Java review of common class libraries

First, StringBuffer

1. The difference between StringBuffer and string

2. StringBuffer Common methods

StringBuffer buf = new StringBuffer ();

Buf.append ();

Buf.insert ();

Buf.reverse ();

Buf.replace ();

Buf.substring ();

Buf.delete ();

Buf.indexof ();

3. Practical application of StringBuffer

Use the StringBuffer class when you want to modify the contents of a string.

Second, runtime class

1. Learn about the runtime class

2. Using the runtime class to obtain space information for the JVM

GetRuntime ();//static method

Freememory ();

MaxMemory ();

GC ();

exec ();

3. Runtime class and Process class

III. International Procedures

1. Fundamentals of Internationalization procedures

2. Role of resource files

3. Locale Class (Java.util.Locale)

Represents a country's language class

4. ResourceBundle Class (Java.util.ResourceBundle)

Used to access resource files

Getbundle ();

GetString ();

5. Messageformat processing dynamic text (Java.text.MessageFormat)

Formatting a placeholder string for a resource file

Messageformat.format ();

6. Use of resource classes

Internationalization idea: The program and the display are separated, according to different locale designated area to find different resource files and to obtain the corresponding value according to the key value

Iv. System Class

1. Common methods of the system class

All properties and methods in the system class are static

System.exit ();

System.GC ();

System.currenttime ();

System.arraycopy ()

System.getproperties ()

System.getproperty ()

2. Garbage Object Recycling Operations

3. Declaration period for Objects

Five, date Operation class

1. Date class

2. Calendar class

3. Date formatting Operation DateFormat class

Getdateinstance ();

Getdatetimeinstance ();

Format ()

4. SimpleDateFormat the date format operation

Vi. Math and the random class

1. Mathematical manipulation functions in the math class

Methods in the Math class are static methods

MATH.SQRT ()

Math.max ()

Math.min ()

Math.pow ()

Math.Round ()

2. Random class Generation stochastic number

Seven, NumberFormat

1. NumberFormat class for localized digital display

2. DecimalFormat developing a formatting template

Eight, large number of operations

1. BigInteger Operation Large Integer

2. BigDecimal set the number of reserved digits for decimals

Nine, object cloning technology

1. Cloning principle

2. Object class support for cloning

3. The role of the Conable interface

Ten, Arrays

1. Use of the Arrays class

Equals ()

Fill ()

Sort ()

BinarySearch ()

ToString ()

2. Fill and sort operations

Xi. Comparator

1. Use of the comparable comparison interface

2. Basic sorting principle of comparator

Binary Tree Sorting

3. Use of the comparator comparison interface

12, the Observer design mode

1. The role of the observer design pattern

2. Observable class and Observer interface

Observable:setchanged (); Notifyobservers ();

Observer:update (O,arg)

13. Regular Expressions

1. The role of regular expressions

2. Matching pattern of regular expressions

Pattern.compile (). Matcher (). Matches ()

3. Use of the pattern class and the Matcher class

Java.util.regex in Bag

The main function of pattern class is to write regular specification: Compile (); Matcher (); split ()

Matcher class is mainly the implementation of the Code: matches (); ReplaceAll ();

4. String support for regular expressions: matches (); ReplaceAll (); split ()

14, timing scheduling

1. The role of timing scheduling

Schedule () VS scheduleatfixedrate ()

2. Timer class and TimerTask class

Java review of common class libraries