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http断点续传简单实现(java)

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/* !\BZ_guz  
**SiteFileFetch.java ml1%C%  
*/ ?-mOAHW0q  
package NetFox; L98T!5)  
import java.io.*; 7G-?^  
import java.net.*; 3s%ND7!/  
6Nn+7z<*&z  
7(.Z8AO  
public class SiteFileFetch extends Thread { M;ADL|  
s[0`  
q: FhuOP  
SiteInfoBean siteInfoBean = null; //文件信息Bean OmBz'sp:  
long[] nStartPos; //开始位置 HV/:OCK  
long[] nEndPos; //结束位置 b6f OHy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |R@T`dW  
long nFileLength; //文件长度 ,7)hrA$(  
boolean bFirst = true; //是否第一次取文件 a6DR' BC  
boolean bStop = false; //停止标志 yFDeY PZP  
File tmpFile; //文件下载的临时信息 [I4M K%YQ  
DataOutputStream output; //输出到文件的输出流 YFB>GQ;  
lN g){3  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Jk\-e`eE  
public SiteFileFetch(SiteInfoBean bean) throws IOException j;coPehB  
{ lRg?||1ik  
siteInfoBean = bean; r@zT!.sc!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); S5TVfV5LI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 04|ZwX$>+  
if(tmpFile.exists ()) vQi=13Pw  
{ _`\!+qGq  
bFirst = false; [q[37;ZEQ  
read_nPos(); ?c RF;!o"  
} 0!dNW,NfJ  
else ye$_=KARP  
{ [%dsq`b#  
nStartPos = new long[bean.getNSplitter()]; m- <y|3  
nEndPos = new long[bean.getNSplitter()]; wX]$xZ!s  
} *%KIq/V  
{ac$4#Bp[B  
lY tt|J  
lF!PiL  
} >t cEx(  
lgU!D |v  
OmWEa  
public void run() S^p b9~  
{ {\1bWr8!U  
//获得文件长度 &]n }fq  
//分割文件 K& ^qn&  
//实例FileSplitterFetch :zKW[sF  
//启动FileSplitterFetch线程 =figat  
//等待子线程返回 w CLniCt  
try{ z U[pn)pe  
if(bFirst) mgx|5Otg  
{ h76j|1gI  
nFileLength = getFileSize(); %@a;q?/?Nd  
if(nFileLength == -1) La1:WYt  
{ / =6_2t#vA  
System.err.println("File Length is not known!"); M,H8ZO:R  
} ~q566k!Ll!  
else if(nFileLength == -2) G^)]FwTs  
{ @9 S ::  
System.err.println("File is not access!"); #0<pRDXj  
} pE<a:2J  
else L.@$rFhA  
{ YM_[   
for(int i=0;i<nStartPos.length;i++) *g+ ZXB  
{ 7Fo^ :"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /(s |'"6  
} I(~([F2  
for(int i=0;i<nEndPos.length-1;i++) nzaDO-2!  
{ A2ye ^<-C.  
