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http断点续传简单实现(java)

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/* D6"d\F m<  
**SiteFileFetch.java >&k`NXS|V  
*/ B79~-,Yh  
package NetFox; KXpbee  
import java.io.*; YLS*uXB&.  
import java.net.*; $My~sN8  
t*dq*(3"c  
PS=q):R|  
public class SiteFileFetch extends Thread { rQJ\Y3.  
f0R+Mz8{  
r'lANl-v  
SiteInfoBean siteInfoBean = null; //文件信息Bean S <-5<Pg  
long[] nStartPos; //开始位置 9}L2$^#,NA  
long[] nEndPos; //结束位置 3}fhU{-c  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G}LV"0?  
long nFileLength; //文件长度 Z@%A(nZ_  
boolean bFirst = true; //是否第一次取文件 1=C<aRZ b^  
boolean bStop = false; //停止标志 b`% !\I  
File tmpFile; //文件下载的临时信息 O1wo KkfV  
DataOutputStream output; //输出到文件的输出流 k+J63+obd  
Z9*@w`x^u  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) UJ(UzKq8  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z[B:6\oQ  
{ E|jU8qz>P  
siteInfoBean = bean; l2YA/9.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g_A#WQyh\'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7%[ YX  
if(tmpFile.exists ()) |.$7.8g  
{ .}uri1k"@k  
bFirst = false; Y9&na&vY?  
read_nPos(); x34GRe!!  
} fVVD}GM=  
else P,xJVo\  
{ d0&  
nStartPos = new long[bean.getNSplitter()]; mahNQ5W*)  
nEndPos = new long[bean.getNSplitter()]; =+I-9=  
} ,}"jiGgS4  
@ &Od1X  
2@@evQ  
ZLdIEBi=  
} uu"hu||0_  
k@h0 }%  
8R-;cBT  
public void run() 5uOz#hN  
{ mdo$d-d&  
//获得文件长度 O{Mn\M6  
//分割文件 :z *jl'L  
//实例FileSplitterFetch x9S9%JG :  
//启动FileSplitterFetch线程 z#rp8-HUDS  
//等待子线程返回 ;>;it5 l=  
try{ 2-W y@\  
if(bFirst) 1L!jI2~x}  
{ `e?~c'a@  
nFileLength = getFileSize(); *"4l}&  
if(nFileLength == -1) pU[yr'D.r  
{ y$_]}<b  
System.err.println("File Length is not known!"); ,nGQVb   
} TtKKU4yp  
else if(nFileLength == -2) rkR~%U6V  
{ 5tzO=gO[  
System.err.println("File is not access!"); <`NsX 6t  
} {,Rlq  
else JAI.NKB3  
{ 25j\p{*  
for(int i=0;i<nStartPos.length;i++) B@VAXmCaoV  
{ 6`bR' 0D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]*Q,~uV^|  
} <P6d-+  
for(int i=0;i<nEndPos.length-1;i++) H* +7{;$  
{ VZ y$0*  
nEndPos = nStartPos[i+1]; {^^LeUd#V  
} yy&L&v'  
nEndPos[nEndPos.length-1] = nFileLength; K5\l (BB  
} ^U96p0H"T  
} I0=L_&`)  
oA7|s1  
N 7Y X  
//启动子线程  Zy8tI#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U~t!   
for(int i=0;i<nStartPos.length;i++) ]VE3u_kR  
{ 53pT{2]zAi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s.n:;8RibP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qDz[=6BF  
nStartPos,nEndPos,i); x; -D}#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }UQ,B  
fileSplitterFetch.start(); @LDs$"f9=  
} j]]5&u/l  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qDhZC*"9#D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X8?@Y@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AZA5>Y  
nEndPos = " + nFileLength); @$ lX%p>  
// fileSplitterFetch[nPos.length-1].start(); Z,81L3#6  
:XPat9 3w  
:nc%:z=O  
//等待子线程结束 /=A@O !l  
//int count = 0; rmtCCPF?0  
//是否结束while循环 2V u?Y  
boolean breakWhile = false; 9 `q(_\x  
m\bmBK"I  
 H{Lt,#  
while(!bStop) RAws{<6T-  
{ }[MkJ21!  
