Java类调用Web服务返回至JSP？温度转换工具开发及代码验证求助

Hey there! Let's break this down step by step to get your JSP-to-Java Web Service integration working smoothly. I'll cover form validation, proper service invocation, and parameter matching so you can connect the dots easily.

1. Validating Your JSP Form #

First, let's make sure your JSP form is set up to pass the right data to your Java class. A solid form should capture the temperature value and the conversion direction (e.g., Fahrenheit → Celsius or vice versa). Here's a tested example:

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <title>Temperature Converter</title>
</head>
<body>
    <h1>Temperature Conversion</h1>
    <form method="POST" action="TemperatureConverterServlet">
        <label for="temperature">Enter Temperature:</label>
        <input type="number" step="0.1" id="temperature" name="temperature" required>
        
        <label for="conversionType">Convert To:</label>
        <select id="conversionType" name="conversionType" required>
            <option value="F_TO_C">Fahrenheit to Celsius</option>
            <option value="C_TO_F">Celsius to Fahrenheit</option>
        </select>
        
        <button type="submit">Convert</button>
    </form>
</body>
</html>

Key checks for your form:

• Use POST method (safer for data submission than GET)
• Name attributes (temperature, conversionType) should match the parameter names your Java class will read
• Include validation (like required and type="number") to ensure valid input
• The action points to your Java servlet/handler class (adjust the name to match your project setup)

2. Correctly Calling the Web Service from Java #

The approach depends on whether your temperature service is SOAP or REST. Let's cover both common scenarios:

Case 1: SOAP Web Service #

If your service uses WSDL (common for enterprise services), use JAX-WS to generate client code first:

1. Run wsimport -keep http://your-service-url?wsdl in your terminal—this creates Java classes for the service.
2. In your handler class, use the generated code to invoke the service:

import com.your.temperature.service.TemperatureService;
import com.your.temperature.service.TemperatureConverter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class TemperatureConverterServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
        // Get form parameters
        double inputTemp = Double.parseDouble(request.getParameter("temperature"));
        String conversionType = request.getParameter("conversionType");
        
        // Initialize SOAP service client
        TemperatureService service = new TemperatureService();
        TemperatureConverter port = service.getTemperatureConverterPort();
        
        // Call the service method (adjust method name/params to match your service)
        double result;
        if ("F_TO_C".equals(conversionType)) {
            result = port.fahrenheitToCelsius(inputTemp);
        } else {
            result = port.celsiusToFahrenheit(inputTemp);
        }
        
        // Pass result back to JSP
        request.setAttribute("result", result);
        try {
            request.getRequestDispatcher("result.jsp").forward(request, response);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Case 2: REST Web Service #

For a REST-based service (using JSON/XML), use HttpURLConnection to send a request:

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class TemperatureConverterServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
        double inputTemp = Double.parseDouble(request.getParameter("temperature"));
        String conversionType = request.getParameter("conversionType");
        
        // Build service URL (adjust to your service's endpoint)
        String serviceUrl = "http://your-rest-service-url/convert?";
        if ("F_TO_C".equals(conversionType)) {
            serviceUrl += "temp=" + inputTemp + "&unit=F";
        } else {
            serviceUrl += "temp=" + inputTemp + "&unit=C";
        }
        
        // Send request and parse response
        URL url = new URL(serviceUrl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        
        BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String resultStr = in.readLine();
        double result = Double.parseDouble(resultStr);
        
        // Forward result to JSP
        request.setAttribute("result", result);
        try {
            request.getRequestDispatcher("result.jsp").forward(request, response);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

3. Ensuring Parameter Matching #

Double-check these critical points to avoid mismatches:

• Your JSP form's name attributes must exactly match the parameter names your Java class reads with request.getParameter()
• The data types must align: if the Web service expects a double for temperature, parse the form string to double (don't pass raw text)
• If the service expects specific values for conversion type (e.g., "F" instead of "F_TO_C"), adjust your form's option values to match exactly

内容的提问来源于stack exchange，提问作者Luiz Wynne