http断点续传简单实现（java)

/* #$L/pRC  
**SiteFileFetch.java !'IZr{Y>  
*/ 'HCRi Z<  
package NetFox; ;l<Hen*  
import java.io.*; 49O_A[(d  
import java.net.*; =<)/lz] H  
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public class SiteFileFetch extends Thread { ' V*}d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean DMs8B&Y=  
long[] nStartPos; //开始位置 9C{Xpu  
long[] nEndPos; //结束位置 l@u  "iGw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6W3."};  
long nFileLength; //文件长度 +lZ-xU1  
boolean bFirst = true; //是否第一次取文件 Eza^Tbq%j?  
boolean bStop = false; //停止标志 AE`UnlUSF  
File tmpFile; //文件下载的临时信息 n "^rS}Y]  
DataOutputStream output; //输出到文件的输出流 1vCp<D9<  
w@O)b-b|w  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;`kOFg#`)c  
public SiteFileFetch(SiteInfoBean bean) throws IOException S4_ZG>\VT  
{ fCnwDT  
siteInfoBean = bean; zV;NRf) 9.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p]?eIovi  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zf5%|7o  
if(tmpFile.exists ()) ZCb@!V}=  
{ W<[7LdAB  
bFirst = false;  j0O1??  
read_nPos(); /L2n ~/  
} -]Mk} z$  
else GukwN]*OY  
{ 4ji'6JHPg  
nStartPos = new long[bean.getNSplitter()]; xaV3N[Zd  
nEndPos = new long[bean.getNSplitter()]; +l!.<:sp  
} ,zH\P+*  
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} :D>flZi  
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public void run() uH7rt  
{ 1DL+=-  
//获得文件长度 J p%J02  
//分割文件 UYQ@ub  
//实例FileSplitterFetch /k^j'MMQs6  
//启动FileSplitterFetch线程 I\rjw$V#  
//等待子线程返回 N"Y%*BkH  
try{ 6& hiW]Adm  
if(bFirst) ?duw0SZ  
{
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nFileLength = getFileSize(); Vhb~kI!x  
if(nFileLength == -1) F8{T/YhZ  
{ 66+]D4(k  
System.err.println("File Length is not known!"); 8JW0;H<  
} J4iu8_eH!D  
else if(nFileLength == -2) '-G,7!.,r%  
{ `Pwf?_2n-  
System.err.println("File is not access!"); 2)n%rvCQ  
} XuZgyt"=r  
else 0tMzVxS  
{ V/R@=[  
for(int i=0;i<nStartPos.length;i++) ,'l.u?SKyd  
{ 2"P1I
  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qEdY]t   
} vt5>>rl  
for(int i=0;i<nEndPos.length-1;i++) !y!s/i&P%  
{ I<xcVY9L  
nEndPos = nStartPos[i+1]; 6O 2sa-{d  
} 6Q+VW_~  
nEndPos[nEndPos.length-1] = nFileLength;  60f%J1u  
} eU-A_5  
} FgPmQ  
b+Vlq7Bc  
p!?7;  
//启动子线程 r.:f.AY{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q?L*Luu+  
for(int i=0;i<nStartPos.length;i++) ,pkzNe`F  
{ `fVzY"Qv k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qPhVc9D#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AO5a  
nStartPos,nEndPos,i); p{SIGpbR&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Esg:  
fileSplitterFetch.start(); T).}~i;!  
