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http断点续传简单实现(java)

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/* Rqwzh@}  
**SiteFileFetch.java WI]o cF  
*/ ^[%%r3"$C  
package NetFox; =%'`YbD$  
import java.io.*; ZmOfEg|h\  
import java.net.*; R52I= a5,*  
zF5uN:-s  
3@5=+z~CW  
public class SiteFileFetch extends Thread { 3=-4%%[M@  
G-9iowS/A  
?#yV3h|Ij  
SiteInfoBean siteInfoBean = null; //文件信息Bean rkiT1YTY  
long[] nStartPos; //开始位置 )54%HM_$k  
long[] nEndPos; //结束位置 Fnk_\d6Ma  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v]__%_  
long nFileLength; //文件长度 ?+T^O?r|O  
boolean bFirst = true; //是否第一次取文件 \{Q?^E  
boolean bStop = false; //停止标志 0$7.g!h?  
File tmpFile; //文件下载的临时信息 VqL.iZ-  
DataOutputStream output; //输出到文件的输出流 +[SgO}sF  
XeBP`\>Ve  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) x0 d~i!d  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9qS"uj  
{ cRX~z  
siteInfoBean = bean; >0p$(>N]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }j,[ 1@S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $gBd <N9|c  
if(tmpFile.exists ()) jxJv.  
{ 0]HYP;E"U  
bFirst = false; (98Nzgxgx}  
read_nPos(); :eo  
} Qt]Q: 9I[  
else s=?g\oR  
{ ]%Zz \Q  
nStartPos = new long[bean.getNSplitter()]; NEa>\K<\  
nEndPos = new long[bean.getNSplitter()]; FKe,qTqa  
} 2lL,zFAq  
PRNoqi3sY  
Kx_h1{  
EyY.KxCB  
} ~b {Gz6u>  
;[RZ0Uy=  
lO2[JP  
public void run() ,lCgQ0}<  
{ 5U_H>oD  
//获得文件长度 5SkW-+$  
//分割文件 5>AX*]c  
//实例FileSplitterFetch }w4QP+ x  
//启动FileSplitterFetch线程 r-,e;o>9  
//等待子线程返回 gWY "w!f  
try{ 7)h[Zy,A  
if(bFirst) pLv$\ MiZ  
{ a<]B B$~  
nFileLength = getFileSize(); :$MG*/Q  
if(nFileLength == -1) *,BzcZ  
{ []s^   
System.err.println("File Length is not known!"); l }XU 59  
} Z$J#|  
else if(nFileLength == -2) vM_:&j_?``  
{ 0a"igq9t  
System.err.println("File is not access!"); xC C:BO`pw  
} u4Em%:Xj  
else <3,<\ub  
{ b,8{ X<  
for(int i=0;i<nStartPos.length;i++) 43V}# DA@  
{ VY)s+Bx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q\\gpCgp  
} vFEQ7 qI  
for(int i=0;i<nEndPos.length-1;i++) /  g 2b  
{ .jMq  
nEndPos = nStartPos[i+1]; A<;SnXm  
} %kgkXc~6|x  
nEndPos[nEndPos.length-1] = nFileLength; +**!@uY  
} .5  
} %,ngRYxT#  
B:7mpSnEQ  
BL&LeSa  
//启动子线程 ,]b~t0|B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h;3cd0  
for(int i=0;i<nStartPos.length;i++) 3j3N!T9  
{ Fv<`AU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vzmc}y G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x`6<m!d`  
nStartPos,nEndPos,i); ]vuwkn+)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _ 84ut  
fileSplitterFetch.start(); XV^1tX>f{  
} Ks}Xgc\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,-z9 #t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KF4PJi;*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^wS5>lf7p  
nEndPos = " + nFileLength); Is+O  
// fileSplitterFetch[nPos.length-1].start(); N!`e}Z6S  
0?>dCu\  
c&L"N!4z  
//等待子线程结束 `=7j$#6U  
//int count = 0; ;j2vHU#q-  
