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http断点续传简单实现(java)

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/* m\/ Tj0e  
**SiteFileFetch.java \D>$aLO*?  
*/ MxzLK%am  
package NetFox; Knhp*V?  
import java.io.*; ?^:h\C^a"  
import java.net.*; &D%(~|'  
0J.dG/I%  
&rDM<pO #-  
public class SiteFileFetch extends Thread { :b[`  v  
H A}f,),G  
,3I^?5  
SiteInfoBean siteInfoBean = null; //文件信息Bean pf4 ^Bk}e  
long[] nStartPos; //开始位置 oJKa"H-jL  
long[] nEndPos; //结束位置 Vtppuu$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >=iy2~Fz,  
long nFileLength; //文件长度 4'KOp&#l K  
boolean bFirst = true; //是否第一次取文件 v){ .Z^_C  
boolean bStop = false; //停止标志 jkiTj~WE-  
File tmpFile; //文件下载的临时信息 RFh"&0[  
DataOutputStream output; //输出到文件的输出流 rQTr8DYH  
/yLZ/<WN  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \, !Q Jp4  
public SiteFileFetch(SiteInfoBean bean) throws IOException \.XLcz  
{ 2cu#lMq  
siteInfoBean = bean; 8 i&_Jgmr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +l^LlqA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >r &;3:"  
if(tmpFile.exists ()) 9;yn}\N `  
{ 6io, uh!  
bFirst = false; UZ8?[  
read_nPos(); nS()u}c;r  
} U $Qv>7  
else zF4[}*  
{ ,fEO> i  
nStartPos = new long[bean.getNSplitter()]; Z -%(~  
nEndPos = new long[bean.getNSplitter()]; wOB azWa   
} LtT\z<bAI  
(I@bkMp  
E^w:KC2@  
ZxGP/D  
} 2/,0iwj-  
j QU"Ved  
iAY!oZR(WT  
public void run() {f9{8-W <u  
{ 0oy-os  
//获得文件长度 jClj_E  
//分割文件 ]0D}T'wM  
//实例FileSplitterFetch [6jbgW~E  
//启动FileSplitterFetch线程 ThW,Y" l  
//等待子线程返回 @1zQce>  
try{ K}[>T(0E  
if(bFirst) cYNJhGY  
{ ,? E&V_5  
nFileLength = getFileSize(); 9>/wUQs!]  
if(nFileLength == -1) HG/p$L*  
{ =TR,~8Z|  
System.err.println("File Length is not known!"); Gf8s?l  
} G ;?qWB,  
else if(nFileLength == -2)  Lw1T 4n  
{ l0*Gb  
System.err.println("File is not access!"); 3CTX -#)vS  
} 4eVI},  
else (3\Xy   
{ r!}al5~&  
for(int i=0;i<nStartPos.length;i++) Dc~,D1xWj  
{ H* !EP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %/kyT%1  
} ]IJRnVp%  
for(int i=0;i<nEndPos.length-1;i++) ^"8G`B$r  
{ 9Qj2W  
nEndPos = nStartPos[i+1]; {#IPf0O  
} {|9}+ @5Q1  
nEndPos[nEndPos.length-1] = nFileLength; 4t4olkK3Oa  
} QD{:vG g  
} `h;k2Se5  
9^P2I)aD  
! BU)K'mj  
//启动子线程 Kex[ >L10G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0ZAj=u@O  
for(int i=0;i<nStartPos.length;i++) l2b{u GE  
{ 0f ER*.F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F{k+7Ftc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1|,Pq9  
nStartPos,nEndPos,i); gG54:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N132sN2   
fileSplitterFetch.start(); fYebB7Pv  
} WUAJjds  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fbZibcQ%k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OH<?DcfeL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T0j2a &Pv  
nEndPos = " + nFileLength); 3L-^<'~-k;  
// fileSplitterFetch[nPos.length-1].start(); jW*1E *"  
:ZdUx  
~Pk0u{,4XQ  
//等待子线程结束 %R_{1GrL'c  
//int count = 0; m$>iS@R  
//是否结束while循环 =fc: 6JR  
boolean breakWhile = false; ,KW;2t*IQ@  
:lcea6iO  
9T2xU3UyY  
while(!bStop) /I&wj^   
{ #nyv+x;  
write_nPos(); j{#Wn !,  
Utility.sleep(500); 'p)Q68;&  
breakWhile = true; =4C}{IL  
"YFls#4H-  
h?@G$%2  
for(int i=0;i<nStartPos.length;i++) ;mm!0]V  
{ &!7+Yb(1  
if(!fileSplitterFetch.bDownOver) ic6L9>[  
{ Y5A~E#zw  
breakWhile = false; h~HB0^|  
break;  ~QG ?k  
} f F?6j   
} >AD =31lq  
if(breakWhile) #?} 6t~  
break; 1`r| op},  
&j u-  
.I?@o8'x  
//count++; c $;\i  
//if(count>4) upn8n vy4(  
// siteStop(); 8 ?TKN~ja  
} lpQP"%q  
TZ^LA L'8_  
a,'Cyv">  
System.err.println("文件下载结束!"); <2Y0{ 8)  
} 6=|&tE  
catch(Exception e){e.printStackTrace ();} t\U$8l_;  
} 2iXoj&3e  
#Olg(:\  
<SXZx9A!  
