Public components of the forum system

1. Create a package under the Java directory and create a folder under the Resources directory. The structure is as follows

├─java # java file area

│ └─com

│ └─example

│ └─demo

│ ├─common # public class

│ ├─config # configuration class

│ ├─controller # Controller layer class

│ ├─dao # Database access class

│ ├─exception # Custom exception class

│ ├─interceptor # Custom interceptor class

│ ├─model # Database entity corresponding model class

│ ├─services # Business service layer interface

│ │ └─impl # Business service layer interface implementation class

│ └─utils # Input tools

└─resources # resource file area

├─mapper # Database and model mapping file

│ └─extension # Extend database and model mapping files, customize business methods

├─mybatis # Mybatis Generator configuration file

├─static # static file

└─templates # template file

2. Create generatorConfig.xml

Create a mybatis directory under src/main/resources, and create a generatorConfig.xml file under the mybatis directory with the following content:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <!-- 驱动包路径，location中路径替换成自己本地路径 -->
    <classPathEntry location="C:\Users\20278\.m2\repository\mysql\mysql-connector-java\5.1.49\mysql-connector-java-5.1.49.jar"/>

    <context id="DB2Tables" targetRuntime="MyBatis3">
        <!-- 禁用自动生成的注释 -->
        <commentGenerator>
            <property name="suppressAllComments" value="true"/>
            <property name="suppressDate" value="true"/>
        </commentGenerator>

        <!-- 连接配置 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1:3306/java_forum?characterEncoding=utf8&amp;useSSL=false"
                        userId="root"
                        password="123456">
        </jdbcConnection>

        <javaTypeResolver>
            <!-- 小数统一转为BigDecimal -->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!-- 实体类生成位置 -->
        <javaModelGenerator targetPackage="com.example.demo.model" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- mapper.xml生成位置 -->
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <!-- DAO类生成位置 -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.example.demo.dao"
                             targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <!-- 配置生成表与实例, 只需要修改表名tableName, 与对应类名domainObjectName 即可-->
        <table tableName="t_article" domainObjectName="Article" enableSelectByExample="false"
               enableDeleteByExample="false" enableDeleteByPrimaryKey="false" enableCountByExample="false"
               enableUpdateByExample="false">
            <!-- 类的属性用数据库中的真实字段名做为属性名, 不指定这个属性会自动转换 _ 为驼峰命名规则-->
            <property name="useActualColumnNames" value="true"/>
        </table>
        <table tableName="t_article_reply" domainObjectName="ArticleReply" enableSelectByExample="false"
               enableDeleteByExample="false" enableDeleteByPrimaryKey="false" enableCountByExample="false"
               enableUpdateByExample="false">
            <property name="useActualColumnNames" value="true"/>
        </table>
        <table tableName="t_board" domainObjectName="Board" enableSelectByExample="false" enableDeleteByExample="false"
               enableDeleteByPrimaryKey="false" enableCountByExample="false" enableUpdateByExample="false">
            <property name="useActualColumnNames" value="true"/>
        </table>
        <table tableName="t_message" domainObjectName="Message" enableSelectByExample="false"
               enableDeleteByExample="false" enableDeleteByPrimaryKey="false" enableCountByExample="false"
               enableUpdateByExample="false">
            <property name="useActualColumnNames" value="true"/>
        </table>
        <table tableName="t_user" domainObjectName="User" enableSelectByExample="false" enableDeleteByExample="false"
               enableDeleteByPrimaryKey="false" enableCountByExample="false" enableUpdateByExample="false">
            <property name="useActualColumnNames" value="true"/>
        </table>
    </context>
</generatorConfiguration>

3. Run the plugin to generate the file

1) Create a mapper directory under src/main/resources

2) Click the image below to reload the Maven project, mybatis-generator appears under the Plugins node, double-click to run, and generate the corresponding class and mapping files in the corresponding directory, as shown in the following image:

