http断点续传简单实现（java)

/* ~Rr~1I&mR,  
**SiteFileFetch.java }B1!gz$YNO  
*/ (I./ Uu%  
package NetFox; }1upi=+aE  
import java.io.*; 1aTB%F  
import java.net.*; :*KHx|Q  
L'kmNVvYN  
P ! _rEV  
public class SiteFileFetch extends Thread { ;&)-;l7M  
@!1x7%]G  
BSVx
N  
SiteInfoBean siteInfoBean = null; //文件信息Bean c3CWRi`LE  
long[] nStartPos; //开始位置 wY_)y  
long[] nEndPos; //结束位置 _/tHD]um  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9c("x%nLpB  
long nFileLength; //文件长度 .P"D  
boolean bFirst = true; //是否第一次取文件 c(~[$)i6  
boolean bStop = false; //停止标志 T]c%!&^_  
File tmpFile; //文件下载的临时信息 lx7Q.su
'  
DataOutputStream output; //输出到文件的输出流 &:`U&06q  
(P:<t6;+  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #n8IZ3+
  
public SiteFileFetch(SiteInfoBean bean) throws IOException &*aIEa^  
{ 6g)GY"49  
siteInfoBean = bean; ,JQp'e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]'=)2 .}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); W}mn}gTQ  
if(tmpFile.exists ()) >: g3k  
{ R)m'lMi|  
bFirst = false; \r+8qC[,  
read_nPos(); BNs@n"k  
} V6,H}k  
else Xx>X5Fy  
{ OL^l 3F  
nStartPos = new long[bean.getNSplitter()]; ,]d/Q<  
nEndPos = new long[bean.getNSplitter()]; mrF58Uq;A  
} z+n,uHs  

