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http断点续传简单实现(java)

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/* mi$*,fz  
**SiteFileFetch.java 5SmgE2}  
*/ aG/L'weR  
package NetFox; &io*pmUm6  
import java.io.*; }TAHVcX*p  
import java.net.*; D*o[a#2_  
*heX[D &>)  
ttC+`0+H  
public class SiteFileFetch extends Thread { nV+]jQ~o  
nXcOFU  
:ODG]-QF  
SiteInfoBean siteInfoBean = null; //文件信息Bean F5;x>;r  
long[] nStartPos; //开始位置 s9}VnNr  
long[] nEndPos; //结束位置 X |X~|&j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rJ}k!}G  
long nFileLength; //文件长度 ' CO3b,  
boolean bFirst = true; //是否第一次取文件 ]NgEN  
boolean bStop = false; //停止标志 :6X?EbXhK  
File tmpFile; //文件下载的临时信息 m;"dLUb  
DataOutputStream output; //输出到文件的输出流 U `<?~Bz  
[P?.( *  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6N.+  
public SiteFileFetch(SiteInfoBean bean) throws IOException 60&4?<lR4  
{ "<I*ViZ  
siteInfoBean = bean; dTW3mF4=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X7gtR|[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Rt10:9Kz$  
if(tmpFile.exists ()) YXWlg%s  
{ -?&s6XA%#  
bFirst = false; .~Z@y#  
read_nPos(); F),wj8#~>-  
} a4iq_F#NF  
else |=9=a@l]P  
{ j9Y'HU5"  
nStartPos = new long[bean.getNSplitter()]; +HOHu*D  
nEndPos = new long[bean.getNSplitter()]; SvD^'( x  
} V}UYr Va#9  
\a}W{e=FNT  
k+FiW3-  
|&]04  
} -^%YrWgd?  
h16i]V  
M8wEy_XB1  
public void run() QL4BD93v  
{ J|A:C[7 2  
//获得文件长度 f.&((z?rC  
//分割文件 t*'U|K4L/  
//实例FileSplitterFetch -N]%) Hy  
//启动FileSplitterFetch线程 nm597WeZp  
//等待子线程返回 6$|!_94>*)  
try{ 9s}y*Vp  
if(bFirst) pZv>{=2hOS  
{ +P?^Yx0d  
nFileLength = getFileSize(); (]l}QR%Bxu  
if(nFileLength == -1) a9CK4Kg  
{ (ug^2WG Yq  
System.err.println("File Length is not known!"); ?nya;Z-~Hc  
} 56 raZC  
else if(nFileLength == -2) *3>$ f.QU  
{ :UgCP ~Y  
System.err.println("File is not access!"); R%Y#vUmBV{  
} 'U" ub2j  
else $J] b+Bp  
{ fq2t^c|$  
for(int i=0;i<nStartPos.length;i++) L~])?d  
{ OAhCW*B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /Ky xOb)  
} \-?@ &' :  
for(int i=0;i<nEndPos.length-1;i++) >(aGk{e1  
{ b\l +S2  
nEndPos = nStartPos[i+1]; i!jR>+  
} u(!@6%?-  
nEndPos[nEndPos.length-1] = nFileLength; (3>Z NTm  
} 5#SD$^  
} &b#O=LF  
n 7Bua  
j\Z/R1RcW  
//启动子线程 )j[rm   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UvtSNP&/2d  
for(int i=0;i<nStartPos.length;i++) 8=#J:LeXj  
{ dfmxz7V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eaI!}#>R +  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8 )w75+&  
nStartPos,nEndPos,i); 7Q(5Nlfcz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6H\apgHm  
fileSplitterFetch.start(); &Jr~ )o   
} D/$$"AT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J,bE[52  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QlHxdRK`.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n2JwZ?  
nEndPos = " + nFileLength); BWbM$@'x  
// fileSplitterFetch[nPos.length-1].start(); `6.rTs $<  
HktvUJ(Ii  
;&N;6V"}  
//等待子线程结束 _Co*"hl>2  
//int count = 0; BN?OvQ  
//是否结束while循环 UoLvc~n7  
boolean breakWhile = false; Zljj  
%b H1We  
y3 R+060\3  
while(!bStop) Kug_0+gI  
{ "Yo.]P U  
write_nPos(); GJLlMi  
Utility.sleep(500); ib4shaN`  
breakWhile = true; lJfn3  
ctv=8SFv(  
}K!)Z}8  
for(int i=0;i<nStartPos.length;i++) uHv9D%R  
{ n6PXPc  
if(!fileSplitterFetch.bDownOver) ;BsPms@U  
{ Q.q'pJ-  
breakWhile = false; ov{  
break; VFZ_Vw  
} }=':)?'-.  
} cI9}YSk  
if(breakWhile) 5AWIk,[  
break; qjsS2,wM  
@w)Vt $+b]  
ohHKZZ  
//count++; J!$q"0G'WT  
//if(count>4) p*T`fOL  
// siteStop(); io[$QTY  
} q F \a]e  
`g2DN#q[0  
\;z *j|;B  
System.err.println("文件下载结束!"); bp06xHMu  
} E1U~ ew  
catch(Exception e){e.printStackTrace ();} ;TAf[[P  
} f\W1u#;u)  
JsfX&dX0  
-.8 nEO3  
//获得文件长度 w&eX)!  
public long getFileSize() )Q_^f'4  
{ Q3t9J"=1g  
int nFileLength = -1; ;+%(@C51GE  
try{ p#VA-RSUQ|  
URL url = new URL(siteInfoBean.getSSiteURL()); 2qY`*Y.2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zj ;'0Zu  
httpConnection.setRequestProperty("User-Agent","NetFox"); TG\3T%gH/s  
X~DI d  
[ 7W@/qqv  
int responseCode=httpConnection.getResponseCode(); l2))StEm  
if(responseCode>=400) R^`#xQ  
{ RR u1/nam  
processErrorCode(responseCode); _b+=q:$/  
return -2; //-2 represent access is error >tfy\PY:  
} W}<'Y@[ ,  
g1JBssw&m  
qVOlUH  
String sHeader; }B{bM<dF  
K,7IBv,B[  
$ e<&7  
for(int i=1;;i++) A4lh`n5%  
{ O1+2Z\F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yF &"'L  
//Utility.log(in.readLine()); A.a UWh  
sHeader=httpConnection.getHeaderFieldKey(i); ,J|8P{ZO  
if(sHeader!=null) J. ;9-  
{ ,qF;#nB-  
if(sHeader.equals("Content-Length")) -!OFt}  
{ Ccmo(W+0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,/O,j SRk  
break; 4{?Djnh  
} =2[5 g!qX  
} 1wX0x.4d  
else bLrC_  
break; 26yjQ  
} :"Vfn:Q  
} Nf.6:=  
catch(IOException