Multiple line code example in Javadoc comment

I have a small code example I want to include in the Javadoc comment for a method.

/**
 * -- ex: looping through List of Map objects --
 * <code>
 * for (int i = 0; i < list.size(); i++) {
 *      Map map = (Map)list.get(i);
 *      System.out.println(map.get("wordID"));
 *      System.out.println(map.get("word"));
 * }
 * </code>
 * 
 * @param query - select statement
 * @return List of Map objects
 */

The problem is the code example shows up in the Javadoc with no line breaks making it hard to read.

-- ex: looping through List of Map objects -- for (int i = 0; i list.size(); i++) { Map map = (Map)list.get(i); System.out.println(map.get("wordID")); System.out.println(map.get("word")); } 
Parameters
query - - select statement 
Returns:
List of Map objects 

I guess I am wrong in assuming the code tag would handle line breaks. What is the best way to format code examples in Javadoc comments ?

---

In addition to the already mentioned <pre> tags, you should also use the @code JavaDoc annotation, which will make life much easier when it comes to HTML entities issues (in particular with Generics), eg:

* <pre>
* {@code
* Set<String> s;
* System.out.println(s);
* }
* </pre>

Will give correct HTML output:

Set<String> s;
System.out.println(s);

While omitting the @code block (or using a <code> tag) will result in HTML like this:

Set s;
System.out.println(s);

(For reference, Java SE 8 tag descriptions can be found here: Javadoc Tags)

---

I had a really tough time with including a specific code example in a javadoc comment. I'd like to share this one.
Please note the following:

usage of old <code> - tag to prevent the curly brackets from being interpreted

usage of "new" {@code ...} - tag to get the generics included in the output

escaping of the @ sign in @Override via " {@literal @}Override " because javadoc generator "tilts" there due to the fact that the @ goes directly after an opening curly bracket

remove one space in front of {@code and {@literal , to compensate inner spaces and keep the alignment

javadoc code:

/** this methods adds a specific translator from one type to another type. `
  * i.e.
  * <pre>
  * <code>new BeanTranslator.Builder()
  *   .translate(
  *     new{@code Translator<String, Integer>}(String.class, Integer.class){
  *      {@literal @}Override
  *       public Integer translate(String instance) {
  *         return Integer.valueOf(instance);
  *       }})
  *   .build();
  * </code>
  * </pre>
  * @param translator
  */

gets printed as

new BeanTranslator.Builder()
  .translate(
    new Translator<String, Integer>(String.class, Integer.class){
      @Override
      public Integer translate(String instance) {
        return Integer.valueOf(instance);
      }})
  .build();

---

The java source has lots of good examples for this. Here's an example from the head of "String.java":

....
 * is equivalent to:
 * <p><blockquote><pre>
 *     char data[] = {'a', 'b', 'c'};
 *     String str = new String(data);
 * </pre></blockquote><p>
 * Here are some more examples of how strings can be used:
 * <p><blockquote><pre>
 *     System.out.println("abc");
 *     String cde = "cde";
 *     System.out.println("abc" + cde);
 *     String c = "abc".substring(2,3);
 *     String d = cde.substring(1, 2);
 * </pre></blockquote>
...

链接地址: http://www.djcxy.com/p/50198.html

上一篇: 链接到Javadoc中的外部URL？

下一篇: Javadoc评论中有多行代码示例