java 中getxxx的用法大全

2006-09-28 11:11

Version 1: How to read each JDBC type

This section lists the ResultSet.getXXX methods recommended and allowed for retrieving data of each JDBC type.

TINYINT: getByte (recommended)

Can also be read using getShort, getInt, getLong, getFloat,

getDouble, getBigDecimal, getBoolean, getString, getObject

SMALLINT: getShort (recommended)

Can also be read using getByte, getInt, getLong, getFloat,

getDouble, getBigDecimal, getBoolean, getString, getObject

INTEGER: getInt (recommended)

Can also be read using getByte, getShort, getLong, getFloat, getDouble, getBigDecimal, getBoolean, getString, getObject

BIGINT: getLong (recommended)

Can also be read using getByte, getShort, getInt, getFloat,

getDouble, getBigDecimal, getBoolean, getString, getObject

REAL: getFloat (recommended)

Can also be read using getByte, getShort, getInt, getLong,

getDouble, getBigDecimal, getBoolean, getString, getObject

FLOAT: getDouble (recommended)

Can also be read using getByte, getShort, getInt, getLong,

getFloat, getBigDecimal, getBoolean, getString, getObject

DOUBLE: getDouble (recommended)

Can also be read using getByte, getShort, getInt, getLong,

getFloat, getBigDecimal, getBoolean, getString, getObject

DECIMAL: getBigDecimal (recommended)

Can also be read using getByte, getShort, getInt, getLong, getFloat, getDouble, getBoolean, getString, getObject

NUMERIC: getBigDecimal (recommended)

Can also be read using getByte, getShort, getInt, getLong, getFloat, getDouble, getBoolean, getString, getObject

BIT: getBoolean (recommended)

Can also be read using getByte, getShort, getInt, getLong, getFloat, getDouble, getBigDecimal, getString, getObject

CHAR: getString (recommended)

Can also be read using getByte, getShort, getInt, getLong,

getFloat, getDouble, getBigDecimal, getBoolean, getDate, getTime, getTimestamp, getAsciiStream, getUnicodeStream, getObject

VARCHAR: getString (recommended)

Can also be read using getByte, getShort, getInt, getLong,

getFloat, getDouble, getBigDecimal, getBoolean, getDate, getTime, getTimestamp, getAsciiStream, getUnicodeStream, getObject

LONGVARCHAR: getAsciiStream, getUnicodeStream (both recommended)

Can also be read using getByte, getShort, getInt, getLong, getFloat, getDouble, getBigDecimal, getBoolean, getString, getDate, getTime, getTimestamp, getObject

BINARY: getBytes (recommended)

Can also be read using getString, getAsciiStream,

getUnicodeStream, getBinaryStream, getObject

VARBINARY: getBytes (recommended)

Can also be read using getString, getAsciiStream,

getUnicodeStream, getBinaryStream, getObject

LONGVARBINARY: getBinaryStream (recommended)

Can also be read using getString, getBytes, getAsciiStream,

getUnicodeStream, getObject

DATE: getDate (recommended)

Can also be read using getString, getTimestamp, getObject

TIME: getTime (recommended)

Can also be read using getString, getTimestamp, getObject

TIMESTAMP: getTimestamp (recommended)

Can also be read using getString, getDate, getTime, getObject Version 2: Which types each ResultSet.getXXX method can read This section lists the JDBC types that each ResultSet.getXXX method supports.

getByte: TINYINT (recommended)

Can also read SMALLINT, INTEGER, BIGINT, REAL, FLOAT, DOUBLE, DECIMAL, NUMERIC, BIT, CHAR, VARCHAR, LONGVARCHAR

getShort: SMALLINT (recommended)

Can also read TINYINT, INTEGER, BIGINT, REAL, FLOAT, DOUBLE, DECIMAL, NUMERIC, BIT, CHAR, VARCHAR, LONGVARCHAR

getInt: INTEGER (recommended)

Can also read TINYINT, SMALLINT, BIGINT, REAL, FLOAT, DOUBLE, DECIMAL, NUMERIC, BIT, CHAR, VARCHAR, LONGVARCHAR

getLong: BIGINT (recommended)

Can also read TINYINT, SMALLINT, INTEGER, REAL, FLOAT, DOUBLE, DECIMAL, NUMERIC, BIT, CHAR, VARCHAR, LONGVARCHAR

getFloat: REAL (recommended)

Can also read TINYINT, SMALLINT, INTEGER, BIGINT, FLOAT, DOUBLE, DECIMAL, NUMERIC, BIT, CHAR, VARCHAR, LONGVARCHAR

getDouble: FLOAT, DOUBLE (both recommended)

Can also read TINYINT, SMALLINT, INTEGER, BIGINT, REAL, DECIMAL, NUMERIC, BIT, CHAR, VARCHAR, LONGVARCHAR

getBigDecimal: DECIMAL, NUMERIC (both recommended)

Can also read TINYINT, SMALLINT, INTEGER, BIGINT, REAL, FLOAT, DOUBLE, BIT, CHAR, VARCHAR, LONGVARCHAR

getBoolean: BIT (recommended)

