http断点续传简单实现（java)

/* y,F|L?dIq  
**SiteFileFetch.java #I-qL/Lm  
*/ gk^`-`P  
package NetFox; 3d;w\#?L;  
import java.io.*; 1,Uf-i  
import java.net.*; C'&t@@
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public class SiteFileFetch extends Thread { XTKAy;'5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3FQ
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long[] nStartPos; //开始位置 N 6t`45  
long[] nEndPos; //结束位置 A4IPd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @~j--L  
long nFileLength; //文件长度 o%3VE8-  
boolean bFirst = true; //是否第一次取文件 j\%m6\{n|  
boolean bStop = false; //停止标志 rhH !-`m  
File tmpFile; //文件下载的临时信息 Sd?+j;/"  
DataOutputStream output; //输出到文件的输出流 cS;O
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +V,Ld&r  
public SiteFileFetch(SiteInfoBean bean) throws IOException Uv|^k8(  
{ E>L_$J-A-  
siteInfoBean = bean; pcO{%]?p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MngfXm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dx)v`.%V  
if(tmpFile.exists ()) 3F\UEpQ  
{ w@$_2t  
bFirst = false; 
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read_nPos(); &?0hj@kd~  
} wrEYbb  
else 2`cVi"U  
{ W't.e0L<6  
nStartPos = new long[bean.getNSplitter()]; &aWY{ ?_  
nEndPos = new long[bean.getNSplitter()]; IfF&QBi  
} &Tn7  
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} uTIl} N  
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public void run() InfUH8./t  
{ idGhWV'  
//获得文件长度 tbq_Rg7s  
//分割文件 >YP]IQ  
//实例FileSplitterFetch &k0c|q]  
//启动FileSplitterFetch线程 gt:Ot0\7  
//等待子线程返回 gLQbA$gB  
try{ P#x]3
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if(bFirst) *h Bo,   
{ d
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nFileLength = getFileSize(); L}.V`v{zc  
if(nFileLength == -1) 5:x .<  
{ #7dM %  
System.err.println("File Length is not known!"); BGZvgMxLJ  
} /u N3"m5i  
else if(nFileLength == -2) QAK.Qk?Qu  
{ RWK##VHK  
System.err.println("File is not access!");
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} f')3~)"  
else iT"H%{+~  
{ liG3   
for(int i=0;i<nStartPos.length;i++) x|IG'R1:Y  
{ Bg0 aLU)[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); & wG3RR|  
} jHWJpm(  
for(int i=0;i<nEndPos.length-1;i++) _<P~'IN+n  
{ aShZdeC*f  
nEndPos = nStartPos[i+1]; ^><B5A>;  
}
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nEndPos[nEndPos.length-1] = nFileLength; &m>txzo  
} ]Zz<9zix  
} (!&g (l;  
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//启动子线程 #$(wfb9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z0m[25FQG  
for(int i=0;i<nStartPos.length;i++) | QI-gw  
{ 2\1\Jn#q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4!r> ^a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q'p>__Ox  
nStartPos,nEndPos,i); dwt<s[k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4uUR2J  
fileSplitterFetch.start(); )B'U_*  
} #pz{,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m K@a7fF?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G$HLta  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sw@*N  
nEndPos = " + nFileLength); S.Fip_  
// fileSplitterFetch[nPos.length-1].start(); ]0wmvTR  
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//等待子线程结束 lt&30nf=  
//int count = 0; I NE,/a=  
//是否结束while循环 ~IE5j,SC  
boolean breakWhile = false; TAu*lL(F  
 YErn50L  
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while(!bStop) WsCzC_'j.  
{ ^2PQ75V@.  
