就是java的类库可以通过doc文档得到信息!
比如String 类查看doc api文档课看到
Constructor Summary
String()
Initializes a newly created String object so that it represents an empty character sequence.
String(byte[] bytes)
Construct a new String by converting the specified array of bytes using the platform's default character encoding.
String(byte[] ascii, int hibyte)
Deprecated. This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a character-encoding name or that use the platform's default encoding.
String(byte[] bytes, int offset, int length)
Construct a new String by converting the specified subarray of bytes using the platform's default character encoding.
String(byte[] ascii, int hibyte, int offset, int count)
Deprecated. This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a character-encoding name or that use the platform's default encoding.
String(byte[] bytes, int offset, int length, String enc)
Construct a new String by converting the specified subarray of bytes using the specified character encoding.
String(byte[] bytes, String enc)
Construct a new String by converting the specified array of bytes using the specified character encoding.
String(char[] value)
Allocates a new String so that it represents the sequence of characters currently contained in the character array argument.
String(char[] value, int offset, int count)
Allocates a new String that contains characters from a subarray of the character array argument.
String(String original)
Initializes a newly created String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string.
String(StringBuffer buffer)
Allocates a new string that contains the sequence of characters currently contained in the string buffer argument.
比如String 类查看doc api文档课看到
Constructor Summary
String()
Initializes a newly created String object so that it represents an empty character sequence.
String(byte[] bytes)
Construct a new String by converting the specified array of bytes using the platform's default character encoding.
String(byte[] ascii, int hibyte)
Deprecated. This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a character-encoding name or that use the platform's default encoding.
String(byte[] bytes, int offset, int length)
Construct a new String by converting the specified subarray of bytes using the platform's default character encoding.
String(byte[] ascii, int hibyte, int offset, int count)
Deprecated. This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a character-encoding name or that use the platform's default encoding.
String(byte[] bytes, int offset, int length, String enc)
Construct a new String by converting the specified subarray of bytes using the specified character encoding.
String(byte[] bytes, String enc)
Construct a new String by converting the specified array of bytes using the specified character encoding.
String(char[] value)
Allocates a new String so that it represents the sequence of characters currently contained in the character array argument.
String(char[] value, int offset, int count)
Allocates a new String that contains characters from a subarray of the character array argument.
String(String original)
Initializes a newly created String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string.
String(StringBuffer buffer)
Allocates a new string that contains the sequence of characters currently contained in the string buffer argument.
API是类的成员函数而已
就是类库对外的接口。这是各类程序设计语言中通用的名词。
JAVA API指的就是JDK的API,当然还有许多第三方提供的其他JAVA类库的API
在左下框中选String