http断点续传简单实现（java)

/* (
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**SiteFileFetch.java |\IN.W[EL  
*/ 
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package NetFox; n+q!l&&
 
import java.io.*; "x*egI  
import java.net.*; PV\+P6aIb  
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}Nm#q@o$P  
public class SiteFileFetch extends Thread { 0C irfcs}Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean S:oi<F  
long[] nStartPos; //开始位置 :AF =<X*5  
long[] nEndPos; //结束位置 ;=; 9tX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {rH@gz|@i  
long nFileLength; //文件长度 6GSI"M6s  
boolean bFirst = true; //是否第一次取文件 LzXmb 7A  
boolean bStop = false; //停止标志 %9N7Ln|%  
File tmpFile; //文件下载的临时信息 VE{3}S  
DataOutputStream output; //输出到文件的输出流 'o+L41  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Vjp1RWb  
public SiteFileFetch(SiteInfoBean bean) throws IOException %GA"GYL9'  
{ 33ef/MElD$  
siteInfoBean = bean; {kCw+eXn?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p~^D\jR.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'H&2HXw&2  
if(tmpFile.exists ()) XJ` ]ga  
{ Z/0fXn})  
bFirst = false; %gyLCTw  
read_nPos(); {/(D$"j(S  
} 7- ] as$  
else bg&zo;Ck8T  
{ ;/fF,L{c  
nStartPos = new long[bean.getNSplitter()]; sRx63{  
nEndPos = new long[bean.getNSplitter()]; y7 3VFb  
} %]DP#~7[|  
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} o+QE8H43  
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public void run() S=<}:#;u0  
{ 1#*a:F&re  
//获得文件长度 M/ni6%x  
//分割文件 Jz.NHiLct1  
//实例FileSplitterFetch v~V5`%  
//启动FileSplitterFetch线程 Vq5k+3W+  
//等待子线程返回 CBOi`bEf  
try{ L,`Lggq-  
if(bFirst) ;8*`{F[  
{ q
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nFileLength = getFileSize(); FsV'Cu@!U  
if(nFileLength == -1) WD2]&g  
{ pP?MWe Eg  
System.err.println("File Length is not known!"); KJ=6n%6  
} ^xHTWg%9  
else if(nFileLength == -2) v'qG26
  
{ Co9QW/'i  
System.err.println("File is not access!"); hMUs" <.  
} GCX G/k?w:  
else E4W -hq~  
{ 8a="/J  
for(int i=0;i<nStartPos.length;i++) XKttZOiGT  
{ i;jw\ed  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u7[ykyV  
} 9
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for(int i=0;i<nEndPos.length-1;i++) %Nhx;{  
{ ,TPISs  
nEndPos = nStartPos[i+1]; g[Ib,la_a  
} an
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nEndPos[nEndPos.length-1] = nFileLength; Xr2ou5zAn  
} /X(t1+  
} 8X`tU<A
b  
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//启动子线程 TUDr\' @/f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ? glSC$b  
for(int i=0;i<nStartPos.length;i++) IOoz^/'  
{ j!4et;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a1.Ptf eW|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _
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nStartPos,nEndPos,i); ]*FVz$>XM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vj\dA2!~  
fileSplitterFetch.start(); Ph}|dGb  
} %D8ZO0J7H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7L@K _ZJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M^iU;vo  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ryCI>vJz  
nEndPos = " + nFileLength); Y$Y_fjd_  
// fileSplitterFetch[nPos.length-1].start(); &)vC;$vD`  
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//等待子线程结束 ;SaX;!`39+  
//int count = 0; C;`XlQG `  
//是否结束while循环 {R61cD,n  
boolean breakWhile = false; ?jt}*q>X]  
+ 33@?fl.  
