日常练习

今天练习在eclipse上使用spring boot写简单程序。
大致目标是完成一个简单的学生成绩系统。
首先是主类：

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {> ``
        SpringApplication.run(DemoApplication.class, args);
    }
}

控制器：

package com.example.demo.controller;

import com.example.demo.entity.Student;
import com.example.demo.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.util.UriComponentsBuilder;

import java.util.Objects;

@Controller
public class StudentController {
    @Autowired
    private StudentService studentService;

    @GetMapping("/")
    public String index(Model model,
                       @RequestParam(required = false) String searchName,
                       @RequestParam(required = false) Boolean onlyPass) {
        model.addAttribute("students", 
            studentService.getFilteredStudents(searchName, onlyPass));
        model.addAttribute("searchName", searchName);
        model.addAttribute("onlyPass", onlyPass);
        return "index";
    }

    @PostMapping("/add")
    public String addStudent(
        @RequestParam("name") String name,        // 明确指定参数名
        @RequestParam("score") Integer score,     // 确保类型匹配
        @RequestParam(required = false) String searchName,
        @RequestParam(required = false) Boolean onlyPass) {
        
        // 添加参数验证
        if (name == null || name.trim().isEmpty()) {
            throw new IllegalArgumentException("姓名不能为空");
        }
        if (score < 0 || score > 100) {
            throw new IllegalArgumentException("分数必须在0-100之间");
        }
        
        studentService.addStudent(name, score);
        return createRedirectUrl(searchName, onlyPass);
    }
    
    @GetMapping("/delete/{id}")
    public String deleteStudent(@PathVariable Long id,
                               @RequestParam(required = false) String searchName,
                               @RequestParam(required = false) Boolean onlyPass) {
        studentService.deleteStudent(id);
        return createRedirectUrl(searchName, onlyPass);
    }

    private String createRedirectUrl(String searchName, Boolean onlyPass) {
        UriComponentsBuilder builder = UriComponentsBuilder.fromPath("/");
        
        if (searchName != null && !searchName.isEmpty()) {
            builder.queryParam("searchName", searchName);
        }
        if (onlyPass != null) {
            builder.queryParam("onlyPass", onlyPass);
        }
        
        return "redirect:" + builder.toUriString();
    }
}

服务类：

package com.example.demo.service;

import com.example.demo.entity.Student;
import org.springframework.stereotype.Service;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;

@Service
public class StudentService {
    private List<Student> students = new ArrayList<>();
    private Long nextId = 1L;

    public List<Student> getFilteredStudents(String searchName, Boolean onlyPass) {
        return students.stream()
            .filter(s -> searchName == null || s.getName().startsWith(searchName))
            .filter(s -> !Boolean.TRUE.equals(onlyPass) || s.getScore() >= 60)
            .collect(Collectors.toList());
    }

    public void addStudent(String name, Integer score) {
        Objects.requireNonNull(name, "姓名不能为null");
        if (score == null) {
            throw new IllegalArgumentException("分数不能为null");
        }
        
        students.add(new Student(nextId++, name, score));
    }

    public void deleteStudent(Long id) {
        students.removeIf(s -> s.getId().equals(id));
    }
}

实体类：

package com.example.demo.entity;

public class Student {
    private Long id;
    private String name;
    private Integer score;

    public Student() {}

    public Student(Long id, String name, Integer score) {
        this.id = id;
        this.name = name;
        this.score = score;
    }

    // Getter & Setter 方法
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getScore() {
        return score;
    }

    public void setScore(Integer score) {
        this.score = score;
    }
}

html文件：
index.html:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>学生成绩管理系统</title>
    <style>
        .red { color: red; }
        table { border-collapse: collapse; margin-top: 20px; }
        th, td { padding: 8px; border: 1px solid #ddd; }
    </style>
</head>
<body>
    <h1>学生成绩管理系统</h1>
    
    <!-- 添加表单 -->
    <form th:action="@{/add}" method="post" onsubmit="return validateForm()">
    <input type="text" name="name" required 
           minlength="2" maxlength="10"
           pattern="[\u4e00-\u9fa5a-zA-Z]+"
           title="姓名只能包含中文或英文字符">
    
    <input type="number" name="score" 
           required min="0" max="100"
           oninvalid="this.setCustomValidity('分数必须在0-100之间')"
           oninput="this.setCustomValidity('')">
    
    <!-- 保留隐藏参数 -->
    <button type="submit">添加学生</button>
	</form>

    <!-- 过滤表单 -->
    <form method="get" style="margin: 20px 0;">
        <input type="text" name="searchName" placeholder="搜索姓氏" 
               th:value="${searchName}">
        <label>
            <input type="checkbox" name="onlyPass" 
                   th:checked="${onlyPass}"> 仅显示及格
        </label>
        <button type="submit">筛选</button>
    </form>
	<script>
function validateForm() {
    const scoreInput = document.querySelector('input[name="score"]');
    if (scoreInput.value < 0 || scoreInput.value > 100) {
        alert("分数必须在0-100之间");
        return false;
    }
    return true;
}
</script>
    <!-- 学生列表 -->
    <div th:if="${#lists.isEmpty(students)}" style="color: #666;">
        暂无学生数据，请添加学生信息
    </div>

    <table th:unless="${#lists.isEmpty(students)}">
        <tr>
            <th>姓名</th>
            <th>分数</th>
            <th>操作</th>
        </tr>
        <tr th:each="student : ${students}">
            <td th:text="${student.name}"></td>
            <td>
                <span th:class="${student.score < 60} ? 'red'" 
                      th:text="${student.score}"></span>
            </td>
            <td>
                <a th:href="@{/delete/{id}(id=${student.id}, 
                            searchName=${searchName}, 
                            onlyPass=${onlyPass})">删除</a>
            </td>
        </tr>
    </table>
</body>
</html>

error.html:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>错误页面</title>
    <style>
        .error-container {
            max-width: 800px;
            margin: 2rem auto;
            padding: 2rem;
            background: #ffe6e6;
            border: 1px solid #ff9999;
            border-radius: 8px;
        }
    </style>
</head>
<body>
    <div class="error-container">
        <h1>⚠️ 发生错误</h1>
        <p th:text="${errorMessage}"></p>
        <a href="/">返回首页</a>
    </div>
</body>
</html>

我目前的练习项目的内容就是如此，我测试时发现无法运行，当点击添加学生时就会直接进入error.html，同时点击返回首页也无济于事。
我猜想错误大概是我的控制器出错了，但不知道具体在哪里，仍在摸索。