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PostMapping Spring 引導注釋不起作用

[英]PostMapping Spring boot annotation is not working

 原文  2020-04-09 04:36:57  7   3    java/ spring/ spring-boot/ spring-mvc

問題描述

我是 spring 啟動的新手，不知道為什么我的 @PostMapping 不起作用並導致白色 label 錯誤。 其他一切正常，我可以將客戶添加到 h2 數據庫。 但是，一旦我將客戶和 go 添加到 URL localhost:8084/getdetails 並輸入 1，就會出現白色 label 錯誤。 但是，ViewCustomers.jsp 文件中的表單仍會顯示，但無法接受任何輸入。 該表單應調用客戶 object 及其字段的 toString()。

Controller

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class FormController {
  @Autowired
  CustomerRepo repo;

  @RequestMapping("/")
  public String details() {
    return "edureka";
  }

  @RequestMapping("/details")
  public String details(Customers customers) {
    repo.save(customers);
    return "edureka";
  }

  @RequestMapping("/getdetails")
  public String getdetails() {
    return "ViewCustomers";
  }

  @PostMapping("/getdetails")
  public ModelAndView getdetails(@RequestParam int cid) {
    System.out.println("here");
    ModelAndView mv = new ModelAndView("Retrieve");
    Customers customers = repo.findById(cid).orElse(null);
    mv.addObject(customers);
    return mv;
  }
}

edureka.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Edureka Customers</title>
</head>
<body>
    <form method="post" action="details">
        Enter Customer ID: <input type="text" name="cid"><br><br>
        Enter Customer Name: <input type="text" name="cname"><br><br>    
        Enter Customer Email Address: <input type="email" name="cemail"><br><br>
        <input type="submit" value="Submit">
    </form>
</body>
</html>

查看Customer.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <h1>View Customer Details</h1>
    <h2>Details as submitted as follows</h2>
    <form method="getdetails" action="post">
        <input type="number" name="cid"><br> 
        <input type="submit" value="Submit">
    </form>
</body>
</html>

檢索.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <h1>Retrieve Customer Details</h1>
    <h2>Details as submitted as follows:</h2>
    <h5>${customers}</h5>
</body>
</html>

客戶.java

package com.example.demo;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Customers {
  @Id
  private int cid;
  private String cname;
  private String cemail;

  public int getCid() {
    return cid;
  }

  public void setCid(int cid) {
    this.cid = cid;
  }

  public String getCname() {
    return cname;
  }

  public void setCname(String cname) {
    this.cname = cname;
  }

  public String getCemail() {
    return cemail;
  }

  public void setCemail(String cemail) {
    this.cemail = cemail;
  }

  @Override
  public String toString() {
    return "Customers [cid=" + cid + ", cname=" + cname + ", cemail=" + cemail + "]";
  }
}

CustomerRepo 接口 package com.example.demo；

import org.springframework.data.repository.CrudRepository;

public interface CustomerRepo extends CrudRepository<Customers,Integer>{

}

提交表格Application.java

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.annotation.ComponentScan;
import com.example.demo.SubmissionFormApplication;

@ComponentScan
@SpringBootApplication
public class SubmissionFormApplication extends SpringBootServletInitializer{
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
      return application.sources(SubmissionFormApplication.class);
    }
    public static void main(String[] args) {
        SpringApplication.run(SubmissionFormApplication.class, args);
    }

}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.13.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>SubmissionForm</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>SubmissionForm</name>
    <description>First Spring Boot Web app</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jersey</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web-services</artifactId>
        </dependency>

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper -->
        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-jasper</artifactId>
            <version>9.0.31</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

3 個解決方案

解決方案1
 2  2020-04-09 04:44:16

ViewCustomer.jsp表單的 Method 應該有method as post和action as get details 。 問題出在 html 而不是 spring 中。

解決方案2
 1  2020-04-09 17:30:07

一些東西：

  1. 您的 Controller 可以像@RestController一樣注釋，而不僅僅是@Controller 。

  2. 您的POST映射是@PostMapping - 為了保持一致性，我建議您的GET映射為@GetMapping - 所以我會將所有@RequestMapping替換為@GetMapping （這消除了歧義並提高了可讀性）

  3. 您的eureka.jsp中的表格，需要更改 URL 發布到。 而不是action=details它應該指向action=getdetails

  4. 您視圖中的表單viewcustomer.jsp有動作和帖子切換（方法應該是POST動作應該是getdetails ）

解決方案3
 0  2020-04-09 04:43:58

@PostMapping("/getdetails")映射到路徑"/getdetails" 。 這樣的映射已經存在。 嘗試將 map 轉移到另一條路徑以解決此沖突。

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