//获得文件长度 ?z`MPdO  
public long getFileSize() vM0_>1nN  
{ ,^T]UHRO  
int nFileLength = -1; %j]ST D.E  
try{ ,j9 80/  
URL url = new URL(siteInfoBean.getSSiteURL()); )@QJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "mj^+u-  
httpConnection.setRequestProperty("User-Agent","NetFox"); m$UvFP1>u1  
Y'm=etE  
H~+xB1  
int responseCode=httpConnection.getResponseCode(); i1*C{Lf;%)  
if(responseCode>=400) vx0UoKX  
{ ]Bu DaxWN  
processErrorCode(responseCode); %&] 1FhL  
return -2; //-2 represent access is error p]LnE `v  
} 7s>a2  
r7z6___  
?A=b6Um  
String sHeader; 4^Qi2[w  
Z}Cqd?_')  
TnxKR$Hoh  
for(int i=1;;i++) ~@c-*  
{ g,lY ut  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  0%Q9}l#7  
//Utility.log(in.readLine()); hYt7kq!"  
sHeader=httpConnection.getHeaderFieldKey(i); >S&U.  
if(sHeader!=null) 4 \Di,PPu  
{ ?9?4p@  
if(sHeader.equals("Content-Length")) e9@(/+  
{ ]S /G\z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tW6#e(^l6  
break; }OKL z.5  
} XCPb9<L  
} ]mkJw3  
else `"<2)yq?  
break; p]f&mBO*  
} $4j^1U`~)K  
} )h"Fla  
catch(IOException e){e.printStackTrace ();} +^Jwo)R'b  
catch(Exception e){e.printStackTrace ();} Xz1c6mX|o  
mUwUs~PjA  
yjZ2 if  
Utility.log(nFileLength); D$pj#  
wa?+qiWnrl  
b~w KF0vq  
return nFileLength; 'C]jwxy  
} H`|0-`q  
K+ehr  
Cg6;I.K   
//保存下载信息(文件指针位置) V9jFjc?  
private void write_nPos() : ^(nj7D  
{ *FPg#a+  
try{ Z`xyb>$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gduxA/aT  
output.writeInt(nStartPos.length); Q_lu`F|  
for(int i=0;i<nStartPos.length;i++) EVz9WY  
{ p$OD*f_b  
// output.writeLong(nPos); 9eSRCLhgD  
output.writeLong(fileSplitterFetch.nStartPos); /RF%1!M K  
output.writeLong(fileSplitterFetch.nEndPos); rgR?wXW]jE  
} el Kx]%k*)  
output.close(); g~R/3cm4  
} Uz>Yn&{y6  
catch(IOException e){e.printStackTrace ();} 2]Fu 1  
catch(Exception e){e.printStackTrace ();} 6Kht:WE  
} hmzair3X  
-Op@y2+c  
c,BAa*]K  
//读取保存的下载信息(文件指针位置) j;0ih_Z@4W  
private void read_nPos() iPFL"v<#J  
{ !$E~\uT  
try{ wO.B~`y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mVrKz  
int nCount = input.readInt(); \9jpCNdJ  
nStartPos = new long[nCount]; 32KR--mn%  
nEndPos = new long[nCount]; 9S"N4c>  
for(int i=0;i<nStartPos.length;i++) .HDebi  
{ "o==4?*L  
nStartPos = input.readLong(); d<Dn9,G  
nEndPos = input.readLong(); L w*1 .~  
} {{zua- F  
input.close(); BD4"pcr  
} /$*; >4=>f  
catch(IOException e){e.printStackTrace ();} 0~i qG  
catch(Exception e){e.printStackTrace ();} TQ~&Y)".  