//是否结束while循环 Qyy.IPTP  
boolean breakWhile = false; kY'T{Sm1^  
]5%/3P,/  
}- Wa`t7U  
while(!bStop) "+unS)M;Y  
{ ;t+ub8  
write_nPos(); jbR0%X2  
Utility.sleep(500); '? jlH0;  
breakWhile = true; jMpD+Mb  
|.wEm;Bz  
H'HSD,>(  
for(int i=0;i<nStartPos.length;i++) `7H4Y&E  
{ ]n-:Yv5 W  
if(!fileSplitterFetch.bDownOver) VWO9=A*Y|  
{ o: ;"w"G  
breakWhile = false; ;,]P=Ey  
break; zz& ?{vJ  
} cYqfsd# B  
} ,*7d  
if(breakWhile) -ig6w.%lk  
break; _2N$LLbg  
D1 &A,2wO  
g(4xC7xK6  
//count++; 1T[et-  
//if(count>4) Y/7 $1k  
// siteStop(); H@l}WihW  
} gy nh#&r  
uIZWO.OdU  
!A%<#Gjt  
System.err.println("文件下载结束!"); rylzcN9RM$  
} ciMzf$+G$  
catch(Exception e){e.printStackTrace ();} K#"O a h  
} HF(KN{0.B  
zk( U8C+  
l<N}!lG|  
//获得文件长度 ."FuwKSJCo  
public long getFileSize() KIWe@e  
{ %dY<=x#b  
int nFileLength = -1; xNbPsoK  
try{ &iV,W4  
URL url = new URL(siteInfoBean.getSSiteURL()); o^ XtU5SVq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t]-5 ]oI  
httpConnection.setRequestProperty("User-Agent","NetFox"); [p<w._b i  
oJfr +3I  
F;]%V%F.X  
int responseCode=httpConnection.getResponseCode(); Phke`3tth  
if(responseCode>=400) @*sWu_ -Y%  
{ 4t)/  
processErrorCode(responseCode); AF%@VLf  
return -2; //-2 represent access is error GI&h`X5,e  
} e;(0(rI  
y99mC$"Ee`  
)P+7PhE{J  
String sHeader; !50[z:  
IC7M$  
[Vma^B$7Vj  
for(int i=1;;i++) qT^I?g"!  
{ Ng_!zrx04  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,2W8=ON  
//Utility.log(in.readLine()); /3{b%0Aa  
sHeader=httpConnection.getHeaderFieldKey(i); hvaSH69*m  
if(sHeader!=null) (P$H<FtH  
{ hodgDrmO/  
if(sHeader.equals("Content-Length")) &#iTQD  
{ B $mX3B+a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); eow'K 821A  
break; )vSRHE  
} 5D'\b}*lJ}  
} k`N^Vdr  
else 5s]. @C8  
break; >:b Q  
} aca=yDs2  
} yYfs y?3  
catch(IOException e){e.printStackTrace ();} zOiu5  
catch(Exception e){e.printStackTrace ();} :*KHx|Q  
_FWBUZ;N  
U-3i  
Utility.log(nFileLength); [)TRTxFb  
r! MWbFw|X  
ZEx}$<)_  
return nFileLength; Ll4g[8  
} <q@a~'Ai?!  
a8UwhjFO  
7K98#;a)5  
//保存下载信息(文件指针位置) :\o {_  
private void write_nPos() $\U 4hHOo  
{ c-0#w=  
try{ 55fC~J<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %B.yW`,X  
output.writeInt(nStartPos.length); HKUn`ng  
for(int i=0;i<nStartPos.length;i++) b"{'T]"*j  
{ (P:<t6;+  
// output.writeLong(nPos); AQwdw>I-FX  
output.writeLong(fileSplitterFetch.nStartPos); $F5 b  
output.writeLong(fileSplitterFetch.nEndPos); bXNk%W[n  
} ilqy /fL#  
output.close(); (:> ,u*x%  
} m*kl  
catch(IOException e){e.printStackTrace ();} |mw.qI|  
catch(Exception e){e.printStackTrace ();} FFEfI4&SfS  
} W*I(f]8:y`  
ZG&>:Si;  
71t* %  
//读取保存的下载信息(文件指针位置) lp^<3o*1  
private void read_nPos() u@cYw:-C  
{ =D<PVGo9  
try{ K42K!8$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mrF58Uq;A  
int nCount = input.readInt(); z+n,uHs  
nStartPos = new long[nCount]; ybKWOp:O  
nEndPos = new long[nCount]; "[ZB+-|[0  
for(int i=0;i<nStartPos.length;i++) LHo3 Niy.  
