HttpServer
文件信息
- 📄 原文件：
HttpServer.java - 🔤 语言：java
简单 HTTP 服务器 使用 Java 内置的 HttpServer 实现简单的 REST API。 功能：
- 基本路由
- JSON 响应
- 请求日志
- 错误处理 运行后访问：
- http://localhost:8080/ 首页
- http://localhost:8080/api/time 当前时间
- http://localhost:8080/api/echo 回显请求
- http://localhost:8080/api/users 用户列表
完整代码
java
import com.sun.net.httpserver.*;
import java.io.*;
import java.net.*;
import java.nio.charset.*;
import java.util.*;
import java.util.concurrent.*;
import java.time.*;
import java.time.format.*;
/**
* ============================================================
* 简单 HTTP 服务器
* ============================================================
* 使用 Java 内置的 HttpServer 实现简单的 REST API。
*
* 功能：
* - 基本路由
* - JSON 响应
* - 请求日志
* - 错误处理
*
* 运行后访问：
* - http://localhost:8080/ 首页
* - http://localhost:8080/api/time 当前时间
* - http://localhost:8080/api/echo 回显请求
* - http://localhost:8080/api/users 用户列表
* ============================================================
*/
public class HttpServer {
private static final int PORT = 8080;
private static final DateTimeFormatter FORMATTER =
DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
// 模拟数据库
private static final List<User> users = new CopyOnWriteArrayList<>(List.of(
new User(1, "Alice", "[email protected]"),
new User(2, "Bob", "[email protected]"),
new User(3, "Charlie", "[email protected]")
));
public static void main(String[] args) throws IOException {
com.sun.net.httpserver.HttpServer server =
com.sun.net.httpserver.HttpServer.create(new InetSocketAddress(PORT), 0);
// 配置路由
server.createContext("/", HttpServer::handleHome);
server.createContext("/api/time", HttpServer::handleTime);
server.createContext("/api/echo", HttpServer::handleEcho);
server.createContext("/api/users", HttpServer::handleUsers);
// 使用虚拟线程（Java 21+）
server.setExecutor(Executors.newVirtualThreadPerTaskExecutor());
server.start();
System.out.println("服务器启动在 http://localhost:" + PORT);
System.out.println("\n可用端点:");
System.out.println(" GET / - 首页");
System.out.println(" GET /api/time - 当前时间");
System.out.println(" POST /api/echo - 回显请求体");
System.out.println(" GET /api/users - 获取用户列表");
System.out.println(" POST /api/users - 创建用户");
System.out.println("\n按 Ctrl+C 停止服务器");
}
/**
* 首页处理
*/
private static void handleHome(HttpExchange exchange) throws IOException {
logRequest(exchange);
String html = """
<!DOCTYPE html>
<html>
<head>
<title>Java HTTP Server</title>
<style>
body { font-family: Arial, sans-serif; max-width: 800px; margin: 50px auto; padding: 20px; }
h1 { color: #333; }
.endpoint { background: #f5f5f5; padding: 10px; margin: 10px 0; border-radius: 5px; }
code { background: #e0e0e0; padding: 2px 6px; border-radius: 3px; }
</style>
</head>
<body>
<h1>Java HTTP Server</h1>
<p>欢迎使用 Java 内置 HTTP 服务器！</p>
<h2>可用端点</h2>
<div class="endpoint">
<code>GET /api/time</code> - 获取当前时间
</div>
<div class="endpoint">
<code>POST /api/echo</code> - 回显请求体
</div>
<div class="endpoint">
<code>GET /api/users</code> - 获取用户列表
</div>
<div class="endpoint">
<code>POST /api/users</code> - 创建用户
</div>
<h2>示例</h2>
<pre>
curl http://localhost:8080/api/time
curl -X POST -d "Hello" http://localhost:8080/api/echo
curl http://localhost:8080/api/users
</pre>
</body>
</html>
""";
sendResponse(exchange, 200, "text/html", html);
}
/**
* 时间 API
*/
private static void handleTime(HttpExchange exchange) throws IOException {
logRequest(exchange);
if (!exchange.getRequestMethod().equals("GET")) {
sendError(exchange, 405, "Method Not Allowed");
return;
}
String json = """
{
"timestamp": "%s",
"unix": %d,
"timezone": "%s"
}
""".formatted(
LocalDateTime.now().format(FORMATTER),
System.currentTimeMillis() / 1000,
ZoneId.systemDefault().getId()
);
sendResponse(exchange, 200, "application/json", json);
}
/**
* Echo API
*/
private static void handleEcho(HttpExchange exchange) throws IOException {
logRequest(exchange);
if (!exchange.getRequestMethod().equals("POST")) {
sendError(exchange, 405, "Method Not Allowed");
return;
}
String body = new String(exchange.getRequestBody().readAllBytes(), StandardCharsets.UTF_8);
String contentType = exchange.getRequestHeaders().getFirst("Content-Type");
String json = """
{
"method": "%s",
"path": "%s",
"contentType": "%s",
"contentLength": %d,
"body": "%s",
"headers": %s
}
""".formatted(
exchange.getRequestMethod(),
exchange.getRequestURI().getPath(),
contentType != null ? contentType : "none",
body.length(),