write_nPos(); +6* .lRA  
Utility.sleep(500); AH(O"v`  
breakWhile = true; b!' bu  
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for(int i=0;i<nStartPos.length;i++) WxS=Aip'  
{ 7#R& OQ  
if(!fileSplitterFetch.bDownOver) S-:7P.#Q  
{ 7TQh'j  
breakWhile = false; S hM}w/4  
break; ;,h*s,i  
}  s!E-+Gw  
} =9;jVaEMJL  
if(breakWhile) 9h6
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break; Pk; 9\0k7  
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S  
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//count++; r_Rjjo  
//if(count>4) rS 4'@a  
// siteStop(); ka&-tGg  
} uXNf)?MpA  
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System.err.println("文件下载结束！"); */L;6_  
} NW9k.D%  
catch(Exception e){e.printStackTrace ();} [vaG{4m  
} ^IGTGY]s  
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//获得文件长度 Xklp6{VH9  
public long getFileSize() NwG&uc+Q  
{ [VPqI~u5)  
int nFileLength = -1; ytmlG%  
try{ ~^"cq S(  
URL url = new URL(siteInfoBean.getSSiteURL()); w I@ lO\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V_
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httpConnection.setRequestProperty("User-Agent","NetFox"); Iq\sf-1E  
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b['TRYc=:  
int responseCode=httpConnection.getResponseCode(); ):
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if(responseCode>=400) k- sbZL  
{ " I@Z:[=2  
processErrorCode(responseCode); V]PTAhc  
return -2; //-2 represent access is error $XI5fa4Tt  
} p
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String sHeader; @ec QVk  
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for(int i=1;;i++) /:e|B;P`k  
{ {F k]X#j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F,O+axO ja  
//Utility.log(in.readLine()); @Ds?  
sHeader=httpConnection.getHeaderFieldKey(i); +X;6%O;  
if(sHeader!=null) DI}h?Uf ,  
{ L#u6_`XJ+  
if(sHeader.equals("Content-Length")) RkLH}`#  
{ Q$,8yTM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >CPkL_@VZ=  
break; KX<RD|=  
} jVRd[  
} } 2)s%  
else D2!ww{t  
break; !4jS=Lhe>  
} fV}\  
} %e%nsj6  
catch(IOException e){e.printStackTrace ();} JZL!(>tI  
catch(Exception e){e.printStackTrace ();} @;<w"j`r  
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Utility.log(nFileLength); 1}8e@`G0.]  
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return nFileLength; V6$v@Zq  
} .<42-IEc  
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//保存下载信息（文件指针位置） X\%],"9%  
private void write_nPos() wOi>i`D&  
{ ydns_Z  
try{ #zy,x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _-8,}F}W#s  
output.writeInt(nStartPos.length); g'Xl>q  
for(int i=0;i<nStartPos.length;i++) c= a+7>  
{ T>uLqd{hH  
// output.writeLong(nPos); )cqhbR  
output.writeLong(fileSplitterFetch.nStartPos); )edM@beY_  
output.writeLong(fileSplitterFetch.nEndPos); }(tGjx]  
} yJp&A  
output.close(); 6!"15dPN  
} ZTmdS  
catch(IOException e){e.printStackTrace ();} Z@ws,f^e  
catch(Exception e){e.printStackTrace ();} v8%]^` '  
} e#'`
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//读取保存的下载信息（文件指针位置） u8<=FV3  
private void read_nPos() x:2[E-  
{ 9i`LOl:;  
try{ tIr66'8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3mJHk<m8T  
int nCount = input.readInt(); ]owH [wvX  
nStartPos = new long[nCount]; r>)\"U#  
nEndPos = new long[nCount]; >Le mTr  
for(int i=0;i<nStartPos.length;i++) Oy|9po  
{ e8lF$[i  
nStartPos = input.readLong(); Xj-3C[8@  
nEndPos = input.readLong(); \:=Phbn  
} &erNVD5o  
input.close(); 5;^8wh(  
} 9M7P]$^  
catch(IOException e){e.printStackTrace ();} ev?>Nq+Z  
catch(Exception e){e.printStackTrace ();} '[-/Xa['  
} ttw@nv% @  
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private void processErrorCode(int nErrorCode) #SqOJX~Q  
{ 9xKFX|*$  
System.err.println("Error Code : " + nErrorCode); XW#4C*5?d  
} Lw#hnLI.  