write_nPos(); csxn" Dz\  
Utility.sleep(500); -S&9"=v  
breakWhile = true; a1u4v/Qu9  
[z+YX s!N  
^tWSu?9  
for(int i=0;i<nStartPos.length;i++) wL^x9O|`p9  
{ ; C(5lD&\5  
if(!fileSplitterFetch.bDownOver) bn5O2  
{ qt/6o|V  
breakWhile = false; @ 'N $5  
break; rOO10g  
} 'zT7$ .L  
} a|#pl!  
if(breakWhile) &0:Gj3`  
break; M"u=)CT  
\u(Gj]B#"  
:(tKc3z  
//count++; dLwP7#r  
//if(count>4) 8*&73cp  
// siteStop(); Gm=&[?}  
} l @@pXg3  
Qz%q#4Zb  
Zr A*MN  
System.err.println("文件下载结束!"); kM=&Tfpj  
} h4MBw=Tz~  
catch(Exception e){e.printStackTrace ();} 0Js5 ' 9}H  
} rg]b$tL~  
@\xEK5SG  
}1+2&Ps50  
//获得文件长度 5J&Gc;  
public long getFileSize() _5O~ ]}  
{ % W|Sl  
int nFileLength = -1; :?m"kh ~  
try{ C=U4z|Ym  
URL url = new URL(siteInfoBean.getSSiteURL()); 9f5~hBlo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1&7?f  
httpConnection.setRequestProperty("User-Agent","NetFox"); O:RN4/17  
) =x4+)9  
589fr"Ma,6  
int responseCode=httpConnection.getResponseCode(); j \d)#+;  
if(responseCode>=400) M(C}2.20  
{ )`\Q/TMl5  
processErrorCode(responseCode); j]5e$e{  
return -2; //-2 represent access is error 7Q~W}`Qv'  
} 0/fZDQH  
v$(Z}Hg  
{TMng&  
String sHeader; qs_cC3"=%=  
uGW#z_{(n  
B> \q!dX3  
for(int i=1;;i++) 0oBAJP  
{ F{.g05^y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6cbV[ !BL  
//Utility.log(in.readLine()); NiE`u m  
sHeader=httpConnection.getHeaderFieldKey(i); ]gv3|W  
if(sHeader!=null) O*,O]Q  
{ KZ^>_K&  
if(sHeader.equals("Content-Length")) wc"~8Ah  
{ }j2t8B^&:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '.S02=/  
break; {Dy,|}7s  
} Az#kE.8b*A  
} .W2w/RayC  
else \ :q@I]2  
break; QyZ' %T5J  
} XH/!A`ZK  
} D@[#7:rHL  
catch(IOException e){e.printStackTrace ();} -HuIz6  
catch(Exception e){e.printStackTrace ();} HJpx,NU'  
?6x&A t  
yGC HWP  
Utility.log(nFileLength); }NdLd!  
!,5qAGi0  
DZb0'+jQ  
return nFileLength; *H=h7ESq  
} T%Zfo7  
JnnxXj30,  
yOb']  
//保存下载信息(文件指针位置) U-f8 D  
private void write_nPos() ?>vkY^/  
{ {BaPK&x,  
try{ ;<E?NBV^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]rg-=Y k  
output.writeInt(nStartPos.length); ymqn1ja1  
for(int i=0;i<nStartPos.length;i++) n: {f\  
{ <4/q5*&  
// output.writeLong(nPos); |q\i, }  
output.writeLong(fileSplitterFetch.nStartPos); F* Yx1vj  
output.writeLong(fileSplitterFetch.nEndPos); s+G( N$0U  
} {`J!DFfur  
output.close(); (r}StR+  
} $`t2SD  
catch(IOException e){e.printStackTrace ();} +#(GU9_i+M  
catch(Exception e){e.printStackTrace ();} ?@Tsd@s~r  
} Yc3\  
o@aXzF2  
_ |HA\!  