4. Add the option to get the primary key value in the Insert tag

<!-- useGeneratedKeys = true -->
<!-- keyProperty = 主键字段--> 
<!-- 当插⼊⼀条数据后，可以通过user.getId()获取到⾃动⽣成的Id值，如果⽅法中需要⽴即获取Id值，加⼊这个配置 --> 
 <insert id="insert" parameterType="com.example.demo.model.Article" useGeneratedKeys="true" keyProperty="id">

5. Add @Mapper annotation

Add @Mapper annotation to each xxxMapper.java under the dao package

package com.example.demo.dao;

import com.example.demo.model.Article;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

import java.util.List;

@Mapper
public interface ArticleMapper {
    int insert(Article row);

    int insertSelective(Article row);

    Article selectByPrimaryKey(Long id);

    int updateByPrimaryKeySelective(Article row);

    int updateByPrimaryKeyWithBLOBs(Article row);

    int updateByPrimaryKey(Article row);
}

6. Create a new MybatisConfig class under the config package and specify the scanning path of Mybatis

package com.example.demo.config;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Configuration;

// 配置类
@Configuration
// 指定Mybatis的扫描路径
@MapperScan("com.example.demo.dao")
public class MybatisConfig {
}

7. Write common code

1) Define the status code

Make a targeted description of the success and failure states that may occur during the execution of business processing logic, use enumeration to define the status code, define a part first, and add it when new problems are encountered in the business

Create an enumeration type named ResultCode under the com.example.demo.common package

package com.example.demo.common;

//枚举类型
public enum ResultCode {
    SUCCESS                   (0, "操作成功"),
    FAILED                    (1000, "操作失败"),
    FAILED_UNAUTHORIZED       (1001, "未授权"),
    FAILED_PARAMS_VALIDATE    (1002, "参数校验失败"),
    FAILED_FORBIDDEN          (1003, "禁止访问"),
    FAILED_CREATE             (1004, "新增失败"),
    FAILED_NOT_EXISTS         (1005, "资源不存在"),
    FAILED_USER_EXISTS        (1101, "用户已存在"),
    FAILED_USER_NOT_EXISTS    (1102, "用户不存在"),
    FAILED_LOGIN              (1103, "用户名或密码错误"),
    FAILED_USER_BANNED        (1104, "您已被禁言, 请联系管理员, 并重新登录."),
    FAILED_TWO_PWD_NOT_SAME   (1105, "两次输入的密码不一致"),

    FAILED_BOARD_NOT_EXISTS   (1201, "版块不存在"),

    FAILED_ARTICLE_NOT_EXISTS (1301, "帖子不存在"),
    FAILED_ARTICLE_STATE      (1302, "帖子状态异常"),
    ERROR_SERVICES            (2000, "服务器内部错误"),
    ERROR_IS_NULL             (2001, "IS NULL.");
    //状态码
    int code;
    //错误描述
    String message;

    ResultCode(int code, String message) {
        this.code = code;
        this.message = message;
    }
    public int getCode() {
        return code;
    }

    public String getMessage() {
        return message;
    }

    @Override
    public String toString() {
        return "code = " + code + ",message = " + message + ".";
    }

}

2) Define the return result

The system realizes the separation of front and back ends, and uniformly returns strings in JSON format. A class needs to be defined, which contains status code, description information, and returned result data

a. Create the AppResult class under the com.example.demo.common package

b. Adding @JsonInclude(JsonInclude.Include.ALWAYS) to the attribute indicates that it must be serialized whether it is empty or not

package com.example.demo.common;

import com.fasterxml.jackson.annotation.JsonInclude;

public class AppResult<T> {

    //自定义状态码
    @JsonInclude(JsonInclude.Include.ALWAYS)
    private int code;
    //描述信息
    @JsonInclude(JsonInclude.Include.ALWAYS)
    private String message;
    //具体返回的数据
    @JsonInclude(JsonInclude.Include.ALWAYS)
    private T data;

