SpringBoot实战3

通过PageBean的实体对象将对应的分页信息作为Result结果展示出来

@RequestParam(required = false) Integer categoryId说明的是这个参数不是必须的

//TODO:文章条件分页查询 @GetMapping public Result<PageBean<Article>> list( Integer pageNum, Integer pageSize, @RequestParam(required = false) Integer categoryId, @RequestParam(required = false) String state ){ PageBean<Article> pageBean=articleService.list(pageNum,pageSize,categoryId,state); return Result.success(pageBean); }

PageHelper.startPage(pageNum,pageSize);参数一为需要查询的页码，参数二为查询的条数

3、调用mapper查询分页数据（UserId从ThredLocal中获取）返回为一个List

List

articles =articleMapper.list(userId,categoryId,state);

4、通过Page中的方法获取PageHelper分页查询之后的总记录数和当前页的数据
Page

page= (Page

) articles; //TODO:设置pageBean的属性，将数据封装到pageBean中 pageBean.setTotal(page.getTotal()); pageBean.setItems(page.getResult());

@Override
public PageBean<Article> list(Integer pageNum, Integer pageSize, Integer categoryId, String state) {
    //TODO:创建pageBean对象
    PageBean<Article> pageBean=new PageBean<>();
    //TODO:开启分页查询
    PageHelper.startPage(pageNum,pageSize);
    //TODO:调用mapper查询分页数据
    Map<String, Object> map = ThreadLocalUtil.get();
    Integer userId= (Integer) map.get("id");
    List<Article> articles =articleMapper.list(userId,categoryId,state);
    //TODO:通过Page中的方法获取PageHelper分页查询之后的总记录数和当前页的数据
    Page<Article> page= (Page<Article>) articles;
    //TODO:设置pageBean的属性，将数据封装到pageBean中
    pageBean.setTotal(page.getTotal());
    pageBean.setItems(page.getResult());
    return pageBean;
}

Mapper层：由于参数categoryId，参数state可以写也可以不写，那么可以使用动态SQL的形式进行查询操作—》书写对应的Mapper映射文件

List<Article> list(Integer userId, Integer categoryId, String state);

com/example/mapper/ArticleMapper.xml

二、获取文章详情

Controller层：

//TODO:获取文章详情
@GetMapping("/detail")
public Result<Article> detail(@RequestParam Integer id){
    Article article=articleService.detail(id);
    return Result.success(article);
}

Service层：

@Override
public Article detail(Integer id) {
    return articleMapper.detail(id);
}

Mapper层：

@Select("select * from article where id=#{id}")
Article detail(Integer id);

三、修改文章

Controller层：对于传入的实体对象参数进行参数校验通过分组校验的形式进行

//TODO:修改文章
@PutMapping
public Result update(@RequestBody @Validated(Article.Update.class) Article article){
    articleService.update(article);
    return Result.success();
}

定义分组校验的实现–》在article中

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Article {
    @NotNull(groups = {Update.class})
    private Integer id;//主键ID
    @NotEmpty
    //1~10个非空字符
    @Pattern(regexp = "^\\S{1,10}$",groups = {Add.class})
    private String title;//文章标题
    @NotEmpty
    private String content;//文章内容
    @NotEmpty
    @URL(groups = {Add.class})
    private String coverImg;//封面图像
    @NotEmpty
    //状态只能为已发布或者草稿
    //@Pattern(regexp = "^(已发布|草稿)$")
    @State
    private String state;//发布状态 已发布|草稿
    @NotNull
    private Integer categoryId;//文章分类id
    private Integer createUser;//创建人ID
    private LocalDateTime createTime;//创建时间
    private LocalDateTime updateTime;//更新时间

    public interface Add extends Default{}

    public interface Update extends Default{}
}

Service层：

@Override
public void update(Article article) {
    //更新文章时间
    article.setUpdateTime(LocalDateTime.now());
    articleMapper.update(article);
}

Mapper层：

@Update("update article set title=#{title},content=#{content},cover_img=#{coverImg},state=#{state},category_id=#{categoryId},update_time=#{updateTime} where id=#{id}")
void update(Article article);

四、删除文章

Controller层：

//TODO:删除文章
@DeleteMapping
public Result delete(@RequestParam Integer id){
    articleService.delete(id);
    return Result.success();
}

Service层

@Override
public void delete(Integer id) {
    articleMapper.delete(id);
}

Mapper层：

@Delete("delete from article where id=#{id}")
void delete(Integer id);

五、文件上传

关于文件上传的操作前端需要实现的部分是

1、提交方式为**Post**

2、提交的表单类型为**multipart/form-data**

3、表单项的类型为**file**

后端通过**MultipartFile类作为请求的参数**来实现文件上传操作

FileUploadController：将图片上传到本地transferTo(转存为一个新的图片文件)