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while(!bStop) '|*?*
6q  
{ Yd=a}T  
write_nPos(); 8&~~j7p
,  
Utility.sleep(500);
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breakWhile = true; )m{Ye0!RD  
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for(int i=0;i<nStartPos.length;i++) S_v'hlrrT  
{ 9Xl5@%uz?z  
if(!fileSplitterFetch.bDownOver) &jczO-R^  
{ +|@rD/I6  
breakWhile = false; l)w Hl%p  
break; w'fT=v
)  
} DUe&r,(4O  
} E)7F\w  
if(breakWhile) S:q3QgU=X  
break; .G(llA}  
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//count++; MR,R}B$  
//if(count>4) I}t3 p|z  
// siteStop(); 0zCw>wBPW  
} r"a5(Q;n  
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System.err.println("文件下载结束！"); V$icWu  
} Vc%R$E%  
catch(Exception e){e.printStackTrace ();} qc!MG_{Y  
} #8bsxx!s  
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//获得文件长度
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public long getFileSize() bb`':3%  
{ aKlUX  
int nFileLength = -1; ;?~$h-9)  
try{ 1q3( @D5~+  
URL url = new URL(siteInfoBean.getSSiteURL()); R:AA,^Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *"98L+  
httpConnection.setRequestProperty("User-Agent","NetFox"); >,gvb5  
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int responseCode=httpConnection.getResponseCode(); ym/fFm6h  
if(responseCode>=400) Q
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{ %#Z/2<_  
processErrorCode(responseCode); TO*BH^5R  
return -2; //-2 represent access is error ^o@,3__7Q  
} Y<b-9ai<w  
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String sHeader; 2Nm>5l  
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1s*.A6EP"  
for(int i=1;;i++) je4w=]JV  
{ tpEI(9>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5P+t^\  
//Utility.log(in.readLine()); ]cC[-F[  
sHeader=httpConnection.getHeaderFieldKey(i); R@yyur~'_(  
if(sHeader!=null) TtDg*kZ  
{ 1w0OKaF5  
if(sHeader.equals("Content-Length")) )wtaKF.-  
{ ;.Ie#Vr1N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -MugnB6  
break; u=NSsTP&  
} 0\~Z5k`IT  
} %|l8f>3[  
else w[-Fm+A>  
break; e{9jn>\,a  
} j! NO|&k  
} -/dEsgO  
catch(IOException e){e.printStackTrace ();} C4#rA.nF|  
catch(Exception e){e.printStackTrace ();} oM1 6C|  
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Utility.log(nFileLength); lhYn5d)DV  
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return nFileLength; Y'3}G<'%  
} asgF1?r  
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//保存下载信息（文件指针位置） O:/yAc`  
private void write_nPos() 0l#)fJo  
{ qxJQPz  
try{ 9H]Lpi^OH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b2&V  
output.writeInt(nStartPos.length); h2;z4  
for(int i=0;i<nStartPos.length;i++) +~U=C9[gj  
{ uH^PQ  
// output.writeLong(nPos); ZRUhAp'<qj  
output.writeLong(fileSplitterFetch.nStartPos); ?Jusl8Sm  
output.writeLong(fileSplitterFetch.nEndPos); wVA|!>v  
} Hj1 EGCA  
output.close(); tAFti+Qb  
} -(JUd4#  
catch(IOException e){e.printStackTrace ();} {,j6\Cj4  
catch(Exception e){e.printStackTrace ();} Bl1Z4` 3  
} rn:!dV[  
|"$uRV=qm  
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//读取保存的下载信息（文件指针位置） ?vGffMm  
private void read_nPos() do>
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{ ?68uS;  
try{ :Ze+%d=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QldzQ%4c\  
int nCount = input.readInt(); d(*fy}  
nStartPos = new long[nCount]; I#FF*@oeM  
nEndPos = new long[nCount]; td-3h,\\  
for(int i=0;i<nStartPos.length;i++) n1:v HBM@\  
{ -,":5V26  
nStartPos = input.readLong(); ]y)Q!J )Q  
nEndPos = input.readLong(); baoD(0d  
} ]`w}+B'/  
input.close(); dd7 =)XT+  
} 2#/p|$;Ec'  
catch(IOException e){e.printStackTrace ();} qJT0Y/l:(  
catch(Exception e){e.printStackTrace ();} YY4-bNj[p  
} b}zBn8l  
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private void processErrorCode(int nErrorCode) >^"BEG9i:  
{ M`,XyIn  
System.err.println("Error Code : " + nErrorCode); "!Rw)=7O  
} IdRdW{o  
^!;=6}YR  
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//停止文件下载 [H"#7t.V-~  
public void siteStop() )Z@-DA*Q-  
{ g>7Y~_}  
bStop = true; {lzG*4?  
