servlet拓展-统一响应json功能、全局异常处理

朴灿烈づ我的快乐病毒、 2023-10-13 08:44 55阅读 0赞

## servlet拓展-统一响应json功能、全局异常处理 ##

#### 一、baseservlet ####

import com.fasterxml.jackson.databind.ObjectMapper;
    import teamwork.com.utils.ApiResult;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.lang.reflect.Method;
    
    public class BaseServlet extends HttpServlet {
        
    
        @Override
        protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        
            String operation = req.getParameter("operation");
            Method[] methods = this.getClass().getDeclaredMethods();
            for (Method method : methods) {
        
                if (method.getName().equals(operation)) {
        
                    try {
        
                        method.invoke(this, req, resp);
                    } catch (Exception e) {
        
                        // 全局异常处理
                        sendJsonResponse(resp, new ApiResult(500, "服务器内部错误", e.getMessage()));
                        e.printStackTrace();
                    }
                }
            }
        }
    
        //    响应json
        protected static void sendJsonResponse(HttpServletResponse response, Object responseObject) throws IOException {
        
            // 使用 ObjectMapper 将 Java 对象转换为 JSON 字符串
            ObjectMapper objectMapper = new ObjectMapper();
            String json = objectMapper.writeValueAsString(responseObject);
    
            // 设置响应的内容类型为 "application/json"
            response.setContentType("application/json");
    
            // 将 JSON 字符串作为响应的内容写入输出流
            PrintWriter out = response.getWriter();
            out.print(json);
            out.flush();
        }
    
    }

#### 二、用法 ####

import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    @WebServlet("/example")
    public class ExampleServlet extends BaseJsonServlet {
        
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        
            // 在这里编写你的业务逻辑，返回一个 Java 对象
            ExampleObject exampleObject = new ExampleObject();
            exampleObject.setId(1);
            exampleObject.setName("John Doe");
            exampleObject.setAge(30);
    
            // 调用父类的方法发送 JSON 响应
            sendJsonResponse(response, exampleObject);
        }
    
    }

![在这里插入图片描述][513afb73c1404507ade13dc7cc2e6508.png]

[513afb73c1404507ade13dc7cc2e6508.png]: https://img-blog.csdnimg.cn/513afb73c1404507ade13dc7cc2e6508.png