} W9jNUZVXE#  
:~r#LRgc  
=F[lg?g  
private void processErrorCode(int nErrorCode) Nh :JU?h  
{ JJNmpUJ  
System.err.println("Error Code : " + nErrorCode); 5=.7\#D  
} ahoh9iJ  
cUV TRWV  
Zih5/I  
//停止文件下载 "o<D;lO  
public void siteStop() _DrnL}9I7  
{ y3AL)  
bStop = true; :+1bg&wQ  
for(int i=0;i<nStartPos.length;i++) JOgmF_(>Z  
fileSplitterFetch.splitterStop(); f-s~Q 4  
kI]=&Rw  
{ "}+V`O{  
} s #`cX0L)  
} ;$[VX/A`f  
//负责部分文件的抓取 QS%,7'EG  
**FileSplitterFetch.java wK ][qZ ]  
*/ =%)})  
package NetFox; @|]iSD&T #  
gpsrw>nw  
B~4mk  
import java.io.*; ~q5-9{ma  
import java.net.*; 2}|vWKej{  
k$?&]! <o  
!yk7HaP  
public class FileSplitterFetch extends Thread { X`tOO  
>]C<j4  
/o'oF  
String sURL; //File URL M+\rX1T  
long nStartPos; //File Snippet Start Position >pa\n9=Q^  
long nEndPos; //File Snippet End Position =Y:5,.U  
int nThreadID; //Thread's ID zH'!fhcy  
boolean bDownOver = false; //Downing is over .0KOnLdK  
boolean bStop = false; //Stop identical I(y`)$}  
FileAccessI fileAccessI = null; //File Access interface 0A@-9w=u  
krwf8!bI  
)*+u\x_Hx  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0rGj|@+;  
{ yCZ2^P!a  
this.sURL = sURL; ]~ >@%v&  
this.nStartPos = nStart; l`oT:  
this.nEndPos = nEnd; QM7[O]@  
nThreadID = id; A>[hC{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H2s*s[T -  
} $kM '  
w# xncH:1  
X #H:&*[!  
public void run() J~fuW?a]r  
{ 5=Zp%[ #  
while(nStartPos < nEndPos && !bStop) L>i<dD{  
{ -.^=Z!=M  
ho(5r5SNE  
6{lG1\o  
try{ '=-s1c@^  
URL url = new URL(sURL); ;c nnqT6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,q/tyGj  
httpConnection.setRequestProperty("User-Agent","NetFox"); \;'_|bu3.  
String sProperty = "bytes="+nStartPos+"-"; ;}$Z 80  
httpConnection.setRequestProperty("RANGE",sProperty); VoWA tNU  
Utility.log(sProperty); m]Hb+Y=;h  
Hs.6;|0%  
r=xTs,xx  
InputStream input = httpConnection.getInputStream(); ZKZl>dDuh  
//logResponseHead(httpConnection); |2[S/8g!  