for(int i=0;i<nStartPos.length;i++) jV7&Y.$zF]  
fileSplitterFetch.splitterStop(); >n7["7HHk  
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} +ydm,aKk  
} WA.\*Nqze  
//负责部分文件的抓取 4W\,y_Qo  
**FileSplitterFetch.java ]B
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*/ T"E(  F  
package NetFox; 02]xJo  
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import java.io.*; 2N6=8Xy5K  
import java.net.*; /'>;JF  
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public class FileSplitterFetch extends Thread { X#+`e+Df  
? Ekq6uz\)  
1
}`LTPW9  
String sURL; //File URL RyRqH:p)3  
long nStartPos; //File Snippet Start Position cvAtwQ'  
long nEndPos; //File Snippet End Position }w!ps{*  
int nThreadID; //Thread's ID ":d*dl  
boolean bDownOver = false; //Downing is over j/<??v4F4  
boolean bStop = false; //Stop identical uJ'9R`E ]1  
FileAccessI fileAccessI = null; //File Access interface A1,4kqmE  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +>3]%i-\  
{ ?'~;Q)  
this.sURL = sURL; 1]/N2&  
this.nStartPos = nStart; oG_~3Kt  
this.nEndPos = nEnd; ~B@}R  
nThreadID = id; :+kUkb-/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o*7yax  
} S[@6Lp3q_  
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public void run() -Q`Cq|s  
{ 'rV2Bt,  
while(nStartPos < nEndPos && !bStop) "zZ&n3=@  
{ C"T,MH  
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try{ =O^7TrM  
URL url = new URL(sURL); cy:;)E>/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8 G?b.NE^  
httpConnection.setRequestProperty("User-Agent","NetFox"); eECj_eH-  
String sProperty = "bytes="+nStartPos+"-"; @]3*B%t  
httpConnection.setRequestProperty("RANGE",sProperty); I>m;G `  
Utility.log(sProperty); PbUI!Xqe`  
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InputStream input = httpConnection.getInputStream(); c57bf  
//logResponseHead(httpConnection); nJ# XVlHc  
>7FSH"8[,  
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byte[] b = new byte[1024]; *#ompm  
int nRead; ucFw,sB1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f sX;Nj]  
{ 0e9A+&r  
nStartPos += fileAccessI.write(b,0,nRead); x\;GoGsez  
//if(nThreadID == 1) 3Bd4 C]E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dt.-C_MO  
} Nzc>)2% N  
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Utility.log("Thread " + nThreadID + " is over!"); jg^^\n  
bDownOver = true; mSj76'L#  
//nPos = fileAccessI.write (b,0,nRead); u-/3(dKt  
} J:W'cH$cR  
catch(Exception e){e.printStackTrace ();} S^g]:Xh&  
} Fr/QW7B5  
} `1p?*9Ssn  
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//打印回应的头信息 ?hSha)1:  
public void logResponseHead(HttpURLConnection con) WA$ p_% r=  
{ & ^!v*=z  
for(int i=1;;i++) 4O Zy&,  
{ &x/k^p=  
String header=con.getHeaderFieldKey(i); Y=WR6!{  
if(header!=null) g
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); #y`k$20"  
Utility.log(header+" : "+con.getHeaderField(header)); AuM:2N2  
else L(Rorf~V  
break; ~g96o81V  
} E#~2wqK  
} Gm*Uv6?H?  
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public void splitterStop() [b pwg&Oo  
{ pgfu+K7?w  
bStop = true; "]9_Fv  
} D99N#36PU  
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} H!^C
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u> In(7\  
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/* 4}PeP^pj  
**FileAccess.java K+t];(  
*//文件访问(定位，写) 0wYiu  
package NetFox; :EaiM J_=  
import java.io.*; {C, #rj  
^8U6"O6|X  
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public class FileAccessI implements Serializable{ Cg?I'1]o6  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /T4VJ{D  
RandomAccessFile oSavedFile; }W)Mwu'W  
long nPos; _/8y1)I  
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public FileAccessI() throws IOException j!"iYtgV  
{ \j/}rzo]  
this("",0); )uuwwz  
} xP{m9_Qj  
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,$SkaTBe  
public FileAccessI(String sName,long nPos) throws IOException <y'qo8oqF  
{ } pSt@3o,  
oSavedFile = new RandomAccessFile(sName,"rw"); |4LQ\'N&  
this.nPos = nPos; 012:BZR  
oSavedFile.seek(nPos); paUyS1i  
} O\:;q*]
 
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public synchronized int write(byte[] b,int nStart,int nLen) ge@reGfsB1  
{ 'II vub#q  
int n = -1; ^$ZI>L0+  
try{ P|yGx)'^P  
oSavedFile.write(b,nStart,nLen); Z@8MhJ  
n = nLen; Ty(yh(oYF`  
} HK=CP0H  
catch(IOException e) U5-zB)V  
{ ]VmzKA|h+  
e.printStackTrace (); @ICejB<  
} =k_XKxd  
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return n; >zN" z)  
} 6qY\7R2+  
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} [Ja(ArO3|[  
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/* | 3hT{  
**SiteInfoBean.java $a)JCErN  
*/ kwDjK"  
package NetFox; 1NB2y[  
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$ $W{HsX  
public class SiteInfoBean { ZA) SJWwD  
,7WK<0  
R*zBnHAb!  