Can also read TINYINT, SMALLINT, INTEGER, BIGINT, REAL, FLOAT, DOUBLE, DECIMAL, NUMERIC, CHAR, VARCHAR, LONGVARCHAR

getString: CHAR, VARCHAR (both recommended)

Can also read TINYINT, SMALLINT, INTEGER, BIGINT, REAL, FLOAT, DOUBLE, DECIMAL, NUMERIC, BIT, LONGVARCHAR, BINARY, VARBINARY, LONGVARBINARY, DATE, TIME, TIMESTAMP

getBytes: BINARY, VARBINARY (both recommended)

Can also read LONGVARBINARY

getDate: DATE (recommended)

Can also read CHAR, VARCHAR, LONGVARCHAR, TIMESTAMP

getTime: TIME (recommended)

Can also read CHAR, VARCHAR, LONGVARCHAR, TIMESTAMP

getTimestamp: TIMESTAMP (recommended)

Can also read CHAR, VARCHAR, LONGVARCHAR, DATE, TIME

getAsciiStream: LONGVARCHAR (recommended)

Can also read CHAR, VARCHAR, BINARY, VARBINARY, LONGVARBINARY

getUnicodeStream: LONGVARCHAR (recommended)

Can also read CHAR, VARCHAR, BINARY, VARBINARY, LONGVARBINARY

getBinaryStream: LONGVARBINARY (recommended)

Can also read BINARY, VARBINARY

getObject: (no recommended type)

Can read TINYINT, SMALLINT, INTEGER, BIGINT, REAL, FLOAT, DOUBLE, DECIMAL, NUMERIC, BIT, CHAR, VARCHAR, LONGVARCHAR, BINARY, VARBINARY, LONGVARBINARY, DATE, TIME, TIMESTAMP

 

第二篇：Java中Interface用法

Java中在接口的应用中，要注意一下几点：

<1>接口一般定义的是常量和一些抽象方法。抽象类中可以包含抽象方法，也可以有非抽象方法，但是有抽象方法的类一定是抽象类。抽象方法不能有方法体。

<2>在引用接口时，接口的引用指向实现的对象，尽量定义为接口或父类的引用。这其中有可能用到多态的知识。引用接口用implements。

<3>接口（interface）只能定义抽象方法而且默认为是Public。常量是public static final 修饰的

<4>通过implements来引用接口。例：Class runnrtmp inplements runner.

<5>多个无关类可以实现一个接口，!!!!接口的引用指向实现的对象。

<6>一个类可以实现多个无关的接口（这点和继承要有所区别）

<7>和继承一样，接口与实现类之间存在多态性。

<8>接口可以继承其他的接口，并添加新的属性和抽象方法。

<9>在类中实现接口的方法时必须加上public修饰符

下面通过一个例子来对上面的要点进行下说明

接口的应用1：

1 interface Runner //定义接口

2 {

3 int i=3;

4 public void start();

5 void run();

6 void stop();

7 }

8 interface Eater extends Runner //接口间可以继承

9 {

10 public final static int j=4;

11 void openMouth();

12 void upAndDown();

13 void goIn();

14 }

15 class TT implements Eater //引用接口

16 {

17 public void start()

18 {

19 System.out.println("---------start()-------"); 20 }

21 public void run()

22 {

23 System.out.println("---------run()-------"); 24 }

25 public void stop()

26 {

27 System.out.println("---------stop()-------"); 28 }

29 public void openMouth()

30 {

31 System.out.println("---------openMouth()-------"); 32 }

33 public void upAndDown()

34 {

35 System.out.println("---------upAndDown()-------"); 36 }

37 public void goIn()

38 {

39 System.out.println("---------goIn()-------"); 40 }

41 }

42 public class TestInterface

43 {

44 public static void main(String[] args)

45 {

46 Runner tt=new TT();//接口的引用指向实现的对象 47 System.out.println(tt.i);

48 System.out.println(Runner.i);

49 tt.start();

50 Eater ee=new TT();

51 System.out.println(ee.j);

52 System.out.println(Eater.j);

53 ee.start();

54 }

55 }

接口的应用2：

1 public class TestInterface {

2

3 public static void main(String[] args){

4

5 CareAnimalable c = new Worker();

6 //Worker w = (Worker)c;

7 TestInterface t = new TestInterface();

8 t.t(c); //多态

9

10 c = new Farmer();

11 t.t(c);

12

13

14 }

15

16 public void t(CareAnimalable c){//尽量定义为接口或父类的引用

17 c.feed();

18 c.play();

19 }

20 }

21

22

23 interface CareAnimalable{

24 public void feed();

25 public void play();

26 }

27

28 class Worker implements CareAnimalable{

29

30 public void feed(){

31 System.out.println("-----feed()----");

32 }

33

34 public void play(){

35 System.out.println("-----play()----");

36 }

37 }

38

39 class Farmer implements CareAnimalable{

40

41 public void feed(){

42 System.out.println("-----Farmer feed()----"); 43 }

44

45 public void play(){

46 System.out.println("-----Farmer play()----"); 47 }

48 }

以上就是接口的用法，在编程开发中我们可以通过定义接口来简便编程。在ANDROID开发中，接口的用处很大，所以希望大家能把接口的知识掌握。