//读取保存的下载信息(文件指针位置) $`0,N_C<}  
private void read_nPos() M;KeY[u  
{ =>A}eR1Y   
try{ BZXee>3"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t 0p  
int nCount = input.readInt(); '9<8<d7?  
nStartPos = new long[nCount]; r4K%dx-t  
nEndPos = new long[nCount]; HyYJ"54  
for(int i=0;i<nStartPos.length;i++) ,5 3`t  
{ j0 Os]a  
nStartPos = input.readLong(); ]lE5^<<  
nEndPos = input.readLong(); aSHN*tP%y  
} uz=9L<$  
input.close(); HoWK# Nz\  
} 6ZjY-)h  
catch(IOException e){e.printStackTrace ();} I,& gKgh  
catch(Exception e){e.printStackTrace ();} Jiru~Vo+  
} HFz;"s3lWM  
BI!EmA  
H,j_2JOY=  
private void processErrorCode(int nErrorCode) ]f wW dtz1  
{ qk0cf~ gz  
System.err.println("Error Code : " + nErrorCode); c@4$)68  
} 7W&XcF  
)RWukr+  
UKB/>:R  
//停止文件下载 +9<:z\B|  
public void siteStop() Hf30ve}  
{ uo|:n"v  
bStop = true; RgM=g8}M  
for(int i=0;i<nStartPos.length;i++) ~rAcT6#  
fileSplitterFetch.splitterStop(); V^}$f3\B  
 Sb)}  
 5pHv5e  
} ;LKYA?=/V  
} Y2g%{keo  
//负责部分文件的抓取 QNXS.!\P  
**FileSplitterFetch.java W3%RB[s-  
*/ ,&Zk63V  
package NetFox; U2Ky4UFm  
%y)hYLOJ  
>f|0# *  
import java.io.*; {5+69&:G.  
import java.net.*; O%&N6U  
UCTc$3  
1$m{)Io2(  
public class FileSplitterFetch extends Thread { 7 VYhRC-  
UvqnNA  
,t'"3<^Jg  
String sURL; //File URL 6_tl_O7  
long nStartPos; //File Snippet Start Position F2)KAIl  
long nEndPos; //File Snippet End Position qB`%+<)C  
int nThreadID; //Thread's ID -|=)  
boolean bDownOver = false; //Downing is over -`t9@1P> =  
boolean bStop = false; //Stop identical sdgI ,  
FileAccessI fileAccessI = null; //File Access interface Az>r}*F Gr  
`P*wZKlW  
,. <c|5R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BcQw-<veu  
{ X%7l! k[  
this.sURL = sURL; RYl\Q,#  
this.nStartPos = nStart; `\=~ $&vjC  
this.nEndPos = nEnd; ~!%G2E!  
nThreadID = id; s]D1s%Mx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k6\&[BQs  
} Ms+SJ5Lg  
!rG-[7K  
_,p/2m-Pj  
public void run() 3 rLc\rK  
{ N5xI;UV9'  
while(nStartPos < nEndPos && !bStop) dLR[<@E  
{ FL0yRF5  
XuU>.T$]c  
xa{.hp?  
try{ lhBAT%U\  
URL url = new URL(sURL); J10&iCr{r*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iqsR]mab  
httpConnection.setRequestProperty("User-Agent","NetFox"); W3R43>$  
String sProperty = "bytes="+nStartPos+"-"; nwDGzC~y<  
httpConnection.setRequestProperty("RANGE",sProperty); $)=`Iai  
Utility.log(sProperty); C]na4yE 8  
H87k1^}HV  
!D/W6Ic@  
InputStream input = httpConnection.getInputStream(); v|3mbApv  
//logResponseHead(httpConnection); C9>^!?>  
!!~r1)zN  
G=kW4rAk  
byte[] b = new byte[1024]; N Zwi3  
int nRead; Ov.oyke4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J*^ i=y  
{ D8$4PT0u  
nStartPos += fileAccessI.write(b,0,nRead); .9<euPrz  
//if(nThreadID == 1) d zV2;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @%^h|g8>Fu  
} "|PX5  
~C?)- ]bF  
KHeeB`V>J  
Utility.log("Thread " + nThreadID + " is over!"); 7!6v4ZA  
bDownOver = true; y+Bxe )6^V  
//nPos = fileAccessI.write (b,0,nRead); )cm^;(#pV  
} )R"UX:Q>  
catch(Exception e){e.printStackTrace ();} zzT4+wy`  
} ,V;HM F.  
