From 85cdfe9ea1c4a712fc0fa795588ff6f3e2de5b46 Mon Sep 17 00:00:00 2001
From: Jerry Yan <792602257@qq.com>
Date: Tue, 28 Oct 2025 17:31:08 +0800
Subject: [PATCH] =?UTF-8?q?feat(printer):=20=E5=AE=9E=E7=8E=B0=E6=89=93?=
 =?UTF-8?q?=E5=8D=B0=E6=9C=BA=E8=BD=AE=E8=AF=A2=E9=80=89=E6=8B=A9=E5=8A=9F?=
 =?UTF-8?q?=E8=83=BD?=
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- 新增 getNextPrinter 方法实现打印机轮询逻辑
- 添加 Redis 键前缀 PRINTER_INDEX_KEY_PREFIX 和过期时间常量
- 在创建打印任务时设置选中的打印机名称- 支持多个打印机按顺序轮流使用
- 使用 Redis 原子递增确保并发安全的索引获取
- 自动为 Redis 键设置 5 分钟过期时间以避免内存泄漏
---
 .../printer/impl/PrinterServiceImpl.java      | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/src/main/java/com/ycwl/basic/service/printer/impl/PrinterServiceImpl.java b/src/main/java/com/ycwl/basic/service/printer/impl/PrinterServiceImpl.java
index 4b58f875..391551de 100644
--- a/src/main/java/com/ycwl/basic/service/printer/impl/PrinterServiceImpl.java
+++ b/src/main/java/com/ycwl/basic/service/printer/impl/PrinterServiceImpl.java
@@ -444,6 +444,8 @@ public class PrinterServiceImpl implements PrinterService {
     @Autowired
     private RedisTemplate<String, String> redisTemplate;
     private static final String USER_PHOTO_LIST_TO_PRINTER = "USER_PHOTO_LIST_TO_PRINTER:";
+    private static final String PRINTER_INDEX_KEY_PREFIX = "PRINTER_INDEX:";
+    private static final int PRINTER_INDEX_EXPIRE_MINUTES = 5;
     private static final int TASK_STATUS_PENDING = 0;
     private static final int TASK_STATUS_PROCESSING = 3;
     private final Lock syncTaskLock = new ReentrantLock();
@@ -559,8 +561,12 @@ public class PrinterServiceImpl implements PrinterService {
                 log.error("获取景区配置失败，使用原始照片进行打印。景区ID: {}, 照片ID: {}", item.getScenicId(), item.getId(), e);
             }
 
+            // 获取打印机名称（支持轮询）
+            String selectedPrinter = getNextPrinter(printer);
+
             PrintTaskEntity task = new PrintTaskEntity();
             task.setPrinterId(printer.getId());
+            task.setPrinterName(selectedPrinter);
             task.setMpId(item.getId());
             task.setPaper(printer.getPreferPaper());
             task.setStatus(0);
@@ -572,4 +578,52 @@ public class PrinterServiceImpl implements PrinterService {
             printTaskMapper.insertTask(task);
         });
     }
+
+    /**
+     * 获取下一个要使用的打印机名称（轮询逻辑）
+     * 
+     * @param printer 打印机实体
+     * @return 选中的打印机名称
+     */
+    private String getNextPrinter(PrinterEntity printer) {
+        String usePrinter = printer.getUsePrinter();
+        if (StringUtils.isBlank(usePrinter)) {
+            log.warn("打印机 {} 没有配置 usePrinter", printer.getId());
+            return "";
+        }
+
+        // 分割打印机列表
+        String[] printers = usePrinter.split("\\|");
+        if (printers.length == 0) {
+            log.warn("打印机 {} 的 usePrinter 配置为空", printer.getId());
+            return "";
+        }
+
+        // 如果只有一个打印机，直接返回
+        if (printers.length == 1) {
+            return printers[0].trim();
+        }
+
+        // 从 Redis 原子递增获取索引
+        String redisKey = PRINTER_INDEX_KEY_PREFIX + printer.getId();
+        Long incrementedValue = redisTemplate.opsForValue().increment(redisKey);
+        
+        if (incrementedValue == null) {
+            log.warn("Redis increment 操作失败，打印机ID: {}", printer.getId());
+            incrementedValue = 1L;
+        }
+        
+        // 每次递增后都重新设置过期时间为 5 分钟
+        redisTemplate.expire(redisKey, PRINTER_INDEX_EXPIRE_MINUTES, TimeUnit.MINUTES);
+        
+        // 对打印机数量取模得到当前索引
+        int currentIndex = (int) ((incrementedValue - 1) % printers.length);
+        
+        // 获取当前打印机
+        String selectedPrinter = printers[currentIndex].trim();
+
+        log.debug("打印机 {} 选择了第 {} 个打印机: {} (递增值: {})", printer.getId(), currentIndex, selectedPrinter, incrementedValue);
+
+        return selectedPrinter;
+    }
 }