http断点续传简单实现（java)

/* Nw|m"VLb  
**SiteFileFetch.java }~3 %KHT  
*/ {rWFgn4Li  
package NetFox; &0QtHcXpR  
import java.io.*; ^VAvQ(b!:i  
import java.net.*; gyAKjLqqpi  
"8YXF
g  
]eD5It\  
public class SiteFileFetch extends Thread { L#X!.  
Ij}k>qO/2  
+/Q?<*[  
SiteInfoBean siteInfoBean = null; //文件信息Bean zMW[Xx!  
long[] nStartPos; //开始位置 +7|Qd}\X  
long[] nEndPos; //结束位置 K3($
,aB}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )Y:9sd8g7  
long nFileLength; //文件长度 *>f-UNV  
boolean bFirst = true; //是否第一次取文件 KWB;*P C^  
boolean bStop = false; //停止标志 #I|j
Fn9  
File tmpFile; //文件下载的临时信息 yqKERdm  
DataOutputStream output; //输出到文件的输出流 *cnxp-)ub  
UJ8
V%0  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1} h''p  
public SiteFileFetch(SiteInfoBean bean) throws IOException XI*cu\7sy  
{ f0,,<ib.w
 
siteInfoBean = bean; @Nk]f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #pm0T1+jW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gjnTG:}}}+  
if(tmpFile.exists ()) _Z
D8/?2QV  
{ T($6L7 j9  
bFirst = false; BV`,~n:
 
read_nPos(); bcCCvV}6WZ  
} H^\2,x Z  
else U*7Yi-"/*  
{ K oF4e:2>  
nStartPos = new long[bean.getNSplitter()]; m6D]   
nEndPos = new long[bean.getNSplitter()]; HLml:B[F(  
} 69>N xr~k  
KsMC+:`F  
8wQ|Ep\  
pHkhs{/X  
} 39zwPoN>  
Hjtn*^fo^  
!YCus;B~  
public void run() @3@oaa/v  
{ Q-,,Kn  
//获得文件长度 |rg4j  
//分割文件 }3&~YBx;:  
//实例FileSplitterFetch #0wH.\79  
//启动FileSplitterFetch线程 wqyrs|P  
//等待子线程返回 Q+]
9Glz9  
try{ y@?t[A#v  
if(bFirst) fX[6  {  
{ Z?}yPsOb  
nFileLength = getFileSize(); "2~%-;c  
if(nFileLength == -1) RN"O/b}qQ  
{ %W[#60  
System.err.println("File Length is not known!"); K@UQ O  
} TUaW'  
else if(nFileLength == -2) "X7;^yY  
{ Q lg~S1D_v  
System.err.println("File is not access!"); C0bOPn  
} %m5&U6  
else I/ q>c2Pw$  
{ 'eRJQ*0F  
for(int i=0;i<nStartPos.length;i++) %Qc5_of  
{ #^FDFl  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
B}YpIb]d  
} ozr82  
for(int i=0;i<nEndPos.length-1;i++)  T.{sO`  
{ 'QrvkQ  
nEndPos = nStartPos[i+1]; 861!p%y5  
} _:Jra  
nEndPos[nEndPos.length-1] = nFileLength; ^`&?"yj<z  
} Cm5:_K`;]  
} uK5&HdoM  
68k  
X\a*q]"_  
//启动子线程 :Vyr8+]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kA1C&  
for(int i=0;i<nStartPos.length;i++) D<35FD,  
{ 4tb y N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q0l=S+0
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aN/0'V|&ym  
nStartPos,nEndPos,i); 'l| e}eti>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J"&jR7-9  
fileSplitterFetch.start(); WLe9m02r  
} 7Ib/Cm0d|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E =7m@"0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I|#1u7X%]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \~#$$Q-qtU  
nEndPos = " + nFileLength); *Ou)P9~-L  
// fileSplitterFetch[nPos.length-1].start(); ]tzO)c)w;  
zL<<`u?  
