go 案例2 web项目搭建加数据库
2022年1月7日1. 使用自带模板引擎 html/template
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package main import ( "fmt" "github.com/gorilla/mux" "html/template" "net/http" "net/url" "strings" "unicode/utf8" ) var router = mux.NewRouter() type ArticlesFormData struct { Title, Body string URL *url.URL Errors map[string]string } /** * 中间键方法 */ func forceHTMLMiddleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.Header().Set("Content-Type", "text/html; charset=utf-8") //1.设置标头 h.ServeHTTP(w, r) //2.继续处理请求 }) } func homeHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "<h1>Hello, 欢迎来到 goblog！</h1>") } func aboutHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "此博客是用以记录编程笔记，如您有反馈或建议，请联系 <a href=\"mailto:summer@example.com\">summer@example.com</a>") } func notFoundHandler(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "<h1>请求页面未找到 :(</h1><p>如有疑惑，请联系我们。</p>") } func articlesShowHandler(w http.ResponseWriter, r *http.Request) { vars := mux.Vars(r) id := vars["id"] fmt.Fprint(w, "文章 ID："+id) } func articlesIndexHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "访问文章列表") } func articlesStoreHandler(w http.ResponseWriter, r *http.Request) { title := r.PostFormValue("title") body := r.PostFormValue("body") errors := make(map[string]string) // 验证标题 if title == "" { errors["title"] = "标题不能为空" } else if utf8.RuneCountInString(title) < 3 || utf8.RuneCountInString(title) > 40 { errors["title"] = "标题长度需介于 3-40" } // 验证内容 if body == "" { errors["body"] = "内容不能为空" } else if utf8.RuneCountInString(body) < 10 { errors["body"] = "内容长度需大于或等于 10 个字节" } // 检查是否有错误 if len(errors) == 0 { fmt.Fprint(w, "验证通过!<br>") fmt.Fprintf(w, "title 的值为: %v <br>", title) fmt.Fprintf(w, "title 的长度为: %v <br>", utf8.RuneCountInString(title)) fmt.Fprintf(w, "body 的值为: %v <br>", body) fmt.Fprintf(w, "body 的长度为: %v <br>", utf8.RuneCountInString(body)) } else { html := ` <!DOCTYPE html> <html lang="en"> <head> <title>创建文章 —— 我的技术博客</title> <style type="text/css">.error {color: red;}</style> </head> <body> <form action="{{ .URL }}" method="post"> <p><input type="text" name="title" value="{{ .Title }}"></p> {{ with .Errors.title }} <p class="error">{{ . }}</p> {{ end }} <p><textarea name="body" cols="30" rows="10">{{ .Body }}</textarea></p> {{ with .Errors.body }} <p class="error">{{ . }}</p> {{ end }} <p><button type="submit">提交</button></p> </form> </body> </html> ` storeURL, _ := router.Get("articles.store").URL() data := ArticlesFormData{ Title: title, Body: body, URL: storeURL, Errors: errors, } tmpl, err := template.New("create-form").Parse(html) if err != nil { panic(err) } err = tmpl.Execute(w, data) if err != nil { panic(err) } } } /** * 创建文章页面 */ func articlesCreateHandler(w http.ResponseWriter, r *http.Request) { html := ` <!DOCTYPE html> <html lang="en"> <head> <title>创建文章 —— 我的技术博客</title> </head> <body> <form action="%s?test=data" method="post"> <p><input type="text" name="title"></p> <p><textarea name="body" cols="30" rows="10"></textarea></p> <p><button type="submit">提交</button></p> </form> </body> </html> ` storeURL, _ := router.Get("articles.store").URL() //println(storeURL) fmt.Fprintf(w, html, storeURL) } /** * 移除路由后面斜杠的方法 */ func removeTrailingSlash(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { //1. 除首页以外，移除所有请求路径后面的斜杆 if r.URL.Path != "/" { r.URL.Path = strings.TrimSuffix(r.URL.Path, "/") } //2. 将请求传递下去 next.ServeHTTP(w, r) }) } func main() { router.Use(forceHTMLMiddleware) router.HandleFunc("/", homeHandler).Methods("GET").Name("home") router.HandleFunc("/about", aboutHandler).Methods("GET").Name("about") router.HandleFunc("/articles/create", articlesCreateHandler).Methods("GET").Name("articles.create") router.HandleFunc("/articles/{id:[0-9]+}", articlesShowHandler).Methods("GET").Name("articles.show") router.HandleFunc("/articles", articlesIndexHandler).Methods("GET").Name("articles.index") router.HandleFunc("/articles", articlesStoreHandler).Methods("POST").Name("articles.store") router.NotFoundHandler = http.HandlerFunc(notFoundHandler) //自定义 404 页面 http.ListenAndServe(":3000", removeTrailingSlash(router)) } |
