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PromptTemplate

PromptTemplate 使用 {{placeholder}} 语法进行变量替换，类似 Spring 的 JdbcTemplate。

PromptTemplate template = new PromptTemplate("Tell me a {{adjective}} joke about {{topic}}");
Prompt prompt = template.create(Map.of(
    "adjective", "funny",
    "topic", "programming"
));
ChatResponse response = chatClient.call(prompt);

模板文件

推荐将模板放在 resources/prompts/ 目录下：

# resources/prompts/summary.st
Please summarize the following text in {{language}}.
Keep the summary within {{maxWords}} words.

Text: "{{text}}"

Summary:

// 加载模板文件
PromptTemplate template = new PromptTemplate("classpath:/prompts/summary.st");

Prompt prompt = template.create(Map.of(
    "language", "Chinese",
    "maxWords", "100",
    "text", longText
));

String summary = chatClient.call(prompt).getResult().getOutput().getContent();

复杂模板示例

代码审查模板

# resources/prompts/code-review.st
You are a senior Java code reviewer. Review the following code.
Focus on: {{focusAreas}}

Code:
```java
{{code}}

Please provide:

1. Potential bugs (if any)
2. Code style issues
3. Performance suggestions
4. Security concerns

Answer in .

```java
PromptTemplate template = new PromptTemplate("classpath:/prompts/code-review.st");
Prompt prompt = template.create(Map.of(
    "focusAreas", "performance, security",
    "code", sourceCode,
    "language", "Chinese"
));

String review = chatClient.call(prompt).getResult().getOutput().getContent();

SQL 生成模板

# resources/prompts/sql-gen.st
You are a SQL expert. Convert the following natural language query to {{dialect}} SQL.

Database schema:
{{schema}}

User request: {{userQuery}}

Rules:
- Return ONLY the SQL query, no explanations
- Use proper table aliases
- Add comments for complex logic

Prompt 模板与 System Message 结合

String systemText = """
    You are a {{role}} assistant.
    Always answer in {{language}}.
    Use {{tone}} tone.
    """;

String userText = """
    User question: {{question}}
    """;

PromptTemplate systemTemplate = new PromptTemplate(systemText);
PromptTemplate userTemplate = new PromptTemplate(userText);

Prompt prompt = new Prompt(List.of(
    new SystemMessage(systemTemplate.render(Map.of(
        "role", "technical",
        "language", "Chinese",
        "tone", "professional"
    ))),
    new UserMessage(userTemplate.render(Map.of(
        "question", "What is Spring AI?"
    )))
));

默认系统 Prompt

在 Builder 中结合模板：

@Bean
public ChatClient chatClient(ChatClient.Builder builder) {
    return builder
        .defaultSystem("""
            You are a {{role}} assistant.
            Answer in {{language}}.
            Be {{tone}} and concise.
            """)
        .build();
}

小结

• PromptTemplate 使用 {{var}} 语法做变量替换，支持从 String 和 classpath 文件加载。
• 模板文件放在 resources/prompts/ 下统一管理。
• 复杂场景可用 System + User 多个模板组合。
• 模板中可嵌入示例代码和结构化输出要求。
• 分离 Prompt 模板与 Java 代码，便于维护和调试。

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贡献者: 布欧-Lewyon