fix: 修复若干问题，添加java lsp

backend/Dockerfile

@@ -1,22 +1,88 @@
-FROM golang:1.25-alpine AS builder
+# syntax=docker/dockerfile:1
+###############################################################################
+# All-in-one LSP Gateway Image
+#   - Go        → gopls
+#   - JS / TS   → typescript-language-server
+#   - Java      → Eclipse JDT Language Server (jdtls) + JDK 22
+###############################################################################
 
+# ── Stage 1: Build Go gateway binary ────────────────────────────────────────
+FROM golang:1.25-bookworm AS builder
 WORKDIR /src
-
 COPY go.mod go.sum ./
 RUN go mod download
-
 COPY . .
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -trimpath -ldflags="-s -w" -o /out/server ./cmd/server
+RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -ldflags="-s -w" -o /out/server ./cmd/server
 
-FROM alpine:3.20
+# ── Stage 2: Build gopls ────────────────────────────────────────────────────
+FROM golang:1.25-bookworm AS gopls-builder
+RUN go install golang.org/x/tools/gopls@latest
 
-RUN addgroup -S app && adduser -S -G app app
+# ── Stage 3: Runtime ────────────────────────────────────────────────────────
+FROM eclipse-temurin:22-jdk-noble
 
+ARG NODE_MAJOR=22
+
+# ---- System deps: Node.js, python3 (jdtls launcher) ----
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends ca-certificates curl python3 && \
+    curl -fsSL https://deb.nodesource.com/setup_${NODE_MAJOR}.x | bash - && \
+    apt-get install -y --no-install-recommends nodejs && \
+    rm -rf /var/lib/apt/lists/*
+
+# ---- typescript-language-server (covers JavaScript + TypeScript) ----
+RUN npm install -g typescript-language-server typescript && \
+    npm cache clean --force
+
+# ---- Go toolchain (gopls needs it at runtime for analysis) ----
+COPY --from=golang:1.25-bookworm /usr/local/go /usr/local/go
+ENV PATH="/usr/local/go/bin:/go/bin:${PATH}" \
+    GOPATH="/go"
+
+# ---- gopls ----
+COPY --from=gopls-builder /go/bin/gopls /go/bin/gopls
+
+# ---- Eclipse JDT Language Server ----
+COPY jdt-language-server-1.57.0-202602111032 /opt/jdtls
+RUN chmod +x /opt/jdtls/bin/jdtls /opt/jdtls/bin/jdtls.py
+
+# ---- Gateway binary ----
 WORKDIR /app
 COPY --from=builder /out/server /app/server
 COPY config.example.json /app/config.example.json
 
-ENV PORT=8080
+# ---- Default config: all 4 LSP servers, Redis/Nacos off by default ----
+COPY <<'EOF' /app/config.json
+{
+  "port": "8080",
+  "workspaceDir": "/workspace",
+  "allowOrigin": "*",
+  "requestTimeout": "30s",
+  "sessionTTL": "20m",
+  "cleanupInterval": "2m",
+  "maxSessions": 256,
+  "enableRedis": false,
+  "enableNacosRegister": false,
+  "appEnv": "prod",
+  "logLevel": "info",
+  "logConsoleEnabled": true,
+  "servers": [
+    { "language": "go",         "languageId": "go",         "command": "gopls",                     "args": [] },
+    { "language": "javascript", "languageId": "javascript", "command": "typescript-language-server", "args": ["--stdio"] },
+    { "language": "typescript", "languageId": "typescript", "command": "typescript-language-server", "args": ["--stdio"] },
+    { "language": "java",       "languageId": "java",       "command": "/opt/jdtls/bin/jdtls",      "args": [] }
+  ]
+}
+EOF
+
+# ---- Directories & non-root user ----
+RUN mkdir -p /workspace /go && \
+    groupadd --system app && \
+    useradd --system --gid app --home-dir /home/app --create-home app && \
+    chown -R app:app /app /workspace /go /home/app
+
+ENV PORT=8080 \
+    WORKSPACE_DIR=/workspace
 EXPOSE 8080
 
 USER app