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將Spring Boot Web應用程序連接到postgresql服務器

[英]Connecting Spring Boot web app to a postgresql server

 原文  2015-10-06 02:23:22  0   2    java/ postgresql/ spring-mvc/ jpa/ spring-boot

問題描述

我正在使用Spring Boot創建一個Web應用程序，並且我通過使用內存數據庫（H2）獲得了我想要的功能，但我無法將其連接到我在計算機上設置的postgresql服務器。 我已經有一段時間了，並嘗試了一些不起作用的東西，所以我把所有東西都重新設置為讓它再次運行的方式。

這是我的UploadController.java，它處理從服務器上傳並將其放入我的內存數據庫中： 

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
import project.service.MediaFile;
import project.service.MediaFileRepository;

@Controller
public class UploadController {

    @Autowired
    private MediaFileRepository repository;

    @RequestMapping(value = "/uploadmedia", method = RequestMethod.GET)
    public String uploadForm() {
        return "upload";
    }

    @RequestMapping(value = "/uploadmedia", method = RequestMethod.POST)
    public String uploadSubmit(@RequestParam(value="files[]") MultipartFile[] files,
                               @RequestParam("tags") String tags, @RequestParam("type") String type)
    {
        String[] tagsArray = tags.split("\\s+");
        MultipartFile file;
        String name;
        String tag;
        String path;

        for (int i = 0; i < files.length; i++) {
            file = files[i];
            name = file.getOriginalFilename();
            path = "/Users/johannesthorkell/Developer/spring_prufa/images/" + name;
            System.out.println(name);

            if (!file.isEmpty()) {
                try {
                    byte[] bytes = file.getBytes();
                    BufferedOutputStream stream =
                            new BufferedOutputStream(new FileOutputStream(new File(path)));
                    stream.write(bytes);
                    stream.close();
                    for (int j = 0; j < tagsArray.length; j++) {
                        tag = tagsArray[j].toLowerCase();
                        repository.save(new MediaFile(name, tag, path, type));
                    }
                    System.out.println("Success!");
                } catch (Exception e) {
                    System.out.println("Failure... " + e.getMessage());
                }
            } else {
                System.out.println("No file");
            }
        }
        return "upload";
    }
}

...這是我的MediaFile類，@ Entity對象： 

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class MediaFile {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long id;
    private String name;
    private String tag;
    private String resource;
    private String type;

    protected MediaFile() {}

    public MediaFile(String name, String tag, String resource, String type) {
        this.name = name;
        this.tag = tag;
        this.resource = resource;
        this.type = type;
    }

    public String getTag() {
        return tag;
    }

    @Override
    public String toString() {
        return String.format(
                "MediaFile[id=%d, name='%s', tag='%s', resource='%s', type='%s']",
                id, name, tag, resource, type);
    }

}

...這是我的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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>HBV501G</groupId>
    <artifactId>Spring_Web_MVC</artifactId>
    <version>0.1</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.5.RELEASE</version>
    </parent>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>

    </dependencies>

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

</project>

...最后，這是application.properties： 

spring.view.prefix=/WEB-INF/jsp/
spring.view.suffix=.jsp
multipart.maxFileSize=-1

有了這個設置，一切正常。 我嘗試將以下內容放在我的application.properties中： 

spring.datasource.url=jdbc:postgresql://localhost/test
spring.datasource.username=myusername
spring.datasource.password=mypassword
spring.datasource.driver-class-name=org.postgresql.jdbc.Driver

...以及向pom.xml添加以下依賴項： 

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>9.4-1200-jdbc41</version>
</dependency>

...然后我嘗試混合和匹配這些東西和閱讀教程幾個小時無濟於事。

編輯：

我刪除了一行並添加了另一行（根據StéphaneNic​​oll的建議）所以現在我的application.properties看起來像這樣： 

spring.view.prefix=/WEB-INF/jsp/
spring.view.suffix=.jsp
multipart.maxFileSize=-1
debug=true

spring.datasource.url=jdbc:postgresql://localhost:5432/mydb
spring.datasource.username=username
spring.datasource.password=password