Jh!I:;/  
)`(p
9
@,V  
#$8%
w  
} ",KCCis  
$cU!m(SILQ  
$arK(  
public void run() YF>m$?;  
{ #6HA\dE  
//获得文件长度 t,+nQ9  
//分割文件 )u`[6,d  
//实例FileSplitterFetch `M^= D&Bf  
//启动FileSplitterFetch线程 .E8_Oz  
//等待子线程返回 Su/6Q$0 t  
try{ SSWP~ t  
if(bFirst) :x4|X8>  
{ wMg0>  
nFileLength = getFileSize(); !`Hd-&}bYz  
if(nFileLength == -1) fy@<&U5rg  
{ %2{%Obp'  
System.err.println("File Length is not known!"); |#cm`v  
} =V-|#j  
else if(nFileLength == -2) TI,&!E?;  
{ FwkuC09tI  
System.err.println("File is not access!"); HOJs[m
qB%  
} Ku}Z  
else ^<a t'jk6  
{ gL*>[@RO  
for(int i=0;i<nStartPos.length;i++) _8F`cuyW  
{ q%"VYt4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); st:`y=F_  
} os:A]  
for(int i=0;i<nEndPos.length-1;i++) Sp;G'*g  
{ Vg>dI&O  
nEndPos = nStartPos[i+1]; ic#`N0s?  
} MS 81sN\d  
nEndPos[nEndPos.length-1] = nFileLength; 8h*Icf  
} 'R'*kxf  
} V8C:"UZ;  
pUQ/03dp  
p;3O#n-_  
//启动子线程 %,@e^3B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zkuU5O  
for(int i=0;i<nStartPos.length;i++) eo?;`7  
{ o.!~8mD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7`zHX&-W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?IqQ-C)6D  
nStartPos,nEndPos,i); OuID%p"O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ogHCt{'  
fileSplitterFetch.start(); fPR1f~r  
} `tA" }1;ka  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "8x8UgG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iXVe.n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1AM!8VR2  
nEndPos = " + nFileLength); $!-c-0ub  
// fileSplitterFetch[nPos.length-1].start(); :*Z4yx  
4gz H8sF  
K<SyC54  
//等待子线程结束 ( u\._Gwsx  
//int count = 0; %InA+5s`  
//是否结束while循环 $0>60<J  
boolean breakWhile = false; %7IugHH9y  
p93r'&Q  
%,}A@H,  
while(!bStop) j7$e28|_n  
{ *rs5]U<  
write_nPos(); c1k/UcEcg~  
Utility.sleep(500); M3c$=>  
breakWhile = true; e.7EU  
@s ?  
l1OE!W W  
for(int i=0;i<nStartPos.length;i++) P2BWuhF  
{ +./H6!  
if(!fileSplitterFetch.bDownOver) e,vvzso  
{ ]6(N@RC  
breakWhile = false; .f%fHj  
break; K1"*.\?F  
} V3Q+s8OIF  
} bMg(B-uF7  
if(breakWhile) -D  
break; !;Yg/'vD-  
cl=EA6P\X  
cl[BF'.H  
//count++; 5\5/   
//if(count>4) Y)0*b5?1r  
// siteStop(); DS.RURzd{r  
} AS'R?aX|C  
/YW>*?"N  
CrC^1K  
System.err.println("文件下载结束！"); ]@j*/IP  
} %Gz0^[+  
catch(Exception e){e.printStackTrace ();} ~?4PBq  
} ZkRx1S"m  
rzhWw-GY  
J%v=yBC2  
//获得文件长度 +%T\`6  
public long getFileSize()  Ch&a/S}  
{ ]'!f28Ng-  
int nFileLength = -1;
0%&1\rm+j  
try{ g]<4&)~  
URL url = new URL(siteInfoBean.getSSiteURL()); vM*-D{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y~AVei&  
httpConnection.setRequestProperty("User-Agent","NetFox"); VRWAm>u  
fHE<(  
*}F3M\  
int responseCode=httpConnection.getResponseCode(); b~KDP+Ri  
if(responseCode>=400) Q]Y*K  
{ ]qethaNy  
processErrorCode(responseCode); [,t*Pfq'W8  
return -2; //-2 represent access is error gPNZF\ r  
} (6?9BlH~  
q>_/u"  
R} eN@#"D  
String sHeader; kO.%9wFbz  
=x%dNf$e{W  
2h|MXI\g  
for(int i=1;;i++) 4ni<E*  
{ #C~+JL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); rq8K_zp  
//Utility.log(in.readLine()); <Swt);  
sHeader=httpConnection.getHeaderFieldKey(i); Qi,j+xBp  
if(sHeader!=null) [w>$QR  
{ 1-%fo~!l  
if(sHeader.equals("Content-Length")) a,@]8r-"  
{ ~("5yG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); YIn',]p:  
break; ;(f)&Yom  
} .*@;@06?
 