    //构造方法
    public AppResult(int code, String message) {
        this.code = code;
        this.message = message;
    }

    public AppResult(int code, String message, T data) {
        this.code = code;
        this.message = message;
        this.data = data;
    }

    //成功方法,泛型方法
    /**
     *
     * @param message  描述信息
     * @param data  具体的数据
     * @return
     * @param <T>
     */
    public static <T> AppResult<T> success(String message,T data){
        return new AppResult<>(ResultCode.SUCCESS.code,message,data);
    }

    public static <T> AppResult<T> success(String message){
        return new AppResult<>(ResultCode.SUCCESS.code,message,null);
    }

    public static <T> AppResult<T> success(T data){
        return new AppResult<>(ResultCode.SUCCESS.getCode(),ResultCode.SUCCESS.getMessage(),data);
    }

    public static AppResult success(){
        return  new AppResult(ResultCode.SUCCESS.getCode(),ResultCode.SUCCESS.getMessage(),null);
    }

    //失败方法
    public static AppResult failed(){
        return new AppResult(ResultCode.FAILED.getCode(),ResultCode.FAILED.getMessage());
    }

    public static AppResult failed(String message){
        return new AppResult(ResultCode.FAILED.getCode(),message);
    }

    public static AppResult failed(ResultCode resultCode){
        return new AppResult(resultCode.getCode(), resultCode.getMessage());
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = data;
    }
}

3) Custom exception

Create an exception class and add status code and status description attributes

Create ApplicationException under com.example.demo.exception package

package com.example.demo.exception;

import com.example.demo.common.AppResult;
import com.example.demo.common.ResultCode;

public class ApplicationException extends RuntimeException{
    //自定义的异常描述
    private AppResult errorResult;

    public ApplicationException(AppResult appResult) {
        //构造异常中的Message属性
        super(appResult.getMessage());
        //自定义的错误描述
        this.errorResult = appResult;
    }

    public ApplicationException(String message) {
        super(message);
        //根据异常描述构建返回对象
        this.errorResult = new AppResult((ResultCode.FAILED.getCode()),message);
    }

    //指定异常
    public ApplicationException(Throwable cause){
        super(cause);
    }

    //自定义异常描述，异常信息
    public ApplicationException(String message,Throwable cause){
        super(message,cause);
    }

    public AppResult getErrorResult() {
        return errorResult;
    }

    public void setErrorResult(AppResult errorResult) {
        this.errorResult = errorResult;
    }
}

4) Global exception handling

Use @ControllerAdvice+@ExceptionHandler annotations to achieve unified exception handling

@ControllerAdvice represents the controller notification class

Create a GlobalExceptionHandler under the com.example.demo.exception package

package com.example.demo.exception;


import com.example.demo.common.AppResult;
import com.example.demo.common.ResultCode;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

@Slf4j
@ControllerAdvice
public class GlobalExceptionHandler {

    //捕获自己的ApplicationException异常
    //以body形式返回
    @ResponseBody
    @ExceptionHandler(ApplicationException.class)
    public AppResult handleApplicationException(ApplicationException e){
        //打印异常，上传线上要注释掉
        e.printStackTrace();
        //记录日志
        log.error(e.getMessage());
        //获取异常信息
        if(e.getErrorResult() != null){
            //返回异常类中记录的状态
            return e.getErrorResult();
        }
        //默认返回异常信息
        return AppResult.failed(e.getMessage());
    }

    /**
     * 处理全部未捕获的其他异常
     * @param e
     * @return
     */

    @ResponseBody
    @ExceptionHandler(Exception.class)
    public AppResult handleException(Exception e){
        //打印异常
        e.printStackTrace();
        //记录日志
        log.error(e.getMessage());
        if(e.getMessage() == null){
            return AppResult.failed(ResultCode.ERROR_SERVICES);
        }
        //默认返回异常信息
        return AppResult.failed(e.getMessage());
    }