...而我的pom.xml看起來像這樣： 

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>HBV501G</groupId>
    <artifactId>Spring_Web_MVC</artifactId>
    <version>0.1</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.5.RELEASE</version>
    </parent>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>9.4-1200-jdbc41</version>
        </dependency>

        <!--<dependency>-->
            <!--<groupId>com.h2database</groupId>-->
            <!--<artifactId>h2</artifactId>-->
        <!--</dependency>-->

    </dependencies>

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

</project>

隨着我的application.properties的更改我的應用程序現在運行！ 但是當我將POST表單提交給UploadController.java時，我收到以下錯誤： 

2015-10-06 11:32:14.878  INFO 22287 --- [           main] project.Application                      : Started Application in 11.897 seconds (JVM running for 12.971)
2015-10-06 11:32:40.263  INFO 22287 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2015-10-06 11:32:40.264  INFO 22287 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2015-10-06 11:32:40.295  INFO 22287 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 31 ms
hopaskipting.pdf
2015-10-06 11:32:49.752 DEBUG 22287 --- [nio-8080-exec-3] org.hibernate.SQL                        : select nextval ('hibernate_sequence')
2015-10-06 11:32:49.760  WARN 22287 --- [nio-8080-exec-3] o.h.engine.jdbc.spi.SqlExceptionHelper   : SQL Error: 0, SQLState: 42P01
2015-10-06 11:32:49.760 ERROR 22287 --- [nio-8080-exec-3] o.h.engine.jdbc.spi.SqlExceptionHelper   : ERROR: relation "hibernate_sequence" does not exist
  Position: 17
Failure... could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet

我將GenerationType更改為IDENTITY並獲得以下錯誤： 

2015-10-06 12:56:32.496 DEBUG 22746 --- [nio-8080-exec-7] org.hibernate.SQL                        : insert into media_file (name, resource, tag, type) values (?, ?, ?, ?)
2015-10-06 12:56:32.505 DEBUG 22746 --- [nio-8080-exec-7] org.hibernate.SQL                        : insert into media_file (name, resource, tag, type) values (?, ?, ?, ?)
Failure... A different object with the same identifier value was already associated with the session : [project.service.MediaFile#0]; nested exception is javax.persistence.EntityExistsException: A different object with the same identifier value was already associated with the session : [project.service.MediaFile#0]

2 個解決方案

解決方案1
 4 已采納  2015-10-06 12:13:33

錯誤的關鍵部分是： 

2015-10-06 11:32:49.760 ERROR 22287 --- [nio-8080-exec-3] o.h.engine.jdbc.spi.SqlExceptionHelper   : ERROR: relation "hibernate_sequence" does not exist

Hibernate正在尋找一個名為hibernate_sequence的表來支持MediaFile @GeneratedValue 。 您目前已使用AUTO配置它。 然后，實際行為會根據您使用的數據庫而有所不同。

我想你有幾個選擇：

  1. 在Postgres（ CREATE SEQUENCE ）中創建一個名為hibernate_sequence CREATE SEQUENCE
  2. 更改為使用其他生成類型，例如GenerationType.IDENTITY

解決方案2
 0  2015-10-06 06:34:22

如果我是你，我會創建自己的dataSource bean，如： 

@Configuration
public class MyConfig{

    @Autowired
    Environment env;

    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName(env.getProperty("myapp.dataSource.driver"));
        dataSource.setUrl(env.getProperty("myapp.dataSource.url"));
        dataSource.setUsername(env.getProperty("myapp.dataSource.username"));
        dataSource.setPassword(env.getProperty("myapp.dataSource.password"));
        return dataSource;
    }
}

application.properties： 

logging.level. = INFO

myapp.dataSource.driver = 
myapp.dataSource.url = 
myapp.dataSource.username = 
myapp.dataSource.password =

如果您不想嘗試此操作，可以嘗試將驅動程序org.postgresql.jdbc.Driver更改為org.postgresql.Driver 。

沒有任何日志，很難幫助。

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