} bGlr>@;-r  
(!Fu5m=<8  
LftGA7uGJ)  
//打印回应的头信息 zq|NltK  
public void logResponseHead(HttpURLConnection con)  ]l  
{ SUsdX[byb  
for(int i=1;;i++) _0Y?(}  
{ #aKUD  
String header=con.getHeaderFieldKey(i); JPg^h  
if(header!=null) \e%%ik,<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _) UnHp_^  
Utility.log(header+" : "+con.getHeaderField(header)); un)PW&~E  
else UGoB7TEfn  
break; h6;zAM}  
} W"tGCnd  
} #smfOGSd  
58o&Dv6?  
|HwEwL+  
public void splitterStop() Xl>ZnI];  
{ -L wz T  
bStop = true; w@a|_?  
} ')(U<5y)  
: TqeVf  
X*&Thmee  
} 9]I{GyH  
mCQ:< #  
~/2OK!M  
/* B}N1}i+  
**FileAccess.java r( zn1;zl  
*//文件访问(定位,写) t&_X{!1X"w  
package NetFox; &(|x-OT  
import java.io.*; G P`sOPr  
Ejyo oO45  
/2 $d'e  
public class FileAccessI implements Serializable{ vxrqUjK7  
Mh}vr%0;)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _93:_L  
RandomAccessFile oSavedFile; `9acR>00$  
long nPos; <2O XXQ1  
o ethO  
RE08\gNIt  
public FileAccessI() throws IOException dl3}\o_  
{ :_o^oi7G  
this("",0); oZi{v]4  
} U/h@Q\~U  
STPRC&7;  
*lQa^F  
public FileAccessI(String sName,long nPos) throws IOException CKC5S^Mx  
{ A5sz[k  
oSavedFile = new RandomAccessFile(sName,"rw"); J58S8:c  
this.nPos = nPos; +HG*T[%/  
oSavedFile.seek(nPos); P4 #j;k4P  
} KD- -w(4  
`A8ErfA  
sR)jZpmC(  
public synchronized int write(byte[] b,int nStart,int nLen) 9d!mGnl  
{ nt%p@e!,  
int n = -1; Hv%$6,/*v  
try{ V$dhiP z  
oSavedFile.write(b,nStart,nLen); BW"24JhF"  
n = nLen; pfFHuS~  
} |ZOdfr4uW  
catch(IOException e) 9xFI%UOb#  
{ t~8H~%T>v  
e.printStackTrace (); vD(:?M  
} + 7wMM#z  
p+b$jKWQ  
Hk=HO|&<XB  
return n; *<X*)A{C  
} |n~,{=  
Mu6DT p~k  
-]QP#_   
} er3`ITp:dp  
<*o V-A  
'c3'eJ0  
/* B|'}HBkP  
**SiteInfoBean.java Tf('iZ2+  
*/ wNmC1HOh  
package NetFox; T>J ,kh  
#G=AD/z  
eL{$=Um  
public class SiteInfoBean { DD`DU^o<  
FwD q@Oj  
^$[iLX  
private String sSiteURL; //Site's URL YWL7.Y>%5  
private String sFilePath; //Saved File's Path 8i)9ho<  
private String sFileName; //Saved File's Name z|\n^ZK=  
private int nSplitter; //Count of Splited Downloading File #er% q:  
^1_CS*  
"akAGa!V+  
public SiteInfoBean() Zx7aae_{  
{//nSplitter的缺省值为5 c6SXz%'k  
//default value of nSplitter is 5 jINI<[v[  
this("","","",5); )UyJ.!Fly  
} '6L@l  
U=5~]0g  
OU!."r`9  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z";(0%  
{ W{~ y< `D  
sSiteURL= sURL; s^Xs*T@~h  
sFilePath = sPath; \r [@A3O  
sFileName = sName; d]N_<@tx9  
this.nSplitter = nSpiltter; Jm"W+! E  
Hx!eCTO:*  
7U2B=]<e-  
} |I{3~+E h  
{CNJlr@z  
'%o^#gJp  
public String getSSiteURL() z#GSt ZT  
{ m!=5Q S3Z  
return sSiteURL; e>bARK<  
} ~ H/ZiBL@  
=YD<q:n4  
ukRmjHbLf  
public void setSSiteURL(String value) Mc$rsqDz  
{ E[4 vUnm-  
sSiteURL = value; L!,@_   
} =d]}7PO ~  
( GoPXh  
}}k*i0  
public String getSFilePath() 5u3KL A  
{ ?Mn~XN4F_  
return sFilePath; {dn:1IcN  
} 2b-g`60<  
u6| IKZ  
4;eD}g  
public void setSFilePath(String value) JAT%s %UC  
{ @AK&R~<  
sFilePath = value; @]p {%"$  
} =K}T; c  
PZlPC#E-  
bm4Bq>*=U  
public String getSFileName() kE|x'(x  
{ T8Q_JQ  
return sFileName; Hi*|f!,H?  
