http断点续传简单实现（java)

/* n4XMN\:g{  
**SiteFileFetch.java Tu'E{Hw  
*/ 7j95"mI  
package NetFox; :(RL8  
import java.io.*; <EOg,"F  
import java.net.*; IwnYJp:9v  
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public class SiteFileFetch extends Thread { n<+~ zQ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean WY3_7k8u  
long[] nStartPos; //开始位置 U0zW9jB  
long[] nEndPos; //结束位置 UzN8G$92qF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B\NcCp`5  
long nFileLength; //文件长度 @!,D%]8"  
boolean bFirst = true; //是否第一次取文件 (c 1u{  
boolean bStop = false; //停止标志 XZ;*>(  
File tmpFile; //文件下载的临时信息 :Z]/Q/$  
DataOutputStream output; //输出到文件的输出流 @s3aR*ny$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +-'`Q Ae  
public SiteFileFetch(SiteInfoBean bean) throws IOException |zg=+  
{ XZ!cW=bqS  
siteInfoBean = bean; 7-(>"75Q|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e|35|I '  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \}n !yYh(  
if(tmpFile.exists ()) {W]bU{%.  
{ v5P*<U Ax  
bFirst = false;
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read_nPos(); r
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} ,WzG.3^m  
else JIB?dIN 1  
{ qW+=g]x\  
nStartPos = new long[bean.getNSplitter()]; HarYV :  
nEndPos = new long[bean.getNSplitter()]; vRq=m8  
} [`cdlx?Eh  
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} `\nON  
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public void run() \=$EmHF  
{ zK[ 7:<  
//获得文件长度 5/zf x  
//分割文件 fpI;`s  
//实例FileSplitterFetch >2FAi.,  
//启动FileSplitterFetch线程 pE~9o 9  
//等待子线程返回 $@5%5  
try{ j\%?<2dj=  
if(bFirst) 1y_fQ+\2A  
{ +"TI_tK,S  
nFileLength = getFileSize(); dxk;@Tz  
if(nFileLength == -1) " &_$V@S  
{ _K*\}un2  
System.err.println("File Length is not known!"); EY,;e\7O,  
} )w^GPlh  
else if(nFileLength == -2) [u,hc/PL  
{ ~%D^Ga7  
System.err.println("File is not access!"); jdV .{8@  
} CM+F7#T?n  
else nNd`]F^U  
{ Q$/V)0  
for(int i=0;i<nStartPos.length;i++) +9Xu"OFm  
{ ey'pm\Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a3b2nAIl  
} u^j8 XOT  
for(int i=0;i<nEndPos.length-1;i++) a!TBk=P  
{ 8<E!rn-  
nEndPos = nStartPos[i+1]; 4r68`<mn[  
} 6M O|s1zk  
nEndPos[nEndPos.length-1] = nFileLength; 3ybK6!g`[  
} @&!=m]D*  
} U)O?| VN^o  
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,6S_&<{  
//启动子线程 o|z
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; JL}hOBqfI  
for(int i=0;i<nStartPos.length;i++) {mCKTyN+  
{ [ t>}SE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aYv'H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UE}8Rkt  
nStartPos,nEndPos,i); Jdk3) \  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bIvJs9L  
fileSplitterFetch.start(); uzzWZ9Tv  
} yv6Zo0s<J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mq|A8>g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BK`Q)[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0~PXa(!^K  
nEndPos = " + nFileLength); I?^Q084  
// fileSplitterFetch[nPos.length-1].start(); 3D 4]yR5  
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//等待子线程结束 ^g}gT-l%  
//int count = 0; :,xyVb+  
//是否结束while循环 ^P3g9'WK  
boolean breakWhile = false; .(P@Bl]XJ  
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while(!bStop) Ak%no3:9  
{ b@{%qh,C  
write_nPos(); 2|T|K?R^  
Utility.sleep(500); *_2O*{V  
breakWhile = true; GY0XWUlC  
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for(int i=0;i<nStartPos.length;i++) PsF- 9&_  
{ @1J51< x  
if(!fileSplitterFetch.bDownOver) z$I[kR%I{  
{ N+C%Z[gt[  
breakWhile = false; >Rl
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break; ]noP  
} Et@=Ic^E  
} rA1zyZlz  
if(breakWhile) ^5FJ}MMJf  
break; ,Do$`yO+  
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\ pe[V~F  
//count++; 36x5q 1  
//if(count>4) .dg 4gr\D  
// siteStop(); xy-$v   
} #G[ *2h~99  
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System.err.println("文件下载结束！"); N>cp>&j
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} oneSgJ  
catch(Exception e){e.printStackTrace ();} I;Z`!u:+  
} >~^mIu_BH  
v ,G-k2$Qe  