)Fw @afE~  
AfuXu@UZ_/  
byte[] b = new byte[1024]; nmTm(?yE  
int nRead; zK[ 7:<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5/zf x  
{ Cca~Cq[%*(  
nStartPos += fileAccessI.write(b,0,nRead); ;*n_N!v  
//if(nThreadID == 1) pE~9o 9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [BJ$|[11  
} rDK;6H:u{  
Qo]vpp^[#  
X v`2hf  
Utility.log("Thread " + nThreadID + " is over!"); z +y;y&P  
bDownOver = true; BLWA!-  
//nPos = fileAccessI.write (b,0,nRead); |Gf1^8:C9  
} s@.`"TF.7  
catch(Exception e){e.printStackTrace ();} UZ[/aq  
} "u .)X3  
} yBJ/>SAcG  
w++B-_  
pjaiAe!k  
//打印回应的头信息 :<'i-Ur8  
public void logResponseHead(HttpURLConnection con) A73V6"  
{ GMVC&^  
for(int i=1;;i++) h[Ndtq>3{  
{ 2V#c[%vI  
String header=con.getHeaderFieldKey(i); d08`42Z69  
if(header!=null) T b5$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r\4*\  
Utility.log(header+" : "+con.getHeaderField(header)); OL,/-;z6  
else !C9ps]6  
break; hr )+Pk  
} @&!=m]D*  
} U)O?| VN^o  
Gp?ToS2^d  
Z%,\+tRe  
public void splitterStop() 6\NX 5Gh  
{ JL}hOBqfI  
bStop = true; {mCKTyN+  
} +#de8/x  
8MYLXW6  
zgEr,nF  
} vkDZv@  
3I(dC|d  
<M5{.`o  
/* jsZiARTZRl  
**FileAccess.java /Bg6z m  
*//文件访问(定位,写) l(3'Re  
package NetFox; se^NQ=  
import java.io.*; 2)HxW}o  
1NE!=;VOl  
,v$2'm)V  
public class FileAccessI implements Serializable{ ~#HH;q_7m  
GFASF,+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X+?Il)Bv  
RandomAccessFile oSavedFile; knNhN=hG+  
long nPos; T:w2  
L@gQ L  
35]j;8N:  
public FileAccessI() throws IOException 2XETQ;9  
{ Mhu53DT  
this("",0); P%<aGb4  
} m<X#W W)N  
\Y>#^b?  
)V9Mcr*Ce6  
public FileAccessI(String sName,long nPos) throws IOException l`~a}y"n  
{ Z>>gXh<e[  
oSavedFile = new RandomAccessFile(sName,"rw"); 8|S1|t,  
this.nPos = nPos; ! 4qps$p{  
oSavedFile.seek(nPos); p[af[!  
} :>AW@SoTp  
qb>|n1F_  
rE bx%u7Q  
public synchronized int write(byte[] b,int nStart,int nLen) h;4y=UU  
{ P!)7\.7  
int n = -1; R"9oMaY  
try{ 'NG^HLD/  
oSavedFile.write(b,nStart,nLen); (7rz:  
n = nLen; `[C  v-  
} Q*mMF@-:  
catch(IOException e) A|`Joxr  
{ ~_f |".T  
e.printStackTrace (); +7lRP)1R  
} Xj})?{FP  
x 1%J1?Fp  
>tXufzW  
return n; &dwI8@&  
} ~q'w),bE"Q  
Sug~FV?k$e  
8zWBXV  
} ?C#F?N0  
cW~6@&zp  
]$?zT`>(F  
/* ( TbB?X}  
**SiteInfoBean.java ||*&g2Y  
*/ A^= Hu,"e  
package NetFox; U:pLnNp`  
Vx\# +)4  
C,VqT6E<  
public class SiteInfoBean { O_ s9  
b Q9"GO<X  
Us@ {w`T  
private String sSiteURL; //Site's URL [X$|dOm'N  
private String sFilePath; //Saved File's Path 1=/MT#d^?  