} {c&9}u$e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P5"B7>L:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #}Ays#wA>?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OU mZ|  
nEndPos = " + nFileLength); 0{?%"t\/f  
// fileSplitterFetch[nPos.length-1].start(); +OB&PE  
[!ZYtp?Hf  
}2Im?Q  
//等待子线程结束 8-K4*(-dL
 
//int count = 0; >Wpdq(o  
//是否结束while循环 X&K,,C  
boolean breakWhile = false; +ZBj_Vw*|  
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~ r$I&8  
while(!bStop) _qQo}|/q  
{ % %2~%FVb  
write_nPos(); !yV)EJ:$  
Utility.sleep(500); d{C8}U  
breakWhile = true; U
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for(int i=0;i<nStartPos.length;i++) \D[~54  
{ sn@)L~$V  
if(!fileSplitterFetch.bDownOver) I&x69  
{ Ww{-(Ktx  
breakWhile = false; #e9XU:9@g  
break; ]7h;MR  
} xz,M>Ua  
} vha@YPC=  
if(breakWhile) 0upZ4eN  
break; ,-Lv3  
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//count++; Uf$IH!5;Z  
//if(count>4) z_z'3d.r7  
// siteStop(); a1weTn*  
} Yc(lY N  
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System.err.println("文件下载结束！"); Aca?C  
} |C t Q  
catch(Exception e){e.printStackTrace ();} ):Ekf2  
} `k08M)  
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//获得文件长度 r1$x}I#Zv  
public long getFileSize()
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{ "n<u(m8E  
int nFileLength = -1; x1:1Jj:  
try{ +OUM 4y  
URL url = new URL(siteInfoBean.getSSiteURL()); Zo,]Dx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a+\s0Qo<  
httpConnection.setRequestProperty("User-Agent","NetFox"); l02aXxT)]  
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int responseCode=httpConnection.getResponseCode(); 9893{}\cB  
if(responseCode>=400) +T7FG_  
{ .>(qZEF  
processErrorCode(responseCode); E95VR?nUg  
return -2; //-2 represent access is error ?Ye%k  
} WF<*rl  
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String sHeader; j!`2Z@  
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for(int i=1;;i++) u\UI6/  
{ cuQ=bRIb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z.kBQ{P  
//Utility.log(in.readLine()); 2wgdrO|B  
sHeader=httpConnection.getHeaderFieldKey(i); {|@N~c+  
if(sHeader!=null) >[g'i+{  
{ 7jF2m'(  
if(sHeader.equals("Content-Length")) t]pJt  
{ :SpPT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !myF_cv}'  
break; fP1fm  
} mDU-;3OqF  
} 9M-/{D^+<  
else %!)Dk<  
break; ,u>K##X\  
} 3bB%@^<  
} gH/k}M7tA#  
catch(IOException e){e.printStackTrace ();} ;4]l P  
catch(Exception e){e.printStackTrace ();} ^KFwO=I@PV  
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Utility.log(nFileLength); ,1e@Y~eZ  
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return nFileLength; N&lKo}hk  
} I~Zm**L  
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//保存下载信息（文件指针位置）  '+C%]p  
private void write_nPos() Jz\'%O'  
{ YcBAW4B`  
try{ rx;zd?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); k$} 6Qd  
output.writeInt(nStartPos.length); ZsYT&P2  
for(int i=0;i<nStartPos.length;i++) x68s$H  
{ [p_C?hHO  
// output.writeLong(nPos); =p';y&  
output.writeLong(fileSplitterFetch.nStartPos); pG:)u cj  
output.writeLong(fileSplitterFetch.nEndPos); u@zBE? g  
} -^7n+ QX  
output.close(); D$c4's`5  
} LHP?!rO0  
catch(IOException e){e.printStackTrace ();} $rE_rZ+]="  
catch(Exception e){e.printStackTrace ();} l,3[hx  
} \Tj(]  
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//读取保存的下载信息（文件指针位置） PK* $  
private void read_nPos() b%,`;hy{  
{ sWnU*Q  
try{ n-_-
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^KMZB  
int nCount = input.readInt(); [t`QV2um  
nStartPos = new long[nCount]; _/!IjB:(70  
nEndPos = new long[nCount]; 3^zOG2  
for(int i=0;i<nStartPos.length;i++) Fc<+N0M{  
{ hYNb9^  
nStartPos = input.readLong(); BK]q^.7+:  
nEndPos = input.readLong(); Gwkp(
9d  
} vd<" G}  
input.close(); Ws`P(WHm  
} SLc'1{  
catch(IOException e){e.printStackTrace ();} WChJ <[]W  
catch(Exception e){e.printStackTrace ();} D*j\g
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} `p%&c%*A  
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private void processErrorCode(int nErrorCode) `W8dayZt  
{ ABp/uJI
)  
System.err.println("Error Code : " + nErrorCode); 5<ycF_  
} Kq';[Yc  
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//停止文件下载 YvK8;<k@-?  
public void siteStop() ?79ABm a  
{ )y:~T\g  
bStop = true; VscEd
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for(int i=0;i<nStartPos.length;i++) fW4N+2  
fileSplitterFetch.splitterStop(); R@r"a&{/  
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} U.G**v  
} ;[@< ,  
//负责部分文件的抓取 &a p{|>3  
**FileSplitterFetch.java ;HJ|)PN5L  
*/ g+k0Fw]!  