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//获得文件长度 OxmlzQ"vM  
public long getFileSize() N$ qNe'b  
{ @> +^<  
int nFileLength = -1; pZ@W6}  
try{ /`j K  
URL url = new URL(siteInfoBean.getSSiteURL()); OGE#wG"S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t`Y1.]@U  
httpConnection.setRequestProperty("User-Agent","NetFox"); Lv,ji_  
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int responseCode=httpConnection.getResponseCode(); kw}ISXz v  
if(responseCode>=400) 9Ww=hfb5UW  
{ *'`3]!A  
processErrorCode(responseCode); lo>-}xd  
return -2; //-2 represent access is error 9m#H24{V'  
} 9+N._u  
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String sHeader; ![X.%  
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for(int i=1;;i++) mAYr
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{ )z4kP09  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !5' 8a5  
//Utility.log(in.readLine()); I")"
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sHeader=httpConnection.getHeaderFieldKey(i); @$b+~X)7  
if(sHeader!=null) um_M}t{  
{ go%X%Os]  
if(sHeader.equals("Content-Length")) nkCRe  
{ ./BP+\)lO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *~t$k56  
break; (X`t"*y"  
} *`pec3"  
} 3MBz  
else P7BJ?x  
break; ru6HnLhL  
} t+4%,n f_1  
} iK6<^,]'  
catch(IOException e){e.printStackTrace ();} z}b U\3!  
catch(Exception e){e.printStackTrace ();} zOdasEd8!  
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Utility.log(nFileLength); CgTQGJ}-  
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return nFileLength; v_1JH<GJ-  
} b#\kZ/W  
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//保存下载信息（文件指针位置） UNZVu~WnF  
private void write_nPos() P".qL5  
{ $nD k mKl  
try{ ~]_jKe4W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ReGO9}  
output.writeInt(nStartPos.length); K~hlwjrt  
for(int i=0;i<nStartPos.length;i++) EJ &ZZg  
{ ^x1D]+  
// output.writeLong(nPos); x+)hL D[ n  
output.writeLong(fileSplitterFetch.nStartPos); <4A(Z$ZX)  
output.writeLong(fileSplitterFetch.nEndPos); gQ+_&'C  
} j|$y)FBX  
output.close(); BUy}Rn  
} .*wjkirF#~  
catch(IOException e){e.printStackTrace ();} jtVPv]  
catch(Exception e){e.printStackTrace ();} Z]>e& N  
} uwS'*5tU  
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//读取保存的下载信息（文件指针位置） !PP?2Ax  
private void read_nPos() Nm:|C 3_I  
{ $gD(MKR)~  
try{ ;Wrd=)Ka  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s)&R W#:X  
int nCount = input.readInt(); =ILo`Q~  
nStartPos = new long[nCount]; xzf)_ <  
nEndPos = new long[nCount]; T?}=k{C]  
for(int i=0;i<nStartPos.length;i++) |sZ9/G7  
{  q&Ua(I  
nStartPos = input.readLong(); J`D<  
nEndPos = input.readLong(); V:"\(Y  
} va*>q-QCr  
input.close(); cF<DUr)Ve  
} pcxl2I  
catch(IOException e){e.printStackTrace ();} ()IgSj?,  
catch(Exception e){e.printStackTrace ();} #
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} qP.VK?jF|  
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private void processErrorCode(int nErrorCode) s
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{ 0#[Nfe*  
System.err.println("Error Code : " + nErrorCode); LF,c-Cv!jL  
} ;7og  
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//停止文件下载 j~j V`>A  
public void siteStop() ne
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{ GH)+yD[o  
bStop = true; ~|d?o5W  
for(int i=0;i<nStartPos.length;i++) %KVRiX  
fileSplitterFetch.splitterStop(); 5>k~yaju/  
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} HBkQ`T  
} GISI8W^  
//负责部分文件的抓取 6 VJj(9%  
**FileSplitterFetch.java 21J82M  
*/ g='2~c  
package NetFox; Y?SJQhN6W  
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import java.io.*; E]Gq!fA&<  
import java.net.*; ;0}"2aGY  
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public class FileSplitterFetch extends Thread { eMMiSO!3  
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String sURL; //File URL nLLHggNAV  
long nStartPos; //File Snippet Start Position MhB=+S[@  
long nEndPos; //File Snippet End Position ?=o]Wx0(9  
int nThreadID; //Thread's ID HOI`F3#XI  
boolean bDownOver = false; //Downing is over ,3TD $2};.  