案例二
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package main import ( "fmt" "github.com/gorilla/mux" "html/template" "net/http" "net/url" "strings" "unicode/utf8" ) var router = mux.NewRouter() type ArticlesFormData struct { Title, Body string URL *url.URL Errors map[string]string } /** * 中间键方法 */ func forceHTMLMiddleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.Header().Set("Content-Type", "text/html; charset=utf-8") //1.设置标头 h.ServeHTTP(w, r) //2.继续处理请求 }) } func homeHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "<h1>Hello, 欢迎来到 goblog！</h1>") } func aboutHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "此博客是用以记录编程笔记，如您有反馈或建议，请联系 <a href=\"mailto:summer@example.com\">summer@example.com</a>") } func notFoundHandler(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "<h1>请求页面未找到 :(</h1><p>如有疑惑，请联系我们。</p>") } func articlesShowHandler(w http.ResponseWriter, r *http.Request) { vars := mux.Vars(r) id := vars["id"] fmt.Fprint(w, "文章 ID："+id) } func articlesIndexHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "访问文章列表") } /** * 文章提交api */ func articlesStoreHandler(w http.ResponseWriter, r *http.Request) { title := r.PostFormValue("title") body := r.PostFormValue("body") errors := make(map[string]string) //验证标题 if title == "" { errors["title"] = "标题不能为空" } else if utf8.RuneCountInString(title) < 3 || utf8.RuneCountInString(title) > 40 { errors["title"] = "标题长度需介于 3-40" } //验证内容 if body == "" { errors["body"] = "内容不能为空" } else if utf8.RuneCountInString(body) < 10 { errors["body"] = "内容长度需大于或等于 10 个字节" } if len(errors) > 0 { storeURL, _ := router.Get("articles.store").URL() data := ArticlesFormData{ Title: title, Body: body, URL: storeURL, Errors: errors, } tmpl, err := template.ParseFiles("resources/views/articles/create.gohtml") if err != nil { //如果读取模板有错 panic(err) } err = tmpl.Execute(w, data) if err != nil { //如果给模板赋值变量有错 panic(err) } return } fmt.Fprint(w, "验证通过!<br>") fmt.Fprintf(w, "title 的值为: %v <br>", title) fmt.Fprintf(w, "title 的长度为: %v <br>", utf8.RuneCountInString(title)) fmt.Fprintf(w, "body 的值为: %v <br>", body) fmt.Fprintf(w, "body 的长度为: %v <br>", utf8.RuneCountInString(body)) } /** * 创建文章页面 */ func articlesCreateHandler(w http.ResponseWriter, r *http.Request) { storeURL, _ := router.Get("articles.store").URL() data := ArticlesFormData{ Title: "", Body: "", URL: storeURL, Errors: nil, } tmpl, err := template.ParseFiles("resources/views/articles/create.gohtml") if err != nil { panic(err) } err = tmpl.Execute(w, data) if err != nil { panic(err) } } /** * 移除路由后面斜杠的方法 */ func removeTrailingSlash(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { //1. 除首页以外，移除所有请求路径后面的斜杆 if r.URL.Path != "/" { r.URL.Path = strings.TrimSuffix(r.URL.Path, "/") } //2. 将请求传递下去 next.ServeHTTP(w, r) }) } func main() { router.Use(forceHTMLMiddleware) router.HandleFunc("/", homeHandler).Methods("GET").Name("home") router.HandleFunc("/about", aboutHandler).Methods("GET").Name("about") router.HandleFunc("/articles/create", articlesCreateHandler).Methods("GET").Name("articles.create") router.HandleFunc("/articles/{id:[0-9]+}", articlesShowHandler).Methods("GET").Name("articles.show") router.HandleFunc("/articles", articlesIndexHandler).Methods("GET").Name("articles.index") router.HandleFunc("/articles", articlesStoreHandler).Methods("POST").Name("articles.store") router.NotFoundHandler = http.HandlerFunc(notFoundHandler) //自定义 404 页面 http.ListenAndServe(":3000", removeTrailingSlash(router)) } |