private String sSiteURL; //Site's URL @|jKO5Y  
private String sFilePath; //Saved File's Path cS. 7\0$  
private String sFileName; //Saved File's Name ^M[-K`c}  
private int nSplitter; //Count of Splited Downloading File Mt]=v}z  
_m)gO/02A  
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public SiteInfoBean() :9v*,*@x  
{//nSplitter的缺省值为5 )ylv(qgV  
//default value of nSplitter is 5 r|u6OF>  
this("","","",5); A} x_zt  
} |8&\
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1 P(&GYc  
{ Ew)n~!s  
sSiteURL= sURL; &/z
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sFilePath = sPath; 401/33yBJ  
sFileName = sName; 60.[t9pk6  
this.nSplitter = nSpiltter; d;*OO xQV  
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|*/uN~[  
} w%%6[<3%  
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`!5tH?bX  
public String getSSiteURL() $cp16  
{ UeutFNp  
return sSiteURL; @1`W<WP  
} *FI5z[8,  
/ynKKJx<Y  
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public void setSSiteURL(String value) &Sa_%:*D(  
{ \.XT:B_  
sSiteURL = value; tk]_QX %  
} Lqz}&A   
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public String getSFilePath() uM}dZp 1  
{ J,(U<%n  
return sFilePath; u(TgWp5WF  
} 0
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w
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public void setSFilePath(String value) p4<M|1Z&  
{ n9mM5H47  
sFilePath = value; 2<\yky  
} Ah8^^h|TPJ  
P?yOLG+)l)  
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public String getSFileName() ` maN5)  
{ Y3sNr)qss  
return sFileName; etQx
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} )f:!#v(K  
X=*Yzz}  
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public void setSFileName(String value) OoU'86)  
{ OLd$oxKR  
sFileName = value;  8E.5k@  
} h!X'SGK  
7#~m:K@  
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public int getNSplitter() Np5/lPb1  
{ =%#$HQ=  
return nSplitter; b>>=d)R  
} A{u\8-u  
?*MV ^IY  

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public void setNSplitter(int nCount) "\R@lUx.Y  
{ ]w&?k:y>  
nSplitter = nCount; tSh}0N)  
} dmTW]P2  
} G74a9li@  
]'bQ(<^#  
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/* ,sRrV $,"  
**Utility.java O. .@<.  
*/ ~[ ks|  
package NetFox; Cs~\FI1wR  
=^%Pwkz  
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public class Utility { S:B-nI  
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public Utility() VgC9'"|  
{ ;29XvhS8  
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$M8>SLd  
} -
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j8ohzX[Y  
//线程睡眠 +%cr?g  
public static void sleep(int nSecond) 8d*<Aki?;  
{ KWuj_.;  
try{ *M\i4FO8  
Thread.sleep(nSecond); 88+\mX;A#  
} 4-
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catch(Exception e) ;^H+ |&$>  
{ QWQ6j#`  
e.printStackTrace (); X0r#,u  
} Stp*JU  
} { P\8g8  
>i#_)th"U!  
//日志 9rvxp;  
public static void log(String sMsg) KohQ6q  
{ 5yN8%_)T  
System.err.println(sMsg); bZ@53  
} Xy(SzJ%  
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p  
pmpn^ZR  
public static void log(int sMsg) sR0e&Y  
{ qKb-aP-  
System.err.println(sMsg); /j5- "<;.  
} uZ39Vx  
} Y_ ;i  
x#}eC'Q  
576-X_a,  
/* AB|VO4-?  
**TestMethod.java p(b1I+!  
*/ (A<sFw?  
package NetFox; 0tm "kzy  
2KNKdV3NK  
HBf8!\0|/  
public class TestMethod { @ 6VH%  
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i:N^:%  
public TestMethod() :\= NH0M  
{ ///xx/weblogic60b2_win.exe QIz N
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try{ g(}8n bTA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~[/c'3+4qn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =K<I)2   
SiteFileFetch fileFetch = new SiteFileFetch(bean); W/F
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fileFetch.start(); +Gwe%p Q  
} CCvBE, ux  
catch(Exception e){e.printStackTrace ();} 2BU)qv-  
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} e.Q K%  
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public static void main(String[] args) Ch&]<#E>`  
{ XTXo xZ#w  
new TestMethod(); 3ijI2Zy  
} `h{mj|~  
} bqwW9D(  
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