boolean bStop = false; //Stop identical kR|DzB7  
FileAccessI fileAccessI = null; //File Access interface 2F)OyE  
.\\#~r`t3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Jx[e{o)o  
{ )uJ`E8>-  
this.sURL = sURL; Z`h_oK#y15  
this.nStartPos = nStart; 20xGj?M  
this.nEndPos = nEnd; x-k/rZ  
nThreadID = id; F,$$N>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AyXKhj#Ml  
} NNV.x7  
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public void run() H0Xda.Y(  
{ pNme jz:  
while(nStartPos < nEndPos && !bStop) E$fy*enON  
{ R1%T>2"~&  
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try{ B ~bU7.Cd  
URL url = new URL(sURL); 3gXUfv2ID  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #3jZ7RqzQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); A)0m~+?{J  
String sProperty = "bytes="+nStartPos+"-"; 'n`$c{N<tM  
httpConnection.setRequestProperty("RANGE",sProperty); , Vr6  
Utility.log(sProperty); w0OK.fj  
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InputStream input = httpConnection.getInputStream(); T>?1+mruM  
//logResponseHead(httpConnection); Xq$0% WjG  
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byte[] b = new byte[1024]; q"vT]=Y}:  
int nRead; h v+i{Z9!]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 438>)=  
{ _e^V\O>  
nStartPos += fileAccessI.write(b,0,nRead); nsn,8a38  
//if(nThreadID == 1) g)Uh   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hRiGW_t  
} qt)mUq;>  
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m=y)i]=1  
Utility.log("Thread " + nThreadID + " is over!"); ?|F;x"  
bDownOver = true; 3Q6
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//nPos = fileAccessI.write (b,0,nRead); _dY}86{  
}  Hh/#pGf2  
catch(Exception e){e.printStackTrace ();} SQRz8,sqkw  
} +4RaN`I  
} <AXYqH7%A  
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//打印回应的头信息 <0MUn#7'  
public void logResponseHead(HttpURLConnection con) Kn]WXc|("  
{ hj[g2S%X  
for(int i=1;;i++) }e6:&`a xD  
{ 3@A k6Uh  
String header=con.getHeaderFieldKey(i); ucO]&'hu:  
if(header!=null) V)@scB|>,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4df1)<}U-  
Utility.log(header+" : "+con.getHeaderField(header)); [C#pMLp,~  
else =1uI >[aN  
break; Np)!23 "  
} {RO=4ba{J  
} &}?e:PEy  
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public void splitterStop() od|.E$B  
{ mcracj[B  
bStop = true; Q?q m~wD  
} m]vr|:{6/  
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} EZFWxR/  
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/* ]].21  
**FileAccess.java y->iv%
 
*//文件访问(定位，写) h Nw
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package NetFox; U3QnWPt}>  
import java.io.*; O*7~t17  
;RYKqUE  
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public class FileAccessI implements Serializable{ <WmCH+>?r  
)<&QcO_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K!mgh7Dx  
RandomAccessFile oSavedFile; ' ga2C\)  
long nPos; 5sUnEHN  
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public FileAccessI() throws IOException '%4,!  