3一个完整的增删改查
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package main import ( "database/sql" "fmt" "github.com/go-sql-driver/mysql" _ "github.com/go-sql-driver/mysql" //匿名导入 "github.com/gorilla/mux" "log" "net/http" "net/url" "strconv" "strings" "text/template" "time" "unicode/utf8" ) var db *sql.DB //定义数据库链接 var router = mux.NewRouter() //定义路由 /** * 定义一个数据格式 */ type Article struct { Title, Body string ID int64 } /** * 定义一个数据格式 */ type ArticlesFormData struct { Title, Body string URL *url.URL Errors map[string]string } /** * RouteName2URL 通过路由名称来获取 URL */ func RouteName2URL(routeName string, pairs ...string) string { url, err := router.Get(routeName).URL(pairs...) if err != nil { checkError(err) return "" } return url.String() } /** * Int64ToString 将 int64 转换为 string */ func Int64ToString(num int64) string { return strconv.FormatInt(num, 10) } /** * Link 方法用来生成文章链接 */ func (a Article) Link() string { showURL, err := router.Get("articles.show").URL("id", strconv.FormatInt(a.ID, 10)) if err != nil { checkError(err) return "" } return showURL.String() } /** * 添加删除方法 */ func (a Article) Delete() (rowsAffected int64, err error) { rs, err := db.Exec("DELETE FROM articles WHERE id = " + strconv.FormatInt(a.ID, 10)) if err != nil { return 0, err } // √ 删除成功，跳转到文章详情页 if n, _ := rs.RowsAffected(); n > 0 { return n, nil } return 0, nil } /** * 检查数据是有错的方法 */ func checkError(err error) { if err != nil { log.Fatal(err) return } } /** * 数据库链接的方法 */ func initDB() { var err error config := mysql.Config{ User: "root", Passwd: "123456", Addr: "127.0.0.1:3306", Net: "tcp", DBName: "goblog", AllowNativePasswords: true, } db, err = sql.Open("mysql", config.FormatDSN()) checkError(err) //准备数据库连接池 db.SetMaxOpenConns(25) //设置最大连接数 db.SetMaxIdleConns(25) //设置最大空闲连接数 db.SetConnMaxLifetime(5 * time.Minute) //设置每个链接的过期时间 err = db.Ping() checkError(err) //尝试连接，失败会报错 } /** * 创建表的方法 */ func createTables() { createArticlesSQL := `CREATE TABLE IF NOT EXISTS articles( id bigint(20) PRIMARY KEY AUTO_INCREMENT NOT NULL, title varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL, body longtext COLLATE utf8mb4_unicode_ci ); ` _, err := db.Exec(createArticlesSQL) checkError(err) } /** * DB 创建文章 */ func saveArticleToDB(title string, body string) (int64, error) { //变量初始化 var ( id int64 err error rs sql.Result stmt *sql.Stmt ) stmt, err = db.Prepare("INSERT INTO articles (title, body) VALUES(?,?)") //获取一个 prepare 声明语句 checkError(err) //检查错误 defer stmt.Close() //在此函数运行结束后关闭此语句，防止占用 SQL 连接 rs, err = stmt.Exec(title, body) //执行请求，传参进入绑定的内容 checkError(err) //检查所悟 //插入成功的话，会返回自增 ID if id, err = rs.LastInsertId(); id > 0 { return id, nil } return 0, err } /** * 数据验证 */ func validateArticleFormData(title string, body string) map[string]string { errors := make(map[string]string) // 验证标题 if title == "" { errors["title"] = "标题不能为空" } else if utf8.RuneCountInString(title) < 3 || utf8.RuneCountInString(title) > 40 { errors["title"] = "标题长度需介于 3-40" } // 验证内容 if body == "" { errors["body"] = "内容不能为空" } else if utf8.RuneCountInString(body) < 10 { errors["body"] = "内容长度需大于或等于 10 个字节" } return errors } /** * 中间键方法 */ func forceHTMLMiddleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.Header().Set("Content-Type", "text/html; charset=utf-8") //1.设置标头 h.ServeHTTP(w, r) //2.