nEndPos = nStartPos[i+1]; (}X5*BB&  
} qWr=Oiu  
nEndPos[nEndPos.length-1] = nFileLength; F!#)l*OX;  
} tjtvO@?1-  
} q$" u<  
3'.3RKV  
n}Z%D-b$  
//启动子线程 vOlfyH>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9]=J+ (M  
for(int i=0;i<nStartPos.length;i++) Y[7prjd  
{ }>@SyE'Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q#AEu xI1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3<XuJ1V&  
nStartPos,nEndPos,i); _=I1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ASy?^Jrs5  
fileSplitterFetch.start(); `"CA$Se8  
} 72~L  ?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ||X3g"2W9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~2rQ80_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >A{Dpsi\  
nEndPos = " + nFileLength); +g?uvXC&  
// fileSplitterFetch[nPos.length-1].start(); Gz{%Z$A~o  
 ri4z^1\  
Fvk=6$d2  
//等待子线程结束 ddN(L`nd  
//int count = 0; .\$A7DD+A  
//是否结束while循环 K.QSt  
boolean breakWhile = false; hGD@v {/  
_(J#RH  
k vZw4Pk  
while(!bStop) [#Apd1S_  
{ eV}"L:bgJ  
write_nPos(); npzp/mcIe)  
Utility.sleep(500); h'em?fN(  
breakWhile = true; =At" Q6-O  
tm5{h{AM  
A^).i_&#  
for(int i=0;i<nStartPos.length;i++) !a UYidd  
{ L<=Dl  
if(!fileSplitterFetch.bDownOver) ]CLM'$  
{ 2R,} j@  
breakWhile = false; KJyCfMH&:@  
break; 1LS1 ZY  
} vW eg1  
} _Vp"G)1Y  
if(breakWhile) R /" f  
break; ;8PO}{rD  
stK}K-=`  
_ab8z]H   
//count++; U)f('zD  
//if(count>4) nxhlTf>3  
// siteStop(); P]n0L4c  
} :qxWANUa  
mWZP.w^-  
"|I.j)  
System.err.println("文件下载结束!"); C~4SPCU  
} J|{50?S{^  
catch(Exception e){e.printStackTrace ();} v|~=rvXFC  
} EGgw#JAi#t  
<vWP_yy  
TO89;O  
//获得文件长度 3}s]F/e  
public long getFileSize() (bv{1 7K  
{ VK*_p EV,}  
int nFileLength = -1; .F$}a%  
try{ uQc("F  
URL url = new URL(siteInfoBean.getSSiteURL()); Mm*V;ADF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,Tar?&C:  
httpConnection.setRequestProperty("User-Agent","NetFox"); &,<,!j)Jr  
!;8Y?c-D  
{.kIC@^O  
int responseCode=httpConnection.getResponseCode(); er24}G8  
if(responseCode>=400) oS$7k3s fj  
{ 6M&ajl`o  
processErrorCode(responseCode); 4vi?9MPz  
return -2; //-2 represent access is error ]cP%d-x}  
} 4+>yL+sC%v  
:k ?`gm$  
{+#{Cha  
String sHeader; \Y"S4<"R  
\?t8[N\_[(  
>b"@{MZ@t  
for(int i=1;;i++) : 8>zo  
{ `AE6s.p?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Sak^J.~G[  
//Utility.log(in.readLine());  ij:a+T  
sHeader=httpConnection.getHeaderFieldKey(i); 0~ nCT&V  
if(sHeader!=null) 7#+Ih-&EQ  
{ `:7r5}(^  
if(sHeader.equals("Content-Length")) |sr\SCx  
{ 5@1h^w v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jt}oq%Bf  
break; ]vB^%  
} Pi=FnS  
} <2@t ~ 9  
else 3HXeBW  
break; ^_v94!a 9  
} i_m& qy<v  
} w uY-f4  
catch(IOException e){e.printStackTrace ();} lwt,w<E$  
catch(Exception e){e.printStackTrace ();} 6!0NFP~b  
j%3 $ytf|p  
KL?<lp"  
Utility.log(nFileLength); ?MSZO]Q4+  
4w%hvJ  
5K9W5hA:D  
return nFileLength; ynra%"sd  
} }Y.@:v j  
j,].88H  
}P%gwgPK  
//保存下载信息(文件指针位置) 4J,6cOuW4  
private void write_nPos() =CFg~8W  
{ +,"[0RH  
try{ ,e$RvFB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yg}L,JJU<  
output.writeInt(nStartPos.length); Rq|5%;1  
for(int i=0;i<nStartPos.length;i++) M.5F|7  
{ 1 c"s+k]9  
// output.writeLong(nPos); B> i^w1  
output.writeLong(fileSplitterFetch.nStartPos); O<!^^7/h0  