private String sFileName; //Saved File's Name 5w,YBUp  
private int nSplitter; //Count of Splited Downloading File vBCZ/F[  
[# tT o;q  
pT_e;,KW U  
public SiteInfoBean() :(S/$^U  
{//nSplitter的缺省值为5 RB$ 8^#  
//default value of nSplitter is 5 L[QI 5N  
this("","","",5); "PDSqYA  
} +n8I(l=  
9rf|r 3  
)@lo ';\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]'  "^M  
{ 8^~ZNU-~v  
sSiteURL= sURL; kw-Kx4 )  
sFilePath = sPath; ]~g|SqPA@  
sFileName = sName; F|n$0vQ*  
this.nSplitter = nSpiltter; 9bzYADLI  
YiI:uG!|D  
O+8ApicjTc  
} P7BJ?x  
z*k 3q`=>  
Ie`SWg*WL  
public String getSSiteURL() &:cTo(C'  
{ d)17r\*>I  
return sSiteURL; 5f^`4 pT  
} >{LJ#Dc6  
m|?" k38  
5@%=LPV  
public void setSSiteURL(String value) 4~pO>6P   
{ ?GMeA}j  
sSiteURL = value; $Zu4tuXA  
} 7PQj7&m  
g)r ,q&*  
)/N Xh'  
public String getSFilePath() onJ[&f  
{ M'!!EQo  
return sFilePath; hc p'+:  
} sVm'9k  
;uWI l  
<x%my4M  
public void setSFilePath(String value) loqS?bC ]  
{ -WHwz m  
sFilePath = value; \<MTY:  
} a\.OL}"   
8`LLHX1|  
Dk{nOvZu<  
public String getSFileName() "6 Hj ji@A  
{ m%$E[cUW!  
return sFileName; .n|3A3:  
} [F>n!`8  
:+Je989\[C  
.D2ub/er  
public void setSFileName(String value) Z5^,!6  
{  V\7u  
sFileName = value; bM3'm$34  
} 2Nt]Nj`  
*}WqYqOow  
7zk m  
public int getNSplitter() K?9H.#(  
{ $m%/veD k  
return nSplitter; AdN= y8T  
} B8#f^}8  
7_'k`J@_  
DkMC!Q\  
public void setNSplitter(int nCount) @SVEhk#  
{ GPhwq n{  
nSplitter = nCount; fS$Yl~-m?  
} $;`2^L  
} U-^S<H  
P@T $6%~  
1.OXkgh  
/* Y<$"]@w  
**Utility.java zZ"')+7q&%  
*/ wCEfR!i  
package NetFox; N@`9 ~JS  
v_ F?x!  
{~p %\  
public class Utility { x?k |i}Q  
bA9dbe  
w!Lb;4x ?  
public Utility() nOoh2jUM  
{ E=U^T/  
V@s/]|rf,  
gdn,nL`dP  
} !Q/O[6  
PL B=%[  
//线程睡眠 ++RmaZ  
public static void sleep(int nSecond) sVl:EVv  
{ 'A@Oia1;{  
try{ C g,w6<7  
Thread.sleep(nSecond); o>k-~v7  
}  u^eC  
catch(Exception e) _"e( ^yiK  
{ E ^>7jf09,  
e.printStackTrace (); r3lr`s`  
} #S74C*'8  
} 2OOj8JS  
eMMiSO!3  
//日志 VQJ5$4a&  
public static void log(String sMsg) mp$II?hZ*  
{ Rn ^N+3o'M  
System.err.println(sMsg); Mh B=+S[@  
} t $ ~:C  
;."{0gq  
f2K3*}P  
public static void log(int sMsg) $fpDABf  
{ "Q!{8 9Y  
System.err.println(sMsg); +?eAaC7s  
} j W]c9u  
} 9Yne=R/]  
/u1zRw  
GnHf9 JrR  
/* W${sD|d-  
**TestMethod.java wx7>0[zE  
*/ <5L`d}  
package NetFox; @)B5^[4(;  
^rb7`s#G  
0 #; s{7k  
public class TestMethod { d~s-;T  
\e vgDZf  
uPD_s[  
public TestMethod() \nt'I;f  
{ ///xx/weblogic60b2_win.exe -P uVI5L<  
try{ Ho{?m^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lt2& uYgp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^g"6p#S=n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?O]gFn  
fileFetch.start(); NY w(hAPv  
} 78A4n C  
catch(Exception e){e.printStackTrace ();} $w}aX0dK&  
% ieAY-<"  
m`6`a|Twp$  
} 5w%9b  
V^H47O;VC  
9GOyVKUv  
public static void main(String[] args) 3Jit2W4  
{ Xq$0% WjG  
new TestMethod(); c=mFYsSv  
} 4h@of'  
} g5]DA.&(  
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