Select 从H2中选择“添加”；clob:“；用clojure编辑文本

我正在使用clojure的h2数据库。我做了一张表格，像这样放了一些数据

(j/create-table :locations
    [:id "bigint primary key auto_increment"]
    [:title "varchar (255)"]
    [:part "clob"])

  (j/insert-records :locations
    {:title "Steven Gerrard: I'm not the new Beckham" :part "He might not have the Becks appeal -- but Steven Gerrard says he's ready to light up Hollywood in his own way..."}))
    )
   )

然后我选择了数据

(defn newest []
 (database/mysql-db)
 (let [results (j/with-connection db-spec
                  (j/with-query-results res
                    ["select id, title, part from locations"]
                    (doall res)))]
    results))

我用了clostache页面上的数据

<div class="container">
    <sections>
         {{#newest}}
           <p style="padding-bottom: 15px;">{{title}}<p>
           <p style="padding-bottom: 15px;">{{part}}<p>
         {{/newest}}
     </sections>
  </div>

---

如何删除附加到数据库中文本的

clob0:

字符串？即使我对数据库中的零件列使用

text

而不是

clob

，也会发生这种情况。

我删除了

clob:

：

(defn clob-to-string [row]
  (assoc row :text (with-open [rdr (java.io.BufferedReader. (.getCharacterStream (:text row)))]
    (apply str (line-seq rdr)))))

(defn newest []
 (database/mysql-db)
 (j/query db-spec
          ["select id, title, text from news"]
          :row-fn clob-to-string
    ))

---

“clob0:”前缀实际上并没有附加到数据库中的数据

之所以会出现这种情况，是因为ResultSet为列“part”返回类

java.sql.Clob

的实例（对于Clob和TEXT数据类型，它们实际上都是）

---

使用

toString（）

方法将Clob转换为字符串是不合适的，实现可以自由返回任何人类可读的形式。正确的方法可以在中找到

您可能已经注意到，由于上述原因，新线丢失了。。。像这样的东西又把它们加回来了

(defn clob-to-string [clob]
        "Turn an Clob into a String, with new new lines"
    (with-open [rdr (java.io.BufferedReader. (.getCharacterStream clob))]
      (let [lseq (line-seq rdr)
            butlast-line (butlast lseq)
            butlast-line-mapped (map (fn [l] (str l "\n")) butlast-line)
            last-line (last lseq)
            all-lines-with-newline (concat butlast-line-mapped last-line)
            ]
        (apply str all-lines-with-newline)
        )))

(defn clob-to-string [clob]
        "Turn an Clob into a String, with new new lines"
    (with-open [rdr (java.io.BufferedReader. (.getCharacterStream clob))]
      (let [lseq (line-seq rdr)
            butlast-line (butlast lseq)
            butlast-line-mapped (map (fn [l] (str l "\n")) butlast-line)
            last-line (last lseq)
            all-lines-with-newline (concat butlast-line-mapped last-line)
            ]
        (apply str all-lines-with-newline)
        )))