[4_JK  
//等待子线程结束 g,0u_$U  
//int count = 0; JGB 9Z   
//是否结束while循环 WE hDep:  
boolean breakWhile = false; wCwJ#-z.=  
C25r3bj  

{
eU
_  
while(!bStop) Qmk}smvH  
{ L`M.Htm8  
write_nPos(); 6_s_2cr  
Utility.sleep(500); 0gEtEH+  
breakWhile = true; <e s>FD  
L:(>O
N  
E(;V.=I  
for(int i=0;i<nStartPos.length;i++) l-Q.@hG  
{ *nPB+
@f  
if(!fileSplitterFetch.bDownOver) DD4fV`:kG  
{ [= GVK  
breakWhile = false;  >Mzk;TM  
break; &%ZiI@O-  
} *XCid_{(  
} o?Wp[{K  
if(breakWhile) h5:>o  
break; m\}8N u  
d0;$k,  
yz CQ  
//count++; jBTXs5q  
//if(count>4) H)Zb_>iV  
// siteStop(); n]N+  
} bHi0N@W!vG  
oBm^RHTZ  
R>ak 3Y  
System.err.println("文件下载结束！"); 1ud+~y$K  
} NiCH$+c\  
catch(Exception e){e.printStackTrace ();} WI?iz-,](  
} 7I,/uv?  
F>0[v|LG  
UA{tmIC\  
//获得文件长度 U%7| iK  
public long getFileSize() ~_z"So'|F_  
{ nJvDkh#h1  
int nFileLength = -1; (L{Kg U&{$  
try{ XM+o e0:[  
URL url = new URL(siteInfoBean.getSSiteURL()); I.M@we/bR}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  b* QRd  
httpConnection.setRequestProperty("User-Agent","NetFox"); /%#LA  
=`b/ip5  
#DN5S#Ic  
int responseCode=httpConnection.getResponseCode(); {x+"Ru~7,  
if(responseCode>=400) Q UQ"2oC  
{ m5G9 B-\?  
processErrorCode(responseCode); TJB)]d<  
return -2; //-2 represent access is error {G+pI2^  
} O%g%*9  
X/ \5j   
$ON4nx  
String sHeader; abHW[VP9  
VPKoBJ&  
Nvlfi8.  
for(int i=1;;i++) nj (/It  
{ `+4>NT6cu9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,<^7~d{{3m  
//Utility.log(in.readLine()); UogkQ& B  
sHeader=httpConnection.getHeaderFieldKey(i); c\n&Z'vK  
if(sHeader!=null) ",b3C.  
{ \8~P3M":c  
if(sHeader.equals("Content-Length")) H9x
,C/r,  
{ q*Hf%I"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w/L^w50pt  
break; 5kK:1hH
7  
} gbf-3KSp^  
} y;!qE~!3  
else hrT_0FZV  
break; %<g(EKl  
} |NbF3 fD  
} "funFvY  
catch(IOException e){e.printStackTrace ();} !Od?69W, $  
catch(Exception e){e.printStackTrace ();} Qg7rkRia  
aw0;  
H O^3v34ZO  
Utility.log(nFileLength); ~{#$`o=  
>t[beRcR6  
Wz}8O]#/.  
return nFileLength; ];-DqK'  
} qfO=_z ES  
aKLA_-
E  
dFd^@b  
//保存下载信息（文件指针位置） D^?jLfW8  
private void write_nPos() `m~x*)L#  
{ _^)Wrf+  
try{ 4@K9%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6I$laHx?  