} FOv=!'So  
else a]JYDq`,3  
break; BWeA@v  
} [pC$+NX  
} 3c#BKHNC
 
catch(IOException e){e.printStackTrace ();} fM]+SMZy  
catch(Exception e){e.printStackTrace ();} @K\~O__  
q}`${3qQ3  
nW PF6V>  
Utility.log(nFileLength); /7aBDc-v  
=e/9&993  
-V-RP;">  
return nFileLength; [.O?Z=5a[V  
} V, Z|tB^  
s1MErd  
,~aQL  
//保存下载信息（文件指针位置） [;r)9mh7  
private void write_nPos() 1t:Q_j0Ym  
{ ;kFDMuuO  
try{ *;l]8.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H7z,j}l  
output.writeInt(nStartPos.length); p#01gB  
for(int i=0;i<nStartPos.length;i++) 09X01X[  
{  ,V,`Jf  
// output.writeLong(nPos); l7XUXbYp&=  
output.writeLong(fileSplitterFetch.nStartPos); 03|PYk 6EW  
output.writeLong(fileSplitterFetch.nEndPos); \l'm[jy>  
} Lz
`E;k^  
output.close(); \s/s7y6b+  
} oiF}?:7Q7  
catch(IOException e){e.printStackTrace ();} ^ssK  
catch(Exception e){e.printStackTrace ();} lW+\j3?Z$  
} m;H.#^b*  
c&r70L,  
8>trS=;n  
//读取保存的下载信息（文件指针位置） 8|):`u  
private void read_nPos() k52/w)Ro,$  
{ )bS~1n_0  
try{ wF IegC(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Sc>,lIM  
int nCount = input.readInt(); S'|,
oUWDb  
nStartPos = new long[nCount]; bV(Y`g  
nEndPos = new long[nCount]; ujDd1Bxf?  
for(int i=0;i<nStartPos.length;i++) C\S3Gs  
{ T_i:}ul  
nStartPos = input.readLong(); $*SW8'],`  
nEndPos = input.readLong(); >sfRI]OG  
}
whmdcVh.  
input.close(); n(b(yXYm]  
} 4~k\j  
catch(IOException e){e.printStackTrace ();} J4QXz[dG  
catch(Exception e){e.printStackTrace ();} 931bA&SL=/  
} %=n!Em(  
`Bo*{}E  
OglEt["  
private void processErrorCode(int nErrorCode) n)L*  
{ aO]ZZleNS  
System.err.println("Error Code : " + nErrorCode); Z8# (kmBdB  
} kY&k-K\  
'z0:C
cbj  
sR(9IW-  
//停止文件下载 r;/4F/6"  
public void siteStop() {%<OD8>p  
{ &qMPq->  
bStop = true; M2HomO/X)  
for(int i=0;i<nStartPos.length;i++) hXfQ)$J  
fileSplitterFetch.splitterStop(); H(R1o~  
V[{6e  
CpA|4'#  
} 9)y/:sO<P  
} _76PIR{an  
//负责部分文件的抓取 yL%K4$z  
**FileSplitterFetch.java t`WB;o!  
*/ w QgoN%  
package NetFox; ||T2~Q*:y  
8 BY j  
W0(_~  
import java.io.*; O*eby*%h  
import java.net.*; ~"!]
3C,L  
AuUde$l_  
`NnUyQ;T
 
public class FileSplitterFetch extends Thread { ?i)f^O  
l,R/Gl  
XxT#X3D/,"  
String sURL; //File URL Ager$uC  
long nStartPos; //File Snippet Start Position N96jJk  
long nEndPos; //File Snippet End Position ~Fe${2
 
int nThreadID; //Thread's ID g'pK  
boolean bDownOver = false; //Downing is over +1Vjw'P  
boolean bStop = false; //Stop identical CAWA3fcQp  
FileAccessI fileAccessI = null; //File Access interface *meZ8DV2DH  
c;%_EN%  
`sUZuWL_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7Ilm{@b=  
{ N/]o4o  
this.sURL = sURL; #hW;Ju73  
this.nStartPos = nStart; sSOOXdnGG  
this.nEndPos = nEnd; 8yRJD[/S  
nThreadID = id; r>dwDBE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _9faBrzd  
} fXXr+Mor  
*"R|4"uy  
YsG%6&zEq  
public void run() sC27F
Vwo
 