{ g0["^P1tV  
nStartPos = input.readLong(); d\gJ$ ~^K  
nEndPos = input.readLong(); 1 P!Yxeh  
} ~ r4 38&  
input.close(); rr02pM0  
} ElW~48  
catch(IOException e){e.printStackTrace ();} ,tu.2VQc@  
catch(Exception e){e.printStackTrace ();} |$ lM#Ua  
} #ZrHsf P  
HK0! P*  
Su/6Q$0 t  
private void processErrorCode(int nErrorCode) SSWP~ t  
{ LAS'u "c|  
System.err.println("Error Code : " + nErrorCode); IHv[v*4:  
} 9^#c| 0T  
E vg_q>  
2KYw}j|5  
//停止文件下载 sW'2+|3"  
public void siteStop() +Z !)^j  
{ ;"~ fZ2$U  
bStop = true; ]Hefm?9*^  
for(int i=0;i<nStartPos.length;i++)  :7]Sa`  
fileSplitterFetch.splitterStop(); ?WqT[MnK  
Ay0U=#XP  
WGZ9B^A  
} kr9*,E9cv  
} %|q>pin2  
//负责部分文件的抓取 3@$,s~+ 3  
**FileSplitterFetch.java  VoWNW  
*/ 67G?K;)e  
package NetFox; Zy?Hi`  
?En O"T.  
:fZ}o|t7  
import java.io.*; /YMj-S_b~  
import java.net.*; '6cWS'9"  
m4hg'<<V  
7>))D'l57  
public class FileSplitterFetch extends Thread { b)qoh^  
Ki$MpA3j   
|Sy<@oq  
String sURL; //File URL )I^7)x  
long nStartPos; //File Snippet Start Position SBfT20z[  
long nEndPos; //File Snippet End Position .yqM7U_  
int nThreadID; //Thread's ID f=r<nb'H  
boolean bDownOver = false; //Downing is over gv- xm  
boolean bStop = false; //Stop identical %4,O 2\0?&  
FileAccessI fileAccessI = null; //File Access interface _M`--.{\O[  
F`XP@Xx  
`tA" }1;ka  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "8x8UgG  
{ ~5%W:qwQ  
this.sURL = sURL; [ 0KlC1=  
this.nStartPos = nStart; xy/`ZS2WPq  
this.nEndPos = nEnd; "!ug_'VW  
nThreadID = id; [6%VRqY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %In A+5s`  
} c4^ks&)'  
|@ s,XS  
C.Kh [V\Ut  
public void run() BW}U%B^.  
{ qG?Qc (  
while(nStartPos < nEndPos && !bStop) !Sh&3uy_qN  
{ >,$_| C  
z"-u95H  
D%OQ e#!  
try{ r%yvOF\>  
URL url = new URL(sURL); /v1Q4mq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CY s,`  
httpConnection.setRequestProperty("User-Agent","NetFox"); fzb29 -  
String sProperty = "bytes="+nStartPos+"-"; 93("oBd[s(  
httpConnection.setRequestProperty("RANGE",sProperty); [65 `$x-  
Utility.log(sProperty); ~962i#&4  
QkEvw<  
`1$@|FgyC  
InputStream input = httpConnection.getInputStream(); mS$j?>m  
//logResponseHead(httpConnection); tl,.fjZn  
A@1W}8qY:  
bLij7K 2H  
byte[] b = new byte[1024]; Z<1FSk,[  
int nRead; "U>JM@0DNm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0WZ_7C?  