}

8. Login interceptor

Create a LoginInterceptor under the interceptor package

package com.example.demo.interceptor;

import com.example.demo.config.AppConfig;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@Component
public class LoginInterceptor implements HandlerInterceptor {

    //从配置文件中获取默认登陆页的URL
    @Value("${java_forum.login.url")
    private String defaultURL;

    /**
     * 请求的前置处理
     * @param request
     * @param response
     * @param handler
     * @return true 校验成功，继续请求流程  <br/>false 中断请求流程
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //获取session，并做已登录用户信息的校验
        HttpSession session = request.getSession(false);
        if(session != null && session.getAttribute(AppConfig.USER_SESSION_KEY) != null){
            //校验通过
            return true;
        }

        //保证跳转页面的路径正确性
        if(!defaultURL.startsWith("/")){
            defaultURL = "/" + defaultURL;
        }
        //校验未通过,跳转到登录页面
        response.sendRedirect(defaultURL);
        //中止请求

        return false;
    }
}

Create AppInterceptorConfigurer under the interceptor package

package com.example.demo.interceptor;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import javax.annotation.Resource;

@Configuration
public class AppInterceptorConfigurer implements WebMvcConfigurer {

    @Resource
    private LoginInterceptor loginInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 添加登录拦截器
        registry.addInterceptor(loginInterceptor)       // 添加用户登录拦截器
                .addPathPatterns("/**")                 // 拦截所有请求
                .excludePathPatterns("/sign-in.html")   // 排除登录HTML
                .excludePathPatterns("/sign-up.html")   // 排除注册HTML
                .excludePathPatterns("/user/login")     // 排除登录api接口
                .excludePathPatterns("/user/register")  // 排除注册api接口
                .excludePathPatterns("/user/logout")    // 排除退出api接口
                .excludePathPatterns("/swagger*/**")    // 排除登录swagger下所有
                .excludePathPatterns("/v3*/**")         // 排除登录v3下所有，与swagger相关
                .excludePathPatterns("/dist/**")        // 排除所有静态文件
                .excludePathPatterns("/image/**")
                .excludePathPatterns("/**.ico")
                .excludePathPatterns("/js/**");
    }
}

9. Implement automatic API generation

Use Springfox Swagger to generate API and import it into Postman to complete API unit test

10. Write configuration class

Create a new SwaggerConfig.java under the com.example.demo.config package

package com.example.demo.config;
import org.springframework.boot.actuate.autoconfigure.endpoint.web.CorsEndpointProperties;
import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointProperties;
import org.springframework.boot.actuate.autoconfigure.web.server.ManagementPortType;
import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
import org.springframework.boot.actuate.endpoint.web.*;
import org.springframework.boot.actuate.endpoint.web.annotation.ControllerEndpointsSupplier;
import org.springframework.boot.actuate.endpoint.web.annotation.ServletEndpointsSupplier;
import org.springframework.boot.actuate.endpoint.web.servlet.WebMvcEndpointHandlerMapping;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.util.StringUtils;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.oas.annotations.EnableOpenApi;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * Swagger配置类
 *
 * @Author 比特就业课
 */
// 配置类
@Configuration
// 开启Springfox-Swagger
@EnableOpenApi
public class SwaggerConfig {

    /**
     * Springfox-Swagger基本配置
     * @return
     */
    @Bean
    public Docket createApi() {
        Docket docket = new Docket(DocumentationType.OAS_30)
                .apiInfo(apiInfo())
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.example.demo.Controller"))
                .paths(PathSelectors.any())
                .build();
        return docket;

    }

    // 配置API基本信息
    private ApiInfo apiInfo() {
        ApiInfo apiInfo = new ApiInfoBuilder()
                .title("论坛系统API")
                .description("论坛系统前后端分离API测试")
                .contact(new Contact("Tech", "https://gitee.com/tanjiawe/java_forum", "[email protected]"))
                .version("1.0")
                .build();
        return apiInfo;
    }