output.writeLong(fileSplitterFetch.nEndPos); 6 T~+vT  
} |1ry*~  
output.close(); _d~GY,WTdO  
} 5C*Zb3VG4  
catch(IOException e){e.printStackTrace ();} q{*[uJ}Xc"  
catch(Exception e){e.printStackTrace ();} ^{yb4yQ 0  
} vQXF$/S  
 gHUW1E  
@:hWahMy  
//读取保存的下载信息(文件指针位置) }1CO>a<  
private void read_nPos() PTpCiiA@  
{ |'i ?o  
try{ coaJDg+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (ce)A,;  
int nCount = input.readInt(); [uie]*^  
nStartPos = new long[nCount]; 3S^Qo9S  
nEndPos = new long[nCount]; c?xeBC1-  
for(int i=0;i<nStartPos.length;i++) P'_ aNU  
{ 4b yh,t  
nStartPos = input.readLong(); (#je0ES  
nEndPos = input.readLong(); q{,yas7}  
} +W>tdxOh  
input.close(); $\4Or  
} >>J!|  
catch(IOException e){e.printStackTrace ();} =|-xj h  
catch(Exception e){e.printStackTrace ();} QIN# \  
} @J@bD+Q+0  
I GcR5/3  
d9 8pv%  
private void processErrorCode(int nErrorCode) S!}pL8OE  
{ gJOswN;([  
System.err.println("Error Code : " + nErrorCode); _x#r,1V+D  
} ;NJM3g0I  
Git2Cet  
y7*^H  
//停止文件下载 d7c m?+  
public void siteStop() )^^}!U#|e  
{ H~*[v"  
bStop = true; Q([g1?F9*  
for(int i=0;i<nStartPos.length;i++) wVs|mG"  
fileSplitterFetch.splitterStop(); ',RR*{I  
/ dn]`Ge)  
.Qj`_q6=  
} 2gjA>ET`N  
} \@n/L{}(@  
//负责部分文件的抓取 9Bmgz =8  
**FileSplitterFetch.java z!j`Qoh?V9  
*/ }W%}_UT  
package NetFox; [ 06B)|s  
PsD]gN5"  
Y!s/uvRI  
import java.io.*; qm}7w3I^  
import java.net.*; 8|Y^z_C  
Z=sAR(n}~  
X}bgRzj  
public class FileSplitterFetch extends Thread { kp;MNRc  
`^N;%[c`z  
 Q{Bj(f  
String sURL; //File URL S"Zs'7dy`  
long nStartPos; //File Snippet Start Position aH$*Ue@Q  
long nEndPos; //File Snippet End Position Ap>n4~  
int nThreadID; //Thread's ID D{z=)'/F  
boolean bDownOver = false; //Downing is over en~(XE1  
boolean bStop = false; //Stop identical 'Ph;:EMj  
FileAccessI fileAccessI = null; //File Access interface ;[ zx'e?!  
XJ NKM~  
(}qLxZ/U  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KJkcmF}Q  
{  3i$AR  
this.sURL = sURL; 2Uk8{d  
this.nStartPos = nStart; ,[hJi3xM  
this.nEndPos = nEnd; XAFTLNV>  
nThreadID = id; D 7E^;W)H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BR%:`uiQ<  
} fu&]t8MJC  
nW%c95E  
(jyJ-qe  
public void run() Mo<p+*8u:  
{ }w@nZG ^&  
while(nStartPos < nEndPos && !bStop) aH#|LrdJ  
{ +%~g$#tlJo  
K^vMIoh  
#sHP\|rA  
try{ Yb\36|  
URL url = new URL(sURL); Zj0&/S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JZ7-? o  
httpConnection.setRequestProperty("User-Agent","NetFox"); ixkg,  
String sProperty = "bytes="+nStartPos+"-"; g/yXPzLU  
httpConnection.setRequestProperty("RANGE",sProperty); 1f:k:Y9i  
Utility.log(sProperty); [)=FZF6kG  
Aws TDM  
vtT:c.~d  
InputStream input = httpConnection.getInputStream(); ;g*6NzdA  
//logResponseHead(httpConnection); !14z4]b  
3IxT2@H)  
/L 4WWQ5  
byte[] b = new byte[1024]; ,O+7nByi[V  
int nRead; w?C\YKF7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M>#{~zr  
{ EIfrZg7R  
nStartPos += fileAccessI.write(b,0,nRead); 4c yv 8  
//if(nThreadID == 1) ]9:G3vq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WveFB%@`;  
} td~3N,S  
\NqC i'&  
9+']`=a:  
Utility.log("Thread " + nThreadID + " is over!"); =EJ"edw]%0  
bDownOver = true; .,,73"  
//nPos = fileAccessI.write (b,0,nRead); )Fw)&5B!  