继续处理请求 }) } /** * 404 页 */ func notFoundHandler(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "<h1>请求页面未找到 :(</h1><p>如有疑惑，请联系我们。</p>") } /** * 首页 */ func homeHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "<h1>Hello, 欢迎来到 goblog！</h1>") } /** * 关于我们页面 */ func aboutHandler(w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "此博客是用以记录编程笔记，如您有反馈或建议，请联系 <a href=\"mailto:summer@example.com\">summer@example.com</a>") } /** * 文章首页 */ func articlesIndexHandler(w http.ResponseWriter, r *http.Request) { // 1. 执行查询语句，返回一个结果集 rows, err := db.Query("SELECT * from articles") checkError(err) defer rows.Close() var articles []Article //2. 循环读取结果 for rows.Next() { var article Article // 2.1 扫描每一行的结果并赋值到一个 article 对象中 err := rows.Scan(&article.ID, &article.Title, &article.Body) checkError(err) // 2.2 将 article 追加到 articles 的这个数组中 articles = append(articles, article) } // 2.3 检测遍历时是否发生错误 err = rows.Err() checkError(err) // 3. 加载模板 tmpl, err := template.ParseFiles("resources/views/articles/index.gohtml") checkError(err) // 4. 渲染模板，将所有文章的数据传输进去 err = tmpl.Execute(w, articles) checkError(err) } /** * 文章创建页面 */ func articlesCreateHandler(w http.ResponseWriter, r *http.Request) { storeURL, _ := router.Get("articles.store").URL() data := ArticlesFormData{ Title: "", Body: "", URL: storeURL, Errors: nil, } tmpl, err := template.ParseFiles("resources/views/articles/create.gohtml") checkError(err) err = tmpl.Execute(w, data) checkError(err) } /** * 获取文章数据 */ func getArticleData(w http.ResponseWriter, r *http.Request) (Article, string, error) { //获取 URL 参数 vars := mux.Vars(r) id := vars["id"] //读取对应的文章数据 article := Article{} query := "SELECT * FROM articles WHERE id = ?" err := db.QueryRow(query, id).Scan(&article.ID, &article.Title, &article.Body) return article, id, err } /** * 文章详情页 */ func articlesShowHandler(w http.ResponseWriter, r *http.Request) { article, _, err := getArticleData(w, r) //如果出现错误 if err != nil { if err == sql.ErrNoRows { //数据未找到 w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "404 文章未找到") } else { //数据库错误 checkError(err) w.WriteHeader(http.StatusInternalServerError) fmt.Fprint(w, "500 服务器内部错误") } return } //读取成功，显示文章 tmpl, err := template.New("show.gohtml").Funcs(template.FuncMap{ "RouteName2URL": RouteName2URL, "Int64ToString": Int64ToString, }).ParseFiles("resources/views/articles/show.gohtml") checkError(err) err = tmpl.Execute(w, article) checkError(err) } /** * 文章编辑页面 */ func articlesEditHandler(w http.ResponseWriter, r *http.Request) { article, id, err := getArticleData(w, r) // 3. 如果出现错误 if err != nil { if err == sql.ErrNoRows { // 3.1 数据未找到 w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "404 文章未找到") } else { // 3.2 数据库错误 checkError(err) w.WriteHeader(http.StatusInternalServerError) fmt.Fprint(w, "500 服务器内部错误") } return } // 4. 读取成功，显示表单 updateURL, _ := router.Get("articles.update").URL("id", id) data := ArticlesFormData{ Title: article.Title, Body: article.Body, URL: updateURL, Errors: nil, } tmpl, err := template.ParseFiles("resources/views/articles/edit.gohtml") checkError(err) err = tmpl.Execute(w, data) checkError(err) } /** * 文章创建api */ func articlesStoreHandler(w http.ResponseWriter, r *http.Request) { title := r.PostFormValue("title") body := r.PostFormValue("body") errors := validateArticleFormData(title, body) if len(errors) > 0 { storeURL, _ := router.Get("articles.store").URL() data := ArticlesFormData{ Title: title, Body: body, URL: storeURL, Errors: errors, } tmpl, err := template.ParseFiles("resources/views/articles/create.gohtml") checkError(err) err = tmpl.Execute(w, data) checkError(err) return } lastInsertID, err := saveArticleToDB(title, body) if lastInsertID == 0 { checkError(err) w.WriteHeader(http.StatusInternalServerError) fmt.Fprint(w, "500 服务器内部错误") return } indexURL, _ := router.Get("articles.index").URL() http.Redirect(w, r, indexURL.String(), http.StatusFound) } /** * 文章更新api */ func articlesUpdateHandler(w http.ResponseWriter, r *http.Request) { // 1. 