{ /,1D)0  
while(nStartPos < nEndPos && !bStop) \X<bH&
x:z  
{ jYx38_5e  


-#0qV:D  
tna .52*/  
try{ @xQgY*f#  
URL url = new URL(sURL); V\6=ySx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VOKZ dC-  
httpConnection.setRequestProperty("User-Agent","NetFox"); p%iGc<vHX  
String sProperty = "bytes="+nStartPos+"-"; bsuus R9W  
httpConnection.setRequestProperty("RANGE",sProperty); So{x]x:f  
Utility.log(sProperty); sqla}~CiX  
V7
GRA#|  
flk=>
h|  
InputStream input = httpConnection.getInputStream(); rE iKi  
//logResponseHead(httpConnection); #?5 (o  
8 ![|F:  
,O.3&Nz,c  
byte[] b = new byte[1024]; -c(F1l  
int nRead; 0FGe=$vD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Uh.oErHQD  
{ HqI t74+  
nStartPos += fileAccessI.write(b,0,nRead); hD\rtW  
//if(nThreadID == 1) _Bj)r}~7#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `o<' x.I  
} =2
[7
 E  
>QA uEM  
)_1zRT|9  
Utility.log("Thread " + nThreadID + " is over!"); HKF H/eV  
bDownOver = true; Kpb#K[(]&  
//nPos = fileAccessI.write (b,0,nRead); =fu :@+  
} w<zIAQN  
catch(Exception e){e.printStackTrace ();} Ks=>K(V6  
} Z&ZP"P4  
} =NOH:#iQ  
[OHxonU  
i\1TOP|h  
//打印回应的头信息 T~QWRBO  
public void logResponseHead(HttpURLConnection con) 9!T[Z/}T  
{ *j]9vktH  
for(int i=1;;i++) X'%E\/~u  
{ M9EfU  
String header=con.getHeaderFieldKey(i); Lk~ho?^`  
if(header!=null) OTC!wI g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pF&(7u  
Utility.log(header+" : "+con.getHeaderField(header)); pcau}5 .  
else !g Z67  
break; thV>j9'  
} RMX:9aQ3F  
} Sczc5FG  
}tsYJlh5  
8dV=[+  
public void splitterStop() /<E5"Mm%  
{ Ge,;8N88  
bStop = true; Xua+cVc\y  
} 
!vX D  
^ s1Q*He  
a-l;vDs  
} $"0MU  
HOw-]JSP2  
m0LTx\w!  
/* Nndddk`  
**FileAccess.java j*F`"df  
*//文件访问(定位，写) gT$Ju88  
package NetFox; <.p
U,T/  
import java.io.*; #Xhdn\7  
P/xKnm~  
]d,S749(s  
public class FileAccessI implements Serializable{ SxdE?uCUS  
(ohq0Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lrnyk(M}Q.  
RandomAccessFile oSavedFile; *F ?8c  
long nPos; /TZOJE(2j  
Qi_>
Mg`x  
U Z.=aQ}M  
public FileAccessI() throws IOException (rkyWz  
{ O<96/a'  
this("",0); RRmLd/(  
} 1&^MfP}  
d@ Y}SWTB  
]04e1F1J  
public FileAccessI(String sName,long nPos) throws IOException QA2borfy  
{ Ynp{u`?  
oSavedFile = new RandomAccessFile(sName,"rw"); ,oaw0Vw  
this.nPos = nPos; z74
in8]  
oSavedFile.seek(nPos); ~vXa
qCX  
} 4D['^q  
ZQ)>s>-  
Yu?95qktP  
public synchronized int write(byte[] b,int nStart,int nLen)
<,3^|$c%  
{ %6L^2 X  
int n = -1; b8LoIY*  
try{ fQL"O}Z  
oSavedFile.write(b,nStart,nLen); 1U^A56CN  
n = nLen; YhOlxON
 
} N-I5X2  
catch(IOException e) nA P.^_K  
{ t]$P1*I  
e.printStackTrace (); Eq$&qV-?(  
} w4W_iaU  
vz^<YZMu  
q-]`CW]n  
return n; !PrwH
;  
} _@ *+~9%8p  
wNQ*t-K  
p3]_}Y D[#  
} #+$G=pS'v  
?*?RP)V  
S/Fkw4%  
/* k$H%.l;E  
**SiteInfoBean.java H|RT?Q  
*/  PZ{Dv'C  
package NetFox; cgl*t+o&  
9AxCiT.  
w=^`w:5X  
public class SiteInfoBean { w QNxL5B  
Bn61AFy`  
R zf  
private String sSiteURL; //Site's URL ua5OGx  
private String sFilePath; //Saved File's Path Kv.>Vf.T}_  
private String sFileName; //Saved File's Name .so[I
 