} 8FITcK^  
catch(Exception e){e.printStackTrace ();} qGqu/$bh  
} m @%|Q;  
} U{Z>y?V/  
;z>YwRV  
,L;vN6~  
//打印回应的头信息 wGH@I_cy>  
public void logResponseHead(HttpURLConnection con) UK,P?_e  
{ URgF8?n  
for(int i=1;;i++) =)8Ct  
{ ~e<<aTwN  
String header=con.getHeaderFieldKey(i); 7w*&Yg]  
if(header!=null) / ["T#`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i.]zq  
Utility.log(header+" : "+con.getHeaderField(header)); I1~g?jpH  
else jlBCu(.,_  
break; %K7}yy&9C  
} UJ[a& b  
} d#Ajb  
-wfV  
[Bo$?  
public void splitterStop() 3XtGi<u  
{ YP,PJnJU8  
bStop = true; j+hoj2(  
} rYQ@"o0/Y  
M'iKk[Hjfx  
r `dU (T!  
} ?xZmm%JF  
rUjr'O0  
E,@UM$alP  
/* :F=nb+HZ  
**FileAccess.java _4$DnQ6&  
*//文件访问(定位,写) F.D1;,x  
package NetFox; [!mjUsut*  
import java.io.*; qGCg3u6  
a7G2C oM8  
RzQS@^u*F0  
public class FileAccessI implements Serializable{ ;r"B?]JO  
I;H9<o5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d A{Jk  
RandomAccessFile oSavedFile; %)Dd{|c  
long nPos; /8\&f %E  
0K0=Ob^(e  
|9]K:A  
public FileAccessI() throws IOException WI_mJ/2  
{ W%K8HAP"  
this("",0); !p2,|6Y`y  
} zq r%7U  
5O ;^Mk|  
$#3<rcOq  
public FileAccessI(String sName,long nPos) throws IOException '<S:|$ $  
{ \3?;[xD  
oSavedFile = new RandomAccessFile(sName,"rw"); }p?V5Qp  
this.nPos = nPos; 9?chCO(@  
oSavedFile.seek(nPos); >Eg. c  
} 9= $,]M  
_kX/LR"L+  
wg0.i?R-]  
public synchronized int write(byte[] b,int nStart,int nLen) <L/vNP  
{ h_G Bx|c  
int n = -1; {<[tYZmj.  
try{ .t[ZXrd| 0  
oSavedFile.write(b,nStart,nLen); C+m^Z[  
n = nLen; 1'm`SRX#e  
} (A fbS=[  
catch(IOException e) N%|Vzc  
{ JD`;,Md  
e.printStackTrace (); _XNR um4  
} 8!Mzr1:  
~V"cLTj"  
6ri?y=-c  
return n; NG!cEo:2aa  
} )X!DCL:16  
AYu'ptDNr  
\If!5N  
}  zn;Hs]G  
^ O Xr: P  
wp*&&0O!  
/* $0 S#d@v}  
**SiteInfoBean.java .P :f  
*/ Sb9=$0%\  
package NetFox; q '{<c3&  
V&j.>Y  
{e[pSD6   
public class SiteInfoBean { <Bb<?7q$ld  
2{]S_. zV  
?"<r9S|[O  
private String sSiteURL; //Site's URL 0H&U=9'YT  
private String sFilePath; //Saved File's Path 9eN2)a/  
private String sFileName; //Saved File's Name R ms01m>Y  
private int nSplitter; //Count of Splited Downloading File Pzm!`F^r}  
f'`nx;@X  
LXu"rfp  
public SiteInfoBean() E,D:D3O  
{//nSplitter的缺省值为5 ;ko[(eFN@  
//default value of nSplitter is 5 xAd>",=~  
this("","","",5); BXK::M+  
} fByh";<`P  
['Y+z2k  
$sL|'ZMbS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a[74%L?  