} };<?W){!H  
gQJLqs"F  
bbDm6,  
public void setSFileName(String value) iyXd"O  
{ &xGpbJG  
sFileName = value; #M5d,%?+#[  
} 5?([jAOf  
H4j1yD(d  
5(E&jKn&  
public int getNSplitter() 4jZB%tH  
{ 4^ U%` 1  
return nSplitter; F^S]7{  
} 69apTx  
ck3+A/ !z  
fNfa.0 s  
public void setNSplitter(int nCount) Ajo IL  
{ oN%zpz;OR  
nSplitter = nCount; 6a_U[-a9;  
} {<-wm-]mo  
} DiTpjk ]c`  
S\Le;,5Z  
l-S0Gn/'X  
/* ~*<`PDO?  
**Utility.java 9Oo`4  
*/ t%0c$c  
package NetFox; Lo5pn  
$)BPtGMGo  
\sfc!5G  
public class Utility { '>n&3`r5  
hw*u.46  
[Q J  
public Utility() zufsmY4P  
{ h.KgHMV`  
y,6kL2DM  
*[*q#b$j  
} }xi?vAaTl  
V{w &RJ  
//线程睡眠 )Q>Ao.  
public static void sleep(int nSecond) c_?^:xs:d  
{ ,2+d+Zuh  
try{ -Fu,oEj{*  
Thread.sleep(nSecond); kM&-t&7  
} $5&~gHc,  
catch(Exception e) "* N#-=MJF  
{ b{{ H@LTW  
e.printStackTrace (); 5 6.JB BZZ  
} P1B=fgT  
} >VQLC&u(  
svb7-.!  
//日志 PAtv#)h  
public static void log(String sMsg) <>Dw8?O  
{ Z P6p>?DQ  
System.err.println(sMsg); <t*<SdAq>`  
} Vsw:&$  
d_0(;'  
Uxik&M  
public static void log(int sMsg) ( ^@i(XQ  
{ p]/[ji  
System.err.println(sMsg); r|jM;  
} ~K99DK.  
} 9c }qVf-i  
4cM0f,nc+  
a?8)47)  
/* $Bl51Vj N  
**TestMethod.java UnYb}rF#%  
*/ O>a1S*mxP  
package NetFox; WBkx!{\z  
r]D U  
aR('u:@jHi  
public class TestMethod { -)3+/4Q(  
bZ OCj1  
-1d*zySL  
public TestMethod() T!>hPg  
{ ///xx/weblogic60b2_win.exe )b>misb/  
try{ F4WX$;1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V45adDiZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); / x$JY\cq`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6 w{_+=T  
fileFetch.start(); fjl 9*  
} ->.9[|lIg  
catch(Exception e){e.printStackTrace ();} ",Vx.LV  
RWo7_XO  
I"x|U[*B  
} /j4G}  
Mx`';z8~  
aX6}:"R2C  
public static void main(String[] args) ;' vkF  
{ 2nCc(F&+?  
new TestMethod(); XM*5I 4V  
} G/ ~gF7  
} % XZ&(  
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