package NetFox; 3B|o   
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import java.io.*; .~6p/fHX  
import java.net.*; D[)g-_3f6<  
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public class FileSplitterFetch extends Thread { o84!$2P+w  
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String sURL; //File URL NQ!jkojD  
long nStartPos; //File Snippet Start Position n
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long nEndPos; //File Snippet End Position ;%AK< RT  
int nThreadID; //Thread's ID 7!`,P  
boolean bDownOver = false; //Downing is over snV,rZ  
boolean bStop = false; //Stop identical s7<x~v+^  
FileAccessI fileAccessI = null; //File Access interface N$H0o+9-Y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 969*mcq'  
{ :'!,L0I|t  
this.sURL = sURL; PK5xnT:  
this.nStartPos = nStart; $aX}i4F  
this.nEndPos = nEnd; BXVmt!S5F  
nThreadID = id; Sf)VQ5U!Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;z>)&F  
} hX]vZR&R  
(<pc4#B@*  
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public void run() QOkPliX  
{ l=ZhHON  
while(nStartPos < nEndPos && !bStop) Dm[4`p@IY\  
{ jYRwtP\  
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!t6:uC7H  
try{ t+5JIQY>  
URL url = new URL(sURL); RJ1Q.o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e@6<mir[4  
httpConnection.setRequestProperty("User-Agent","NetFox"); Qj?FUxw  
String sProperty = "bytes="+nStartPos+"-"; d:6?miMH]t  
httpConnection.setRequestProperty("RANGE",sProperty); g#;w)-Zj  
Utility.log(sProperty); o64&BpCK  
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InputStream input = httpConnection.getInputStream(); h\b]>q@  
//logResponseHead(httpConnection); B]q &?~  
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byte[] b = new byte[1024]; `
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int nRead; ,K8O<Mw8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GH![rK  
{ {b[8x   
nStartPos += fileAccessI.write(b,0,nRead); 'QjX2ytgX  
//if(nThreadID == 1) 7^h?<X\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *Y6BPFE*4  
} O/>$kG%ge  
6';'pHqe  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; 2Tt@2h_L  
//nPos = fileAccessI.write (b,0,nRead); Bhl
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} o-B9r+N  
catch(Exception e){e.printStackTrace ();} IDb|J%e^P  
} JG
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} &+=A;Y)  
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//打印回应的头信息 Hm4:m$=p4  
public void logResponseHead(HttpURLConnection con) +s c|PB  
{ J.mEOo!>  
for(int i=1;;i++) &""~Pn
8  
{ K.n #;|  
String header=con.getHeaderFieldKey(i);
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if(header!=null) 7M<Ae D%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <XX\4[wb  
Utility.log(header+" : "+con.getHeaderField(header)); Sb+pB58&N  
else <*~vZT i(  
break; Qi#%&Jz>f  
} Z16G  
} R 28v5  
s!``OyI/Z  
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public void splitterStop() |_8-3  
{ ,2/qQD n/  
bStop = true; a1B_w#?8  
} I2(5]85&]s  
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} 1Dg\\aUk  
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/* f@+[
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**FileAccess.java G*ZHLLO4S\  
*//文件访问(定位，写)
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package NetFox; c%
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import java.io.*; }kdYR#{s  
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public class FileAccessI implements Serializable{ Gvw4ot/  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ey=
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RandomAccessFile oSavedFile; M2_sxibI  
long nPos; .a1WwI  
]
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[ /w{,+U  
public FileAccessI() throws IOException 8Br*  
{  ;?1H&  
this("",0); UP}Ys*  
} W)ihk\E  
sH(4.36+  
8i=J(5=  
public FileAccessI(String sName,long nPos) throws IOException 2ixg ix  
{ : I28Zi*  
oSavedFile = new RandomAccessFile(sName,"rw"); ilEWxr;,  
this.nPos = nPos; s\,F6c  
oSavedFile.seek(nPos); qP6]}Aj]  
} :TqvL'9o  
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{$)zC*l  
public synchronized int write(byte[] b,int nStart,int nLen) r5> FU>7'  
{ oE[wOq+  
int n = -1; j<>E Fd  
try{ k`U")lv  
oSavedFile.write(b,nStart,nLen); xGCW-YR9  
n = nLen; 3~}G~ t  
} 
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catch(IOException e) hC
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{ $As;Tvw.  
e.printStackTrace (); `@q
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} u~7m
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return n; |} ;&xI  
} X:bv ?o>Y  
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} 2%i_SX[  
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/* G?CaCleG  
**SiteInfoBean.java q,3_)ZOq  
*/ A94ZG:  
package NetFox; '=K [3%U  
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public class SiteInfoBean { Md(AqaA  
AM  cHR=/  
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private String sSiteURL; //Site's URL t+7h(?8L  
private String sFilePath; //Saved File's Path @^]wT_r  
private String sFileName; //Saved File's Name `&2~\o/  
private int nSplitter; //Count of Splited Downloading File bD*V$w*P  
{I0b%>r=  
+?Vj}p;  
public SiteInfoBean() g*?)o!_*  
{//nSplitter的缺省值为5 S7]\tw_L)  
//default value of nSplitter is 5 )zz^RB\p  
this("","","",5); H6%QM}t  
} (? j $n?p  
8}z]B^?Fy  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (T:OZmEO.  