{ Y K?*7  
sSiteURL= sURL; 3 +8"  
sFilePath = sPath; F`BgKH!  
sFileName = sName; |`Oa/\U  
this.nSplitter = nSpiltter; o&XMgY~  
_]D#)-uv}C  
,7fc41O3V  
} nc\C 4g  
gR-Qj  
0n<(*bfW  
public String getSSiteURL() h\u0{!@}  
{ EB29vHAt~  
return sSiteURL; A M1C $  
} 4`UL1)A]  
>\?z37 :T  
^0s\/qyqm  
public void setSSiteURL(String value) g",wkO|  
{ `Ge+(1x  
sSiteURL = value; 4QjWZ Wl  
} aZawBU.:  
s7.p$r  
^0`<k  
public String getSFilePath() /J[H5uA  
{ 0Y6q$h>4  
return sFilePath; jr[<i\!  
} ~ gfA](N  
1(%>`=R8  
uK;K{  
public void setSFilePath(String value) 4j=<p@  
{ yWv<A^C &  
sFilePath = value; Y[ iDX#  
} SvX=isu!.  
OBI+<2`Oc  
t":W.q<  
public String getSFileName() 8NaL{j1`  
{ jNe(w<',P  
return sFileName; 3qAwBVWa  
} {*?sVAvj  
+ %MO7vL  
9@#h}E1$  
public void setSFileName(String value) 2/yXY_L  
{ Wa[x`:cT?u  
sFileName = value; <2)s<S.;  
} `%t$s,TiP  
 cS D._"P  
@,x_i8  
public int getNSplitter() 4pmTicA~  
{ Pv/Pww \  
return nSplitter; MvFM ,  
} 0T9@,scY  
<#+oQ>5s  
0W T#6D  
public void setNSplitter(int nCount) yaH Trh%  
{ F . K2  
nSplitter = nCount; y4xT:G/M  
} KqM!!  
} QU^/[75Ea0  
gEZwW]r-  
"wA0 LH_  
/* \8;Qv  
**Utility.java _4P;+Y  
*/ s<A*[  
package NetFox; LXHwX*`Y  
T*h!d(  
T)WZ_bR  
public class Utility { 5cD XWF  
HQq`pG%m6  
`IEq@Wr#$!  
public Utility() <Ctyht0c.  
{ <jbj/Q )"  
s~S?D{!  
+yzcx3<  
} BJ~ ivT<  
c]A Y  
//线程睡眠 B|cA[  
public static void sleep(int nSecond) x!'7yx  
{ {mNdL J  
try{ ]EB6+x!G  
Thread.sleep(nSecond); ]]>nbgGn#  
} BjM+0[HC  
catch(Exception e) mO#I nTO  
{ +0VG[ c\8  
e.printStackTrace (); @ru<4`h  
} |<sf:#YzY&  
} _1sP.0 t  
(nGkZ}p  
//日志 H{ZLk,  
public static void log(String sMsg)  ylk{!  
{ j5kA^MTG  
System.err.println(sMsg); A:/}`  
} kEO1TS  
|Eb&}m:E$  
4<u;a46Z#M  
public static void log(int sMsg) NdZ)[f:2  
{ C1 W>/?XC  
System.err.println(sMsg); Y+FP   
} XM$GQn]B  
} 9qEOgJ  
dgXg kB'  
#zxd;;p3  
/* @d&g/ccMxd  
**TestMethod.java iAK/d)bq  
*/ %*6RzJO6  
package NetFox; {ih:FcI  
{gsW(T>)  
J;~E<_"Hn  
public class TestMethod { D ZVXz|g  
mmHJ h\2v  
0 sZwdO  
public TestMethod() [UoqIU  
{ ///xx/weblogic60b2_win.exe `$at9  
try{ $.a|ae|K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6+iK!&+=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y1iX!m~)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PcB{ = L  
fileFetch.start(); YZ< NP  
} X@!X6j  
catch(Exception e){e.printStackTrace ();} -,^WaB7u\  
`y2ljIWJ  
9\AS@SH{^T  
} 6}ftBmv  
3T1P$E" m  
Wab.|\c  
public static void main(String[] args) EL7T'zJ$  
{ OF8WDo`  
new TestMethod(); Zi/-~')E  
} @bT3'K-4  
} 9:-T@u  
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