{ Ks-><-2+N  
this("",0); _Fjv.VQ,  
} >aK&T"  
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public FileAccessI(String sName,long nPos) throws IOException AJ}Q,E  
{ "/=xu|  
oSavedFile = new RandomAccessFile(sName,"rw"); H9?~#GPb  
this.nPos = nPos; cR} =3|t  
oSavedFile.seek(nPos); ~+hG}7(:  
} wz=I+IN:  
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public synchronized int write(byte[] b,int nStart,int nLen) 5 Da(DA  
{ G_@H:4$3  
int n = -1; 04TV./uA  
try{ 9|,AhyhO  
oSavedFile.write(b,nStart,nLen); (@9-"W  
n = nLen; Z$@Nzza-  
} U# gmk0>t{  
catch(IOException e) Zuf&maa S  
{ 4a~_hkY]  
e.printStackTrace (); +{Ttv7l_2  
} ,q1RJiR  
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return n; }^t?v*kcA  
} 5q[@N J  
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} l0f6Lxfz  
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.*{LPfD|  
/* YDJc
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**SiteInfoBean.java !% Md9Mu!o  
*/ (nm&\b~j  
package NetFox; H^~!t{\  
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public class SiteInfoBean { ;nbvn  
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private String sSiteURL; //Site's URL OB:G5B`  
private String sFilePath; //Saved File's Path =:DNb(  
private String sFileName; //Saved File's Name IN"qJ3<k  
private int nSplitter; //Count of Splited Downloading File E*zk?G|  
+9t@eHJT1  
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public SiteInfoBean() ]v#Q\Q8>  
{//nSplitter的缺省值为5 uzOZxW[e  
//default value of nSplitter is 5 ul E\>5O4h  
this("","","",5); OLq/OO,w  
} H4U;~)i  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a"EXR-+8  
{ />$kDe  
sSiteURL= sURL; q-H]Hxv  
sFilePath = sPath; G|V ^C_:  
sFileName = sName; e>/PW&Z8Z  
this.nSplitter = nSpiltter; wp$=lU{B  
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} hM-qC|!  
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public String getSSiteURL() Mppb34y  
{
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return sSiteURL; SRMy#j-  
} B; ~T|exu  
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public void setSSiteURL(String value) D .E
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{ {"s8X(#_sC  
sSiteURL = value; 1cPi>?R:  
} kC)dia{$  
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public String getSFilePath() *ood3M[M^  
{ vg<_U&N=-r  
return sFilePath; qzq>C"z\Y$  
} u >x2  
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public void setSFilePath(String value) A\:M}D-(  
{ l#Iof)@#  
sFilePath = value; F$.M2*9  
} I3$v-OiL  
7l?-2I'c  
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public String getSFileName() nRvV+F0#  
{ +:D0tYk2B  
return sFileName; {oO!v}]  
} ^7=
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public void setSFileName(String value) O*CKyW_$t  
{ [qc90)^Q,  
sFileName = value; wEk9(|  
} /#blXI  
p< XjiRq  
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public int getNSplitter() .iw+#  
{ :[Fwc  
return nSplitter; )V3G~p=0  
} kIQMIL0+  
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public void setNSplitter(int nCount) t1xX B^.M{  
{ Fm:Ri$iT  
nSplitter = nCount; =*t)@bn  
} gq/q]Fm\  
} O -@7n0  
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8I JFQDGA9  
/* N'IzHyo.  
**Utility.java T<
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*/ J-=&B5"O>  
package NetFox; azN<]u@.  
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public class Utility { n{|~x":9V  
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public Utility() i9$ -lk  
{ B\BP:;"  
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} "H6DiPh.E  
a&9+<  
//线程睡眠 sOv:/'
 
public static void sleep(int nSecond) ZfoI7<?33  
{ @r=O~x  
try{ 64Q{YuI  
Thread.sleep(nSecond); rcAx3AK.  
} {o AJL  
catch(Exception e) o[aRG7C  
{ fE,\1LK4  
e.printStackTrace (); c.r]w  
} z" 4$mh  
} [WuN?H  
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//日志 y3kXfSe  
public static void log(String sMsg) 0rooL<~fa  
{ _>0I9.[5  
System.err.println(sMsg); KftZ^mk+p  
} uK1DC i  
.*i.Z   
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public static void log(int sMsg) (6!W8x7  
{ !np-Jmi  
System.err.println(sMsg); L~=h?C<  
} c#Y/?F2p  
} PIl:z?q({  
J.35Ad1hM  
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/* K8daSvc  
**TestMethod.java qJj"WU5  
*/ 6;Wns'  
package NetFox; b
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a/^ojn  
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public class TestMethod { wa2?%y_G  
!UDTNF?1  
:;HJ3V;  
public TestMethod() t,Ss3  
{ ///xx/weblogic60b2_win.exe `B-jwVrN(  
try{ oP!oU2eqK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =~15q=XY0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '9.L5*wh]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !W^P|:Qt  
fileFetch.start(); ~x4]^XS  
} 5LMAy"  
catch(Exception e){e.printStackTrace ();} f0S$p R  
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} )
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#?u#=]  
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public static void main(String[] args) Xw)W6H|  
{ C;>!SRCp  
new TestMethod(); Z4KYVHD,  
} =^3 Z L  
} z>}H[0[#  
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