获取 URL 参数 _, id, err := getArticleData(w, r) // 3. 如果出现错误 if err != nil { if err == sql.ErrNoRows { // 3.1 数据未找到 w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "404 文章未找到") } else { // 3.2 数据库错误 checkError(err) w.WriteHeader(http.StatusInternalServerError) fmt.Fprint(w, "500 服务器内部错误") } return } // 4.1 表单验证 title := r.PostFormValue("title") body := r.PostFormValue("body") errors := validateArticleFormData(title, body) if len(errors) > 0 { // 4.3 表单验证不通过，显示理由 updateURL, _ := router.Get("articles.update").URL("id", id) data := ArticlesFormData{ Title: title, Body: body, URL: updateURL, Errors: errors, } tmpl, err := template.ParseFiles("resources/views/articles/edit.gohtml") checkError(err) err = tmpl.Execute(w, data) checkError(err) } // 4.2 表单验证通过，更新数据 query := "UPDATE articles SET title = ?, body = ? WHERE id = ?" rs, err := db.Exec(query, title, body, id) if err != nil { checkError(err) w.WriteHeader(http.StatusInternalServerError) fmt.Fprint(w, "500 服务器内部错误") } // √ 更新成功，跳转到文章详情页 if n, _ := rs.RowsAffected(); n > 0 { showURL, _ := router.Get("articles.show").URL("id", id) http.Redirect(w, r, showURL.String(), http.StatusFound) } else { fmt.Fprint(w, "您没有做任何更改！") } } /** * 文章删除api */ func articlesDeleteHandler(w http.ResponseWriter, r *http.Request) { //1读取对应的文章数据 article, _, err := getArticleData(w, r) //2如果出现错误 if err != nil { if err == sql.ErrNoRows { // 3.1 数据未找到 w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "404 文章未找到") } else { // 3.2 数据库错误 checkError(err) w.WriteHeader(http.StatusInternalServerError) fmt.Fprint(w, "500 服务器内部错误") } return } //3未出现错误，执行删除操作 rowsAffected, err := article.Delete() //4发生错误 if err != nil { // 应该是 SQL 报错了 checkError(err) w.WriteHeader(http.StatusInternalServerError) fmt.Fprint(w, "500 服务器内部错误") return } //5未发生错误 if rowsAffected == 0 { // Edge case w.WriteHeader(http.StatusNotFound) fmt.Fprint(w, "404 文章未找到") } //6重定向到文章列表页 indexURL, _ := router.Get("articles.index").URL() http.Redirect(w, r, indexURL.String(), http.StatusFound) } /** * 移除路由后面斜杠的方法 */ func removeTrailingSlash(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { //1. 除首页以外，移除所有请求路径后面的斜杆 if r.URL.Path != "/" { r.URL.Path = strings.TrimSuffix(r.URL.Path, "/") } //2. 将请求传递下去 next.ServeHTTP(w, r) }) } /** * 主方法写到里面就会调用执行 */ func main() { initDB() //初始化数据库 createTables() //创建表 router.Use(forceHTMLMiddleware) router.HandleFunc("/", homeHandler).Methods("GET").Name("home") router.HandleFunc("/about", aboutHandler).Methods("GET").Name("about") router.HandleFunc("/articles/create", articlesCreateHandler).Methods("GET").Name("articles.create") router.HandleFunc("/articles/{id:[0-9]+}/edit", articlesEditHandler).Methods("GET").Name("articles.edit") router.HandleFunc("/articles/{id:[0-9]+}", articlesUpdateHandler).Methods("POST").Name("articles.update") router.HandleFunc("/articles/{id:[0-9]+}", articlesShowHandler).Methods("GET").Name("articles.show") router.HandleFunc("/articles", articlesIndexHandler).Methods("GET").Name("articles.index") router.HandleFunc("/articles", articlesStoreHandler).Methods("POST").Name("articles.store") router.HandleFunc("/articles/{id:[0-9]+}/delete", articlesDeleteHandler).Methods("POST").Name("articles.delete") router.NotFoundHandler = http.HandlerFunc(notFoundHandler) //自定义 404 页面 http.ListenAndServe(":3000", removeTrailingSlash(router)) } |