    /**
     * 解决SpringBoot 6.0以上与Swagger 3.0.0 不兼容的问题
     * 复制即可
     **/
    @Bean
    public WebMvcEndpointHandlerMapping webEndpointServletHandlerMapping(WebEndpointsSupplier webEndpointsSupplier,
                                                                         ServletEndpointsSupplier servletEndpointsSupplier,
                                                                         ControllerEndpointsSupplier controllerEndpointsSupplier,
                                                                         EndpointMediaTypes endpointMediaTypes, CorsEndpointProperties corsProperties,
                                                                         WebEndpointProperties webEndpointProperties, Environment environment) {
        List<ExposableEndpoint<?>> allEndpoints = new ArrayList();
        Collection<ExposableWebEndpoint> webEndpoints = webEndpointsSupplier.getEndpoints();
        allEndpoints.addAll(webEndpoints);
        allEndpoints.addAll(servletEndpointsSupplier.getEndpoints());
        allEndpoints.addAll(controllerEndpointsSupplier.getEndpoints());
        String basePath = webEndpointProperties.getBasePath();
        EndpointMapping endpointMapping = new EndpointMapping(basePath);
        boolean shouldRegisterLinksMapping = this.shouldRegisterLinksMapping(webEndpointProperties, environment,
                basePath);
        return new WebMvcEndpointHandlerMapping(endpointMapping, webEndpoints, endpointMediaTypes,
                corsProperties.toCorsConfiguration(), new EndpointLinksResolver(allEndpoints, basePath),
                shouldRegisterLinksMapping, null);
    }

    private boolean shouldRegisterLinksMapping(WebEndpointProperties webEndpointProperties, Environment environment,
                                               String basePath) {
        return webEndpointProperties.getDiscovery().isEnabled() && (StringUtils.hasText(basePath)
                || ManagementPortType.get(environment).equals(ManagementPortType.DIFFERENT));
    }

}

11. Create MD5 encryption tool class

Commons-codec is used in the project, which is a toolkit provided by Apache for digest calculation, encoding and decoding. Common encoding and decoding tools Base64, MD5, Hex, SHA1, DES, etc.

Create the MD5Utils class under the com.example.demo.utils package, the code is as follows:

package com.example.demo.utils;

import org.apache.commons.codec.digest.DigestUtils;

public class MD5Utils {
    /**
     * //返回一个用MD5加密后的字符串
     * @param str 原始字符串
     * @return
     */
    public static String md5(String str){
        return DigestUtils.md5Hex(str);
    }

    /**
     * 明文加盐生成最终的密文
     * @param str 要加密的明文
     * @param salt 盐
     * @return 密文
     */
    public static String md5Salt(String str, String salt){
        //先对明文进行MD5加密
        String s = DigestUtils.md5Hex(str);
        //加密后的原文与盐拼接在一起之后再进行一次MD5加密
        String ciphertext = DigestUtils.md5Hex(s + salt);
        //返回密文
        return ciphertext;
    }
}

12. Create a tool class for generating UUID

Create the UUIDUtils class under the com.example.demo.utils package, the code is as follows:

package com.example.demo.utils;

import java.util.UUID;

public class UUIDUtils {

    /**
     * 生成一个UUID
     * @return
     */
    public static String UUID_36(){
        return UUID.randomUUID().toString();
    }

    /**
     * 生成一个32位的UUID
     * @return
     */
    public static String UUID_32(){
        return UUID.randomUUID().toString().replace("-","");
    }
}

13. Create a string tool class

Create the StringUtils class under the com.example, demo.utils package, the code is as follows:

package com.example.demo.utils;

public class StringUtils {
    /**
     * 校验字符串是否为空
     * @param value 待校验的字符串
     * @return true空，<br/>false非空
     */
    public static boolean isEmpty(String value){
        if(value == null ||value.isEmpty()){
            return true;
        }
        return false;
    }
}

Public components of the forum system

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