z H \*v'  
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//停止文件下载 Z?x]HB`r  
public void siteStop() {[9^@k  
{ ZbGyl}8ua  
bStop = true; isd[l-wAmf  
for(int i=0;i<nStartPos.length;i++) LTY.i3  
fileSplitterFetch.splitterStop(); R#ZDB]2  
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} wk/->Rz  
} ry< P LRN  
//负责部分文件的抓取 hW},%  
**FileSplitterFetch.java 7Ow7|  
*/ =0:hrg+Zgx  
package NetFox; ~xJD3Qf  
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import java.io.*; };+s0:H  
import java.net.*; zyR pHM$E  
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public class FileSplitterFetch extends Thread { zV&3l9?U  
9e=*jRs]l^  
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String sURL; //File URL =['ijD4TW  
long nStartPos; //File Snippet Start Position UiSc*_N"  
long nEndPos; //File Snippet End Position ~8X'p6  
int nThreadID; //Thread's ID kU Flp  
boolean bDownOver = false; //Downing is over ec0v
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boolean bStop = false; //Stop identical ZRHTvxf
 
FileAccessI fileAccessI = null; //File Access interface hB.dqv]^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7/1S5yUr|  
{ ?~K2&eo  
this.sURL = sURL; P:=ADW c  
this.nStartPos = nStart; fr?eOigbl  
this.nEndPos = nEnd; 'I~dJEW7  
nThreadID = id; %qQ(@TG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4mAtYm  
} %G@aZWk Sa  
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public void run() meL'toaJdQ  
{ "+WR[-n>\  
while(nStartPos < nEndPos && !bStop) /7#
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{ ^ UzF nW@a  
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try{ cm3Y!p{p"  
URL url = new URL(sURL); 'SieZI
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); st2>e1vg  
httpConnection.setRequestProperty("User-Agent","NetFox"); e&5K]W0{  
String sProperty = "bytes="+nStartPos+"-"; hJ<2bgQo  
httpConnection.setRequestProperty("RANGE",sProperty); @CmxH(-i-  
Utility.log(sProperty); {2x5 V#6  
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InputStream input = httpConnection.getInputStream(); qWFg~s#+  
//logResponseHead(httpConnection); (+_J0i t  
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byte[] b = new byte[1024]; GCKl[<9*  
int nRead; US|vYd}u+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0o]K6b  
{ >+#[O"  
nStartPos += fileAccessI.write(b,0,nRead); JW\"S  
//if(nThreadID == 1) "Pc,+>vh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =I(s7=Liu  
} hvyN8We  
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Utility.log("Thread " + nThreadID + " is over!"); b {5|2&=  
bDownOver = true; MUrY>FYgx  
//nPos = fileAccessI.write (b,0,nRead); 2z\F m/Z.  
} b{rmxtx  
catch(Exception e){e.printStackTrace ();} RtL<hD  
} L@Z &v'A  
} 4.'EEuRw\}  
+ LwoBn>6  
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//打印回应的头信息 /v{[Z&z  
public void logResponseHead(HttpURLConnection con) *eP4dGe&  
{ o zYI/b^  
for(int i=1;;i++) >{S$0D  
{ l.x }I"tf  
String header=con.getHeaderFieldKey(i); i[pf*W0g  
if(header!=null) /aqN`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); EVFfXv^  
Utility.log(header+" : "+con.getHeaderField(header)); (UZ*36@PJx  
else qt(:bEr^6b  
break; 8ilbX)O  
} IdxToMr  
} 4AYc8Z#'  
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public void splitterStop() v+#j>   
{ dYd~9  
bStop = true; WDdi}i>2  
} E/ZJ\@gzD  
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} }|Tg_+   
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/* (NdgF+'=  
**FileAccess.java !yX<v%>_0  
*//文件访问(定位，写) >U<nEnB$?  
package NetFox; yk<jlVF$j  
import java.io.*; N o(f0g.  