output.writeInt(nStartPos.length); LP{{PT.&X  
for(int i=0;i<nStartPos.length;i++) 0Cox+QJt  
{ K+0&~XU  
// output.writeLong(nPos); YWV"I|Z  
output.writeLong(fileSplitterFetch.nStartPos); U{IY F{;@  
output.writeLong(fileSplitterFetch.nEndPos); 7j>NUx=j3  
} ^4+ew>BLSv  
output.close(); ;g3z?Uz)  
} Q^&oXM'x/i  
catch(IOException e){e.printStackTrace ();} 5wy1%/;  
catch(Exception e){e.printStackTrace ();} hPCt-  
} KjrUTG0oA  
~wMdk9RQ  
wD|3Czc  
//读取保存的下载信息（文件指针位置） *4i)aj  
private void read_nPos() Zu4|
1W  
{ L|y4u;-Q  
try{ F{:ZHCm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); pjC2jlwm*  
int nCount = input.readInt(); b7 pD#v  
nStartPos = new long[nCount]; X5@SLkJ-`  
nEndPos = new long[nCount]; >-2eZ(n)"  
for(int i=0;i<nStartPos.length;i++) [79 eq=  
{ m;=wQYFr{I  
nStartPos = input.readLong(); Mp*S+Plp  
nEndPos = input.readLong(); Wc}opp  
} xiu?BP?V  
input.close(); b`NXe7A  
} jV(\]g"/=  
catch(IOException e){e.printStackTrace ();} >&@hm4  
catch(Exception e){e.printStackTrace ();} `1cGb*b/  
} p2c4 <f-M  
3:">]LMi  
wq[\Fb`  
private void processErrorCode(int nErrorCode) [0_JS2KE  
{ `EV"
/&`  
System.err.println("Error Code : " + nErrorCode); &1O!guq%  
} 9Tgl/}q)  
[m9Pt]j@  
]L'FYOfrpx  
//停止文件下载 U({20  
public void siteStop() hEO#uAR^Z  
{ 4H7 3a5f  
bStop = true; -=W"  
for(int i=0;i<nStartPos.length;i++) dXkgWLI~  
fileSplitterFetch.splitterStop(); "4VC:"$f  
| HkLl^  
M*DFtp<  
} x=+R0ny  
} oYYns%r}{  
//负责部分文件的抓取 _
xg4;W6M=  
**FileSplitterFetch.java }pE8G#O&  
*/ \htL\m^$9  
package NetFox; q|E0Y   
 R^%uEP  
*cjH]MQ0Ak  
import java.io.*;  u/Os  
import java.net.*; ~c e?xr|  
'%W'HqVcG1  
U6hT*126  
public class FileSplitterFetch extends Thread { 4Xna}7  
fI{ZElPp  
u9
WQ0.  
String sURL; //File URL pNOVyyo>BW  
long nStartPos; //File Snippet Start Position _3q%  
long nEndPos; //File Snippet End Position h[5<S&  
int nThreadID; //Thread's ID KY)rkfo B  
boolean bDownOver = false; //Downing is over |{#=#3X  
boolean bStop = false; //Stop identical
T5m
dC  
FileAccessI fileAccessI = null; //File Access interface Hx}K wS  
-qki^!Y?  
89I[Dg;"u  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *.
H1m{V  
{ xS~OAcxg  
this.sURL = sURL; LPjsR=xi  
this.nStartPos = nStart; DVu_KT[Hd  
this.nEndPos = nEnd; +O<0q"E  
nThreadID = id; {x{/{{wzv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~|j:xM(i  
} /h4 ::,  
pRsYA7Ti  
<Sxsmf0"  
public void run() cz8%p;F:  
{ m6%csh-N1  
while(nStartPos < nEndPos && !bStop) `O-LM
e  
{ F{1;~Yg%  
}$K2h*  
%-~W|Y  
try{ \]y4e^FZZ  
URL url = new URL(sURL); uV]4C^k;`[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,hj5.;
M  
httpConnection.setRequestProperty("User-Agent","NetFox"); >U~B"'!xV  
String sProperty = "bytes="+nStartPos+"-"; ?[4!2T,Ca  
httpConnection.setRequestProperty("RANGE",sProperty); Ua.7_Em  
Utility.log(sProperty); )PC(1Zn  
;4jRsirx9  
Mr}]P(4h  
InputStream input = httpConnection.getInputStream(); %21i#R`E  
//logResponseHead(httpConnection); =-M)2&~L~  
nZF(92
v  
9N9dQ}[:g  
byte[] b = new byte[1024]; 0phO1h]2S)  
int nRead; .xtjB8gc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B/IPG~aMEZ  
{ !P7##ho0  
nStartPos += fileAccessI.write(b,0,nRead); o C]tEXJ  
//if(nThreadID == 1) c65_E<5Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S- Mh0o"  
} :kycIM]s  
0y$aGAUm  
sPCp20x:y8  
Utility.log("Thread " + nThreadID + " is over!"); 9`J!]WQ1[  
bDownOver = true; 8ALvP}H  
//nPos = fileAccessI.write (b,0,nRead); -e=p*7']  
} LGN,8v<W(  
catch(Exception e){e.printStackTrace ();} /Kmzi9j+  
} (wmMHo|  
} X\SZ Q[gN  
!GkwbHr+p  
im&E\`L7  
//打印回应的头信息 -b>"2B?  
public void logResponseHead(HttpURLConnection con) 8uyUvSB  
{ I)~&6@Jn  
for(int i=1;;i++) 15Vb`Vf`N  
{ #C?
