源码解读心得 - net.sf.hibernate.util.BytesHelper
//$Id: BytesHelper.java,v 1.4 2003/06/15 12:45:08 oneovthafew Exp $
package net.sf.hibernate.util;
/**
* 此类封装了Array的一些相关操作
*/
public final class BytesHelper {
private BytesHelper() {}
// 转换到int
public static int toInt( byte[] bytes ) {
int result = 0;
for (int i=0; i<4; i++) {
result = ( result << 8 ) - Byte.MIN_VALUE + (int) bytes[i];
}
return result;
}
// 转换到short
public static short toShort( byte[] bytes ) {
return (short) ( ( ( - (short) Byte.MIN_VALUE + (short) bytes[0] ) << 8 ) - (short) Byte.MIN_VALUE + (short) bytes[1] );
}
// int转换到byte数组
public static byte[] toBytes(int value) {
byte[] result = new byte[4];
for (int i=3; i>=0; i--) {
result[i] = (byte) ( ( 0xFFl & value ) + Byte.MIN_VALUE );
value >>>= 8;
}
return result;
}
// short转换到byte数组
public static byte[] toBytes(short value) {
byte[] result = new byte[2];
for (int i=1; i>=0; i--) {
result[i] = (byte) ( ( 0xFFl & value ) + Byte.MIN_VALUE );
value >>>= 8;
}
return result;
}
//以下为测试代码
public static void main( String[] args ) {
System.out.println( 0 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(0) ) );
System.out.println( 1 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(1) ) );
System.out.println( -1 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(-1) ) );
System.out.println( Integer.MIN_VALUE +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MIN_VALUE) ) );
System.out.println( Integer.MAX_VALUE +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MAX_VALUE) ) );
System.out.println( Integer.MIN_VALUE / 2 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MIN_VALUE / 2) ) );
System.out.println( Integer.MAX_VALUE / 2 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MAX_VALUE / 2) ) );
}
}
package net.sf.hibernate.util;
/**
* 此类封装了Array的一些相关操作
*/
public final class BytesHelper {
private BytesHelper() {}
// 转换到int
public static int toInt( byte[] bytes ) {
int result = 0;
for (int i=0; i<4; i++) {
result = ( result << 8 ) - Byte.MIN_VALUE + (int) bytes[i];
}
return result;
}
// 转换到short
public static short toShort( byte[] bytes ) {
return (short) ( ( ( - (short) Byte.MIN_VALUE + (short) bytes[0] ) << 8 ) - (short) Byte.MIN_VALUE + (short) bytes[1] );
}
// int转换到byte数组
public static byte[] toBytes(int value) {
byte[] result = new byte[4];
for (int i=3; i>=0; i--) {
result[i] = (byte) ( ( 0xFFl & value ) + Byte.MIN_VALUE );
value >>>= 8;
}
return result;
}
// short转换到byte数组
public static byte[] toBytes(short value) {
byte[] result = new byte[2];
for (int i=1; i>=0; i--) {
result[i] = (byte) ( ( 0xFFl & value ) + Byte.MIN_VALUE );
value >>>= 8;
}
return result;
}
//以下为测试代码
public static void main( String[] args ) {
System.out.println( 0 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(0) ) );
System.out.println( 1 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(1) ) );
System.out.println( -1 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(-1) ) );
System.out.println( Integer.MIN_VALUE +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MIN_VALUE) ) );
System.out.println( Integer.MAX_VALUE +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MAX_VALUE) ) );
System.out.println( Integer.MIN_VALUE / 2 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MIN_VALUE / 2) ) );
System.out.println( Integer.MAX_VALUE / 2 +"=="+ BytesHelper.toInt( BytesHelper.toBytes(Integer.MAX_VALUE / 2) ) );
}
}
心得:
为什么测试不用单元测试呢,真是不明白。