@RestController
public class FIleUploadController {
    @PostMapping("/upload")
    public Result<String> upload(MultipartFile file) throws IOException {
        //TODO:将文件内容存储到本地磁盘上
            // TODO:获取文件名
        String originalFilename=file.getOriginalFilename();
        // TODO:需要保证文件名不重复--》防止文件因为重名而被覆盖
        // TODO:获取文件后缀--截取点后面的文件类型
        String endName=originalFilename.substring(originalFilename.lastIndexOf("."));
        String fileName= UUID.randomUUID().toString()+endName;
        file.transferTo(new File("D:\\桌面\\课程\\workspace\\big-event\\files\\"+fileName));
        return Result.success("url访问地址");
    }
}

将图片上传到阿里云–云端服务器，这样就能在网页直接访问图片了

OSS对象储存服务（可以通过网络在线存储和调用文本，图片，音频，视频等各种文件）

云服务通用思路

一、准备工作

注册登录实名认证
服务充值
开通对象存储服务（OSS）
创建Bucket（存储空间–》存储对象，文件的容器）
获取AccessKey(密钥)–》携带密钥进行上传

二、参照官方的SDK（软件开发工具包）编写入门程序

public class Demo {

    public static void main(String[] args) throws Exception {
        // Endpoint以华北2（北京）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-beijing.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        //EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        String ACCESS_KEY_ID = "yourKeyId";
        String ACCESS_KEY_SECRET = "yourKeySecret";
        // 使用DefaultCredentialProvider方法直接设置AK和SK
        CredentialsProvider credentialsProvider = new DefaultCredentialProvider(ACCESS_KEY_ID, ACCESS_KEY_SECRET);
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "geishihua-big-event";
        // 填写Object完整路径，完整路径中不能包含Bucket名称，例如001.png
        String objectName = "001.png";
        // 填写Bucket所在地域。以华北2（北京）为例，Region填写为cn-beijing。
        String region = "cn-beijing";

        // 创建OSSClient实例。
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // 填写字符串。
            String content = "Hello OSS，你好世界";

            // 创建PutObjectRequest对象。
            PutObjectRequest putObjectRequest = new PutObjectRequest(bucketName, objectName, new FileInputStream("D:\\桌面\\课程\\springboot3+Vue3\\imgs\\4.png"));

            // 如果需要上传时设置存储类型和访问权限，请参考以下示例代码。
            // ObjectMetadata metadata = new ObjectMetadata();
            // metadata.setHeader(OSSHeaders.OSS_STORAGE_CLASS, StorageClass.Standard.toString());
            // metadata.setObjectAcl(CannedAccessControlList.Private);
            // putObjectRequest.setMetadata(metadata);

            // 上传字符串。
            PutObjectResult result = ossClient.putObject(putObjectRequest);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

三、集成使用—>`将这个OSS上传的功能集成为一个工具类AliOssUtil`

public class AliOssUtil {
    // Endpoint以华北2（北京）为例，其它Region请按实际情况填写。endpoint在这个bucket的概览处中的访问端口的外网访问一栏
    private static final String ENDPOINT = "https://oss-cn-beijing.aliyuncs.com";
    // 填写您的AccessKey ID和AccessKey Secret。
    private static final String ACCESS_KEY_ID = "yourId";
    private static final String ACCESS_KEY_SECRET = "yourSecret";
    // 填写Bucket名称，例如examplebucket。
    private static final String BUCKET_NAME = "yourbucketname";
    // 填写Bucket所在地域。以华北2（北京）为例，Region填写为cn-beijing。
    private static final String REGION = "cn-beijing";
    public static String UploadFile(String objectName, InputStream in) throws Exception {
        // 使用DefaultCredentialProvider方法直接设置AK和SK
        CredentialsProvider credentialsProvider = new DefaultCredentialProvider(ACCESS_KEY_ID, ACCESS_KEY_SECRET);

        // 创建OSSClient实例。
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(ENDPOINT)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(REGION)
                .build();
        String url="";
        try {
            // 填写字符串。
            String content = "Hello OSS，你好世界";

            // 创建PutObjectRequest对象。
            PutObjectRequest putObjectRequest = new PutObjectRequest(BUCKET_NAME, objectName, in);

            // 上传字符串。
            PutObjectResult result = ossClient.putObject(putObjectRequest);

            // 获取上传文件的URL组成：http://BUCKET_NAME.oss-cn-beijing.aliyuncs.com/OBJECT_NAME
            url = "http://" + BUCKET_NAME + ".oss-" + REGION+".aliyuncs.com" + "/" + objectName;
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
        return url;
    }
}

改写将文件上传到本地

@RestController
public class FIleUploadController {
    @PostMapping("/upload")
    public Result<String> upload(MultipartFile file) throws Exception {
        //TODO:将文件内容存储到本地磁盘上
            // TODO:获取文件名
        String originalFilename=file.getOriginalFilename();
        // TODO:需要保证文件名不重复--》防止文件因为重名而被覆盖
        // TODO:获取文件后缀--截取点后面的文件类型
        String endName=originalFilename.substring(originalFilename.lastIndexOf("."));
        String fileName= UUID.randomUUID().toString()+endName;
        //file.transferTo(new File("D:\\桌面\\课程\\workspace\\big-event\\files\\"+fileName));
        //TODO：通过MultipartFile获取文件流--file.getInputStream()
        String url = AliOssUtil.UploadFile(fileName, file.getInputStream());
        return Result.success(url);
    }
}

SpringBoot实战3