{ jA_wOR7$  
sSiteURL= sURL; oU`8\n](  
sFilePath = sPath; <"
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sFileName = sName; ?3 {&"  
this.nSplitter = nSpiltter; DKw%z8ft|  
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} V}gP'f07zy  
q)vdDdRe_  
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public String getSSiteURL() A/V"&H[  
{ %;ZWYj`]n  
return sSiteURL; ^f*}]`S  
} h!.#r*vV  
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:j_OO5b!  
public void setSSiteURL(String value) &N4Jpa}w/%  
{ zY_xJ"/9  
sSiteURL = value; W <.h@Rz+  
} bW03m_<M<1  
,{DZvif   
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public String getSFilePath() ms9zp?M  
{ wM
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return sFilePath; -7jP'l=h  
} &D@/_m $  
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public void setSFilePath(String value) MO}J  
{ v`&  
sFilePath = value; qZw4"&,j$  
} u\LG_/UJV1  
:sO^b*e /  
&q~**^;'  
public String getSFileName() }#0MJ6L  
{ Ip c2Qsa  
return sFileName;
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} nADt8  
~q0g7?}&  
!;Hi9,<#7g  
public void setSFileName(String value) &"X6s%ZH|  
{ fzcPi9+  
sFileName = value; r*$$82s  
} V.<$c1#=$  
>JdA,i}1  
X^204K%:  
public int getNSplitter() C-25\  
{ "mT95x\NA\  
return nSplitter; "s[Y$!#  
} ! C}t)R]^  
^Ej4^d  
]LGp3)T-  
public void setNSplitter(int nCount) lIR0jgP@z  
{ Hgu:*iYA  
nSplitter = nCount; nT7{`aaQl  
} Y)D~@|D,  
} `v2]Jk<  
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#bRr|`  
/* ;VQFz&Q$u  
**Utility.java \Xy]z  
*/ CR*9-Y93  
package NetFox; O[nl#$w  
kk`BwRh)d;  
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public class Utility { /cmnX'z  
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public Utility() dU!`aPL?  
{ 3,`.$   
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} sU7>q}!  
>;E[XG^  
//线程睡眠 TF\<`}akX  
public static void sleep(int nSecond) sOyWsXd+R'  
{ 5fh@nR  
try{ Z=;+) #,  
Thread.sleep(nSecond); ZqI.n4:9  
} x.>E7 +  
catch(Exception e) @ mzf(Aq  
{ .3;bUJ1  
e.printStackTrace (); @G/':N   
} kBPFk t2  
} m7:E73:  
'WqSHb7  
//日志 %}z/_QZ  
public static void log(String sMsg) %9_wDfw~  
{ jgiP2k[Xom  
System.err.println(sMsg); v\9:G  
} ETu7G5?  
!U02>X   

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public static void log(int sMsg) Kd_WN;l  
{ )G(6=l*  
System.err.println(sMsg); )g4oUZDF  
} JOj\#!\>k0  
} X,- ' v[z  
Z=: oIAe  
JCIm*6~  
/* !g? ~<`  
**TestMethod.java -Q@jL{Ue  
*/ ] =Js5  
package NetFox; //--r5Q  
;qI5GQ {  
l+'1>T.I  
public class TestMethod { #vO3*-hs  
o3H+.u
$  
1SBc:!2  
public TestMethod() qa![oMKc  
{ ///xx/weblogic60b2_win.exe )k&pp^q\  
try{ ujcS>XN,1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `92 D]^g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ArkFC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i'!M<>7  
fileFetch.start(); .?SClTqg  
} >l$vu-k)~4  
catch(Exception e){e.printStackTrace ();} ~L(_q]  
bw*
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} YQR*?/?a  
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public static void main(String[] args) SwQ.tK1p  
{ }iy`Ko+B"b  
new TestMethod(); $ql-"BB  
} _ED1".&#f  
} :,F^{  
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