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public class FileAccessI implements Serializable{ nZCpT |M5  
]$*{<
  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1H=wl=K  
RandomAccessFile oSavedFile; Jche79B  
long nPos; o%%x'uC  
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public FileAccessI() throws IOException 0:'jU  
{ >iH).:j  
this("",0); Hi_Al,j:  
} RYl3txw  
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public FileAccessI(String sName,long nPos) throws IOException @>2rz  
{ V6MT>T  
oSavedFile = new RandomAccessFile(sName,"rw"); 93IOG{OAY  
this.nPos = nPos; 4AOS}@~W  
oSavedFile.seek(nPos); sBtG}Mo)  
} ~'J 
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public synchronized int write(byte[] b,int nStart,int nLen) )O@^H  
{ Gv,92ny!|  
int n = -1; i @9Qb  
try{ I"sobZ`  
oSavedFile.write(b,nStart,nLen); W}k?gg=  
n = nLen; P}9Y8$Y>U  
} &JhIn%=-  
catch(IOException e) p@8krOo`  
{ qM>OE8c#/  
e.printStackTrace (); {Okik}Oh  
} :Q ?J}N  
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return n; *{dD'9Bg  
} ZqbM%(=z(`  
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} h2|vB+W-  
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/* Z#Zzi5<  
**SiteInfoBean.java 4zqE?$HM'  
*/ Z"~6yF  
package NetFox; ,}IER  
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public class SiteInfoBean { 3TiXYH
 
7 Mki?EG  
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private String sSiteURL; //Site's URL "UoCT7X  
private String sFilePath; //Saved File's Path )fd-IYi-3  
private String sFileName; //Saved File's Name Rhv".epz  
private int nSplitter; //Count of Splited Downloading File j+13H
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public SiteInfoBean() VIz{}_~'s  
{//nSplitter的缺省值为5 y>7VxX0xi  
//default value of nSplitter is 5 <Xs@ \  
this("","","",5); F*4Qa  
} F
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <S8I"8{Mb  
{ *M5$ h*;v  
sSiteURL= sURL; 2>MP:yY;K  
sFilePath = sPath; Eo {1y  
sFileName = sName; QVSsi j  
this.nSplitter = nSpiltter; -wtTq ph'  
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} @8M'<tr<z  
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public String getSSiteURL() HV*:<2P%D  
{ vN0L(B  
return sSiteURL; a(x.{}uG,  
} }uvKE|umj  
&Qtp"#{  
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public void setSSiteURL(String value) b#Fk>j  
{ M=\d_O#;Z  
sSiteURL = value; (iCZz{l@~  
} Nn,vdu{^2  
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public String getSFilePath() ,WO%L~db  
{ t7*G91Hoq&  
return sFilePath; mq{$9@3  
} )WP]{ W)r  
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public void setSFilePath(String value) s=q%:uCO  
{ sxN>+v11z  
sFilePath = value; c?p0#3%L#  
} 4[5lX C  
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public String getSFileName() 9{9#AI.G  
{ }j5R@I6P  
return sFileName; /\,
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} Io,/ +#|  
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public void setSFileName(String value) H
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{ 33{;[/4  
sFileName = value; qXP1Q3  
} 7E!";HT  
[Q7->Wo|S:  
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public int getNSplitter() dr,B\.|jC  
{ D% v:PYf  
return nSplitter; _q$0lqq~u  
} %2@ Tj}xa  
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public void setNSplitter(int nCount) {UX"Epd);n  
{ 5bF9IH  
nSplitter = nCount; ]689Q%D  
} H7z>S G0  
} AQnJxIL:  
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/* a2cx  
**Utility.java c]s(u+i  
*/ c ,h.`~{  
package NetFox; eEWroF  
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public class Utility { ";-{~  
*/%$6s~  
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public Utility() V!pq,!C$v  
{ gD,YQ%aq  
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8  
V
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} RR[)UQ  
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//线程睡眠 P;)2*:--)  
public static void sleep(int nSecond) >~`Y
 
{ ]97Xu_  
try{ .iOw0z  
Thread.sleep(nSecond); LKK{j,g7  
} <_BqpZ^`  
catch(Exception e) SE-!|WR  
{ ^w;o

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e.printStackTrace (); 5}-)vsa`  
} `YFkY^T  
} yM(_P0  
#6*V7@9]3|  
//日志 ZfFIX5Qd\  
public static void log(String sMsg) tIi!*u  
{ U7nsMD  
System.err.println(sMsg); BpQ;w,sefq  
} pX>ua5Z  
7%:??*"~  
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public static void log(int sMsg) NDB*BmG  
{ bjM-Hd/K  
System.err.println(sMsg); K?h[.`}  
} (,- 5(fW  
} g2[K<  
L0X&03e=e:  
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/* F`YFo)W  
**TestMethod.java X0^zw^2W  
*/ X)FL[RO%q  
package NetFox; _N>wzkJ  
kN'|,eKH4  
w;N{>)hv  
public class TestMethod { LFEp  
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E0sbU<11  
public TestMethod() "_nX5J9  
{ ///xx/weblogic60b2_win.exe +G5'kYzJ  
try{ 4ggVj*{v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z{Hz;m:*_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $?H]S]#|}.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M?E9N{t8)a  
fileFetch.start(); _Ct}%-,4  
} H"Q(2I  
catch(Exception e){e.printStackTrace ();} 3mpP|b"  
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} qJ\X~5{  
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public static void main(String[] args) m
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{ 1zdYBb6;j  
new TestMethod(); \1=T sU&^  
} rER~P\-  
} f2uZK!:m  
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