code><\/pre>\n
3. \u5982\u4f55\u5728Java\u4e2d\u751f\u6210\u968f\u673a\u6570\uff1f<\/strong><\/p>\n
\u53ef\u4ee5\u4f7f\u7528Java\u7684Random\u7c7b\u6765\u751f\u6210\u968f\u673a\u6570\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u751f\u6210\u6307\u5b9a\u8303\u56f4\u5185\u968f\u673a\u6574\u6570\u7684\u793a\u4f8b\uff1a<\/p>\n
import java.util.Random;\n\nRandom random = new Random();\nint min = 1;\nint max = 10;\nint randomNumber = random.nextInt(max - min + 1) + min;\nSystem.out.println(randomNumber);\n<\/code><\/pre>\n
\u4ee5\u4e0a\u662f\u51e0\u4e2a\u7ecf\u5178\u7684Java\u4ee3\u7801\u7247\u6bb5\uff0c\u5e0c\u671b\u80fd\u5bf9\u60a8\u6709\u6240\u5e2e\u52a9\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"\u8981\u8c08\u8bba\u4e00\u4e9b\u975e\u5e38\u7ecf\u5178\u7684Java\u4ee3\u7801\u7247\u6bb5\uff0c\u6211\u4eec\u5fc5\u987b\u5148\u63d0\u4e00\u4e9b\u5e7f\u4e3a\u4eba\u77e5\u7684\u5b9e\u73b0\u548c\u6a21\u5f0f\uff0c\u8fd9\u4e9b\u5b9e\u73b0\u6982\u5ff5\u4e0a\u7b80\u5355\u4e14\u5728\u5b9e\u9645\u5de5\u4f5c\u4e2d\u5e7f […]","protected":false},"author":3,"featured_media":228279,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/228272"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=228272"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/228272\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/228279"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=228272"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=228272"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=228272"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}