T  
String header=con.getHeaderFieldKey(i); %K^l]tWa@  
if(header!=null) \Nc/W!r*9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); TlExw0i!  
Utility.log(header+" : "+con.getHeaderField(header)); $|v_ pjUu]  
else Lm<"W_  
break; j(
|G
) F  
} T ,, Ao36  
} DPvM|n`TW  
Bcx-t)[  
n{F$,a  
public void splitterStop() D_GIj$%N[  
{
yD iL  
bStop = true; q<>  
} W G2 E3y  
JZp*"UzQr  
)^UM8 s  
} DpIv <m]  
OL]^4m  
\F%5TRoC  
/* iw<#V&([J  
**FileAccess.java r}
OK3J  
*//文件访问(定位，写) [h8j0Q@Q  
package NetFox; N=K|Nw  
import java.io.*; v*%#Fp,g8  
LTu cs}  
v\*43RL  
public class FileAccessI implements Serializable{ jsSxjf;O  
qr%9Sdvx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "J]_B  
RandomAccessFile oSavedFile; nAn/Vu  
long nPos; o+W5xHe^1  
]=p@1  
}LS:f,1oGp  
public FileAccessI() throws IOException #Ag-?k  
{ ko2Kz k  
this("",0); Ghgx8 ]e  
} I]P'wav~O  
E6
n3[Z  
kVs'>H@FY  
public FileAccessI(String sName,long nPos) throws IOException =>Y b~r71  
{ &LE,.Q34  
oSavedFile = new RandomAccessFile(sName,"rw"); <,d.`0:y  
this.nPos = nPos; $x5P5^Y  
oSavedFile.seek(nPos); n(.y_NEgV!  
} ]gYnw;W$  
2Yt#%
bj7^  
U@+ @Mc  
public synchronized int write(byte[] b,int nStart,int nLen) uR{HCZ-  
{ u2 a U0k:  
int n = -1; FR9<$  
try{ X l#P@60  
oSavedFile.write(b,nStart,nLen); TEl:;4  
n = nLen; >TUs~  
} V6"
<lK8"  
catch(IOException e) 7QP%Pny%  
{ {hB7F"S  
e.printStackTrace (); |ofegO}W7  
} O(;K]8  
*@fR36  
> 4ex:Z  
return n; AOQim
jW9a  
} )n 1b  
 6\ /x  
@cdd~9w  
} %3scz)4$  
R0y={\*B5k  
KE:PRX  
/* 'EJ

8)2  
**SiteInfoBean.java /*g3TbUs  
*/ WyVFhAuU  
package NetFox; Eq^k@  
k|Vq-w  
Zh`lC1l'  
public class SiteInfoBean { ~\`lbGJ7?  