escapeJson(body),
headersToJson(exchange.getRequestHeaders())
);
sendResponse(exchange, 200, "application/json", json);
}
/**
* 用户 API
*/
private static void handleUsers(HttpExchange exchange) throws IOException {
logRequest(exchange);
String method = exchange.getRequestMethod();
switch (method) {
case "GET" -> handleGetUsers(exchange);
case "POST" -> handleCreateUser(exchange);
default -> sendError(exchange, 405, "Method Not Allowed");
}
}
private static void handleGetUsers(HttpExchange exchange) throws IOException {
// 解析查询参数
String query = exchange.getRequestURI().getQuery();
Map<String, String> params = parseQuery(query);
List<User> result = users;
// 简单过滤
if (params.containsKey("name")) {
String name = params.get("name");
result = users.stream()
.filter(u -> u.name().toLowerCase().contains(name.toLowerCase()))
.toList();
}
StringBuilder json = new StringBuilder("[\n");
for (int i = 0; i < result.size(); i++) {
User u = result.get(i);
json.append("""
{
"id": %d,
"name": "%s",
"email": "%s"
}""".formatted(u.id(), u.name(), u.email()));
if (i < result.size() - 1) json.append(",");
json.append("\n");
}
json.append("]");
sendResponse(exchange, 200, "application/json", json.toString());
}
private static void handleCreateUser(HttpExchange exchange) throws IOException {
String body = new String(exchange.getRequestBody().readAllBytes(), StandardCharsets.UTF_8);
// 简单解析（实际应使用 JSON 库）
String name = extractJsonValue(body, "name");
String email = extractJsonValue(body, "email");
if (name == null || email == null) {
sendError(exchange, 400, "Missing name or email");
return;
}
int newId = users.stream().mapToInt(User::id).max().orElse(0) + 1;
User newUser = new User(newId, name, email);
users.add(newUser);
String json = """
{
"id": %d,
"name": "%s",
"email": "%s",
"message": "User created successfully"
}
""".formatted(newUser.id(), newUser.name(), newUser.email());
sendResponse(exchange, 201, "application/json", json);
}
// ============================================================
// 辅助方法
// ============================================================
private static void sendResponse(HttpExchange exchange, int code, String contentType, String body)
throws IOException {
byte[] bytes = body.getBytes(StandardCharsets.UTF_8);
exchange.getResponseHeaders().set("Content-Type", contentType + "; charset=utf-8");
exchange.sendResponseHeaders(code, bytes.length);
try (OutputStream os = exchange.getResponseBody()) {
os.write(bytes);
}
}
private static void sendError(HttpExchange exchange, int code, String message) throws IOException {
String json = """
{
"error": true,
"code": %d,
"message": "%s"
}
""".formatted(code, message);
sendResponse(exchange, code, "application/json", json);
}
private static void logRequest(HttpExchange exchange) {
String time = LocalDateTime.now().format(FORMATTER);
String method = exchange.getRequestMethod();
String path = exchange.getRequestURI().getPath();
String remote = exchange.getRemoteAddress().toString();
System.out.printf("[%s] %s %s from %s%n", time, method, path, remote);
}
private static Map<String, String> parseQuery(String query) {
Map<String, String> params = new HashMap<>();
if (query == null || query.isEmpty()) return params;
for (String pair : query.split("&")) {
String[] kv = pair.split("=", 2);
if (kv.length == 2) {
params.put(
URLDecoder.decode(kv[0], StandardCharsets.UTF_8),
URLDecoder.decode(kv[1], StandardCharsets.UTF_8)
);
}
}
return params;
}
private static String escapeJson(String s) {
return s.replace("\\", "\\\\")
.replace("\"", "\\\"")
.replace("\n", "\\n")
.replace("\r", "\\r")
.replace("\t", "\\t");
}
private static String headersToJson(Headers headers) {
StringBuilder sb = new StringBuilder("{");
boolean first = true;
for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
if (!first) sb.append(", ");
sb.append("\"").append(entry.getKey()).append("\": \"")
.append(String.join(", ", entry.getValue())).append("\"");
first = false;
}
sb.append("}");
return sb.toString();
}
private static String extractJsonValue(String json, String key) {
// 简单的 JSON 值提取（实际应使用 JSON 库）
String pattern = "\"" + key + "\"\\s*:\\s*\"([^\"]*)\"";
java.util.regex.Matcher matcher = java.util.regex.Pattern.compile(pattern).matcher(json);
return matcher.find() ? matcher.group(1) : null;
}
}
record User(int id, String name, String email) {}
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