private int nSplitter; //Count of Splited Downloading File jy giG&H  
=+-Yxh|*  
Ku\Y'ub  
public SiteInfoBean() 0A,]$Fzt  
{//nSplitter的缺省值为5 F)s{PCl  
//default value of nSplitter is 5 w3=%*<  
this("","","",5); AtF3%Zv2  
} Ix(?fO#uNF  
Gm9hYhC8  
?[)}l9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zX0mdx<|<  
{ uiJS8(Cb  
sSiteURL= sURL; g.'yZvaP  
sFilePath = sPath; OCZ[D{i9@  
sFileName = sName; x9x E&  
this.nSplitter = nSpiltter; 87:!C5e}  
GN!qyT  
F)
+{AQL  
} d}JP!xf%  
6KVnnK  
/ODXV`3QYI  
public String getSSiteURL() |1ST=O7.LH  
{ +)j
1
.X  
return sSiteURL; h$.:Uj8/  
} _)]+hUwY  
N\HQN0d9  
tID%}Zv  
public void setSSiteURL(String value) abJ" [  
{ AJSx%?h:6  
sSiteURL = value; X66VU  
} ]da^xWK  
INkD=tX  
?Y:8eD"*  
public String getSFilePath() >nw++[K_  
{ n>A98NQ  
return sFilePath; 2Fz|fW_  
} VxY+h`4#  
(y?ITz9  
=QK$0r]c'k  
public void setSFilePath(String value) wMdal:n^  
{ GrTulN?  
sFilePath = value; `)T~psT  
} es>W$QKlo  
yv\#8I:qh  
9*E7}b,  
public String getSFileName() txcf=)@>V  
{ g8w2Vz2/  
return sFileName; )ZBY* lk9  
} YKE46q;J  
++aL4:  
)u/H>;L P  
public void setSFileName(String value) 2*N_5&9mE  
{ OM|Fwr$  
sFileName = value; .Wq@gV  
} K"b`#xN(t  
ZR$'u%+g'  
Yr w$  
public int getNSplitter() ?W0)nQU  
{ ^':!1  
return nSplitter; j:,NE(DF  
} F:D orE  
Rb%%?*|  
$&"V^@  
public void setNSplitter(int nCount) NM0tp )h  
{ ZxlAk+<]  
nSplitter = nCount; aB]m*~  
} "Vr[4&`  
} ]D@0|  
l#lF +Q;  
&q`q4g&7  
/* ,(.MmP`  
**Utility.java F[
4;Xq  
*/ MB%Q WU  
package NetFox; \~BDm  
f8SL3+v  
Dk+&X-]6x5  
public class Utility { kl
"+YF5/  
4n %?Y
Q[t  
kKPi:G52F  
public Utility() HLBkR>e  
{ ?%VI{[y#>  
Ov#=]t5  
I+!:K|^
  
} ?H_LX;r  
>yXN,5d[  
//线程睡眠 2P]L9'N{Y  
public static void sleep(int nSecond) CH fVQ|!\  
{ :>aQ~1f>]  
try{ #-8\JEn  
Thread.sleep(nSecond); / }Rz=&  
} }lK3-2Pk  
catch(Exception e) gJ;_$`  
{ L:(1ZS  
e.printStackTrace (); .<z!3O&L  
} dgDy5{_  
} r?CI)Y;  
0QvT
 
//日志 ,=aJVb=C  
public static void log(String sMsg) ifo7%XPcg  
{ 5OO'v07b  
System.err.println(sMsg); R
Jy=pNztm  
} V
R  
ltkI}h,e  
RZe'Kw -  
public static void log(int sMsg) =C
L} $_  
{ 1yV: qp  
System.err.println(sMsg); wZ4t
CZA  
} sz @p_Z/  
} u
Nn[[LS  
:K ~  
H33i*][H  
/* Ne$"g[uFU  
**TestMethod.java Y-'78BJk  
*/ UxD5eJJ  
package NetFox; Kf 2jD4z}  
fK&e7j`qO  
@:tj<\G]  
public class TestMethod { G&;j6<hl  
+dBz`WD  
LTJc,3\,  
public TestMethod() % aUsOB-RV  
{ ///xx/weblogic60b2_win.exe >HPdzLY?  
try{ DAg58 =qJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RNPbH
.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N$xtHtz8"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); SxK:]Aw  
fileFetch.start(); kQaSbpNmH  
} vA)O{W\o  
catch(Exception e){e.printStackTrace ();} k8,?hX:  
l88A=iLgv  
kD) $2I?  
} }pa9%BQI  
4d_s%n?C  
M7>(hVEAW'  
public static void main(String[] args) Bm\qxQ  
{ =<@\,xN>C  
new TestMethod(); x f4{r+  
} @HBEt^!  
} +3i7D  
点击下载更多相关资料