y0>as
l  
'M185wDdAl  
private String sSiteURL; //Site's URL 7PO3{I  
private String sFilePath; //Saved File's Path 6lO]V=+  
private String sFileName; //Saved File's Name VTySKY+  
private int nSplitter; //Count of Splited Downloading File qEr2Y/:i"  
r H;@N  
q}e"E cr  
public SiteInfoBean() 1VK?Svnd  
{//nSplitter的缺省值为5 0ZPwE
P  
//default value of nSplitter is 5 EZaWEW  
this("","","",5); /kE3V`es  
} 9@ [R>C  
9K~2!<  
SV16]V
c  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =8$//$  
{ | 2BIAm]  
sSiteURL= sURL; 1eQ9(hzF  
sFilePath = sPath; Sj
;B1&  
sFileName = sName; [hA%VF.9  
this.nSplitter = nSpiltter; "l!WO`.zp=  
#pP4\n-~hU  
F<
q'ivj:w  
} *JE%bQ2Q  
Twyx(~'&R  
R/r)l<X@  
public String getSSiteURL() 5=tvB,Ux4  
{
3TqC.S5+  
return sSiteURL; >f#P(  
} w~a^r]lPW
 
PVH
JIB  
[2#5;')  
public void setSSiteURL(String value) )z-)S  
{ zvV<0 Z  
sSiteURL = value; CI"7* z_  
} "OF4#a17  
!spp*Q)#\  
Ig75bZz   
public String getSFilePath() occ^bq  
{ T%~w~stW  
return sFilePath; 01N"  
} w naP?|/  
{'VP_ZS1v  

ZC 7R f  
public void setSFilePath(String value) nf&PDv1  
{ 
;q]Jm  
sFilePath = value; [ qt hn[3  
} O=UXe]D  
ntbl0Sk  
L;zwqdI  
public String getSFileName() k8
H@0p  
{ {Vw+~8  
return sFileName; IWcgh`8  
} OV3l)73?t  
v+uq  
HE58A.Q&  
public void setSFileName(String value) M#X8Rs1`  
{ a0I+|fR  
sFileName = value; zW
KnkIit,  
} 1BT]_ cP  
*I
6z;.#  
|57u;  
public int getNSplitter() OE
' ?3S  
{ }U3+xl6g  
return nSplitter; {T4F0fu[eR  
} O 4zD >O  
zaWy7@?  
BrF/-F  
public void setNSplitter(int nCount) VuA7rIF$66  
{ pgbm2mT9  
nSplitter = nCount; 0$)s? \  
} EdFCaW}""  
} >KHR;W03  
gY\X?  
-&4>>h9_  
/* <knf^D<"  
**Utility.java $/;D8P5/&=  
*/ nZZNx  
package NetFox; JPQWRK^  
|,3s]b`  
f%vJmpg  
public class Utility { !v/5G_pr  
2N*XzVplN  
F.5'5%  
public Utility() Z(DCR/U=(>  
{ ~C[p}MED  
S3#NGBZ/  
*69{#qN  
} -e<d//>  
e RY2.!  
//线程睡眠 aT}Mn(F*?  
public static void sleep(int nSecond) ^X-3YhJ4U  
{ <xpOi&l  
try{ R_9&V!fl  
Thread.sleep(nSecond); S(NH# ^  
} t8X$M;$  
catch(Exception e) u=_"*
:}  
{ qLrvKoEX2  
e.printStackTrace (); 58xaVOhb  
} Ku;|Dz/=o  
} \f| Hk*@  
DV+M;rs  
//日志 ?bFP'.  
public static void log(String sMsg) k1tJ$}  
{ X&C&DTB  
System.err.println(sMsg); ^(z7?T  
} vJZ0G:1  
8vQGpIa,
 
\H<gKZquR  
public static void log(int sMsg) @1+C*  
{ 8VG6~>ux'>  
System.err.println(sMsg); ^n8ioL\*i  
} AI KLJvte  
} -& Qm"-?:  
MJ5Ymt a  
FY;\1bt<<  
/* MTBHFjXO  
**TestMethod.java k3[rO}>s  
*/ u.v 5!G  
package NetFox; _N8Tu~lqV  
*R9s0;&:  
be&5vl  
public class TestMethod { L8OW@)|  
6Gt~tlt:L  
9%fd\o@X  
public TestMethod() VnlgX\$}  
{ ///xx/weblogic60b2_win.exe )ph**g  
try{ OJ#ehw<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WFWQ;U{|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EQQ/E!N8l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b"D? @dGB,  
fileFetch.start(); tG8)!  
} Ah^0FU%!g  
catch(Exception e){e.printStackTrace ();} ed3d 6/%HR  
9Z?P/ o  
ggluQGA  
} l^`& Tnzv  
`Fn"%P!  
q/T(s  
public static void main(String[] args) 1XfH,6\8i  
{ {u!Q=D$3  
new TestMethod(); L'i0|_  
} eAqSY s!1  
} E}Ir<\  
点击下载更多相关资料