{ -Ta9 pxZk  
nStartPos += fileAccessI.write(b,0,nRead); Xqg@ e:g  
//if(nThreadID == 1) Ce9|=Jx!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "GMBjT8  
} P;=n9hgHI  
B}Z63|/N  
MDhRR*CBh  
Utility.log("Thread " + nThreadID + " is over!"); dMf:h"7  
bDownOver = true; 8<S~Z:JK  
//nPos = fileAccessI.write (b,0,nRead); ]@j*/IP  
} %Gz0^[+  
catch(Exception e){e.printStackTrace ();} )t0$qd ]  
} ZkRx1S"m  
} rzhWw-GY  
\o}xF@sM5  
z;{iM/Xe  
//打印回应的头信息 TN!j13,  
public void logResponseHead(HttpURLConnection con) U\4g#!qj  
{ M -cTRd-i  
for(int i=1;;i++) ww\CQ6/h  
{ l&OKBUG  
String header=con.getHeaderFieldKey(i); 2&:f&"  
if(header!=null) h)ECf?r<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QR c{vUR&  
Utility.log(header+" : "+con.getHeaderField(header)); =9y[1t  
else ?26I,:;  
break; A!s`[2 Z  
} Se :.4<  
} 2,$8icM  
Cc+t}"^  
l2zFKCGF(  
public void splitterStop() &gVN&  
{ we~[] \  
bStop = true; H*RC@O_hv  
} 0%9 q8 M;  
zT =Ho   
:~b3^xhc^  
} lGPUIoUo  
Bn=by{i  
.0S~872  
/* Uol|9F  
**FileAccess.java B:b5UD  
*//文件访问(定位,写) ZXqSH${Tp  
package NetFox; rn/ /%  
import java.io.*; <r .)hT"0  
bR*-Ht+wd  
*xx'@e|<;  
public class FileAccessI implements Serializable{ X[*<NN  
\f]k CB  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <C1H36p  
RandomAccessFile oSavedFile; C]O(T2l{l  
long nPos; RkH W   
oX#Q<2z*  
`slL %j^"  
public FileAccessI() throws IOException Yl4^AR&  
{ M>wYD\oeg  
this("",0); nOt&pq7  
} zvYq@Mhr  
yh Yb'GK  
MW! srTQ_  
public FileAccessI(String sName,long nPos) throws IOException 7L`A{L  
{ )IP,;<  
oSavedFile = new RandomAccessFile(sName,"rw"); 0[R L>;D:  
this.nPos = nPos; Ed0QQyC@9  
oSavedFile.seek(nPos); _(_a*ml  
} j@W.&- _  
**w!CaqvY  
(yu/l 6[  
public synchronized int write(byte[] b,int nStart,int nLen) ' KWyx  
{ ;+W# 5<i  
int n = -1; u!!Y=!y*<  
try{ H{@Yo\J  
oSavedFile.write(b,nStart,nLen); #o=y?(  
n = nLen; j#X.KM   
} s [M?as  
catch(IOException e) a=1NED'  
{ }\z.)B4,  
e.printStackTrace (); nGpXI\K  
} T}Km?d  
X\]L=>]C  
l Q'I  
return n; Pj#<K%Bz  
} Gy9$wH@8  
]mo-rhDsM  
eK6hS_E  
} Fz3fwLawI  
:Ux?,  
Qi ua  
/* sT !~J4  
**SiteInfoBean.java 3VsW@SG7N  
*/ WzPTFw[  
package NetFox; q 0$,*[PH  
2QD3&Q9  
9i'jj N  
public class SiteInfoBean { ; o?-yI&T*  
Q}1 R5@7  
[=E  
private String sSiteURL; //Site's URL &R[ M c-2  
private String sFilePath; //Saved File's Path *EOdEFsR/  
private String sFileName; //Saved File's Name ?^H `M|S  
private int nSplitter; //Count of Splited Downloading File _g+JA3sIJ  
-l`f)0{  
"oTHq]Ku  
public SiteInfoBean() WB?jRYp  
{//nSplitter的缺省值为5 Keuf9u  
//default value of nSplitter is 5 di?K"Z>  
this("","","",5); G^~k)6v=m  
} x^HGVWw_  
SFB~ ->db  
^"VJd[Hn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) W}3.E "K  
{ "8c@sHk(w  
sSiteURL= sURL; "w^!/  
sFilePath = sPath; xe#FUS 3  
sFileName = sName; yyoqX"v[  
this.nSplitter = nSpiltter; nc~F_i=  
GS0;bI4ay  
o}$XH,-9&  
} aK&b{d  
 W,4QzcQR  
'= _/1F*q  
public String getSSiteURL() NiWa7/Hr  
{ ;'?l$ ._  
return sSiteURL; G,$PV e*  
} ZO!I.  
Qt iDTr  
<A[E:*`*  
public void setSSiteURL(String value) R%Qf7Q  
{ :H7D~ n  
sSiteURL = value; "JVkVp[5D+  
} ]=.\-K  
?i)f^O  
l,R/Gl  
public String getSFilePath() 0)%YNaskj  
{ P<PJ)>  
return sFilePath; $$D}I*^Dt  
} E4gYemuN  
*-+&[P]m  
R? ,an2  
public void setSFilePath(String value) ~J5+i9T.)  
{ 1q~+E\x  
sFilePath = value; 0]>u )%  
} +!k&Yje  
O?NeSx 1  
S\''e`Eb"5  
public String getSFileName() 8MK>)P o)  
{ l\BVS)  
return sFileName; kQ4dwF~  
} +J_c'ChN  
AK&S5F>D+B  
&J55P]7w  
public void setSFileName(String value) b^ L \>3  
{ B||*.`3gN  
sFileName = value; $ .C=H[QC  
} :@kGAI  
{n(b{ ibl  
;6gDV`Twy  
public int getNSplitter() j Yx38_5e  
{ -#0qV:D  
return nSplitter; tna .52*/  
} ]p*l%(dhY  
V\6=ySx  
VOKZ dC-  
public void setNSplitter(int nCount) p%iGc<vHX  
{ 3Dg,GaRk  
nSplitter = nCount; r^h4z`:L  
} x N=i]~  
} ]Gpxhg  
Yb:\a/ y  
H70LhN  
/* 8j Mk)-  
**Utility.java H]Cy=Zi"  
*/ P6E3-?4j  
package NetFox; &/mA7Vf>eR  
nS/)P4z  
d1T,eJ}  
public class Utility { x HoKo  
W [Of|?  
1lq(PGX)  
public Utility() %F\?R[^5  
{ zBo1P(kek  
f _[<L  
q:l>O5  
} t/ +=|*  
-0?~  
//线程睡眠 7P" | J\  
public static void sleep(int nSecond) c#a @n 4  
{ M54j@_81pX  
try{ H:!7:  
Thread.sleep(nSecond); >G);j@Q  
} HuB<k3#sPy  
catch(Exception e) S7=Bd[4  
{ q+P|l5_ t  
e.printStackTrace (); aT_&x@x  
} >fe- d#!{  
} umD!2 w  
AP[|Ta  
//日志 6^uq?  
public static void log(String sMsg) T^:UBjK6t{  
{ &f!z1d-qg?  
System.err.println(sMsg); bx<RV7>0  
} '#s05hr  
0.dgoq 3u  
5:O-tgig.  
public static void log(int sMsg) }~#pEX~j*  
{ xB_!>SqF1U  
System.err.println(sMsg); W`K7 QWV4  
} ;epV<{e$q4  
} FQT~pfY  
dA@'b5N{"  
_Xnqb+  
/* Xg<*@4RD8  
**TestMethod.java Se HagKA  
*/ 9l}FU$  
package NetFox; t0z!DOODZP  
*_R]*o!W'  
[E+$?a=  
public class TestMethod { HHiT]S9  
XID<(HBA"!  
|3F02  
public TestMethod() A6GE,FhsG  
{ ///xx/weblogic60b2_win.exe cU ? 0(z7  
try{ M(jgd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GN-mrQo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wi[~fI8^!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "J+3w  
fileFetch.start(); ~2<7ZtV=  
} {S,l_d+(  
catch(Exception e){e.printStackTrace ();} 350_CN,  
u`y><w4i  
,stN  
} wSb 1"a  
3= xhoRX  
/V8}eZ97  
public static void main(String[] args) \zieyE  
{ 8#(Q_  
new TestMethod(); V+Cwzc^j  
} 7:9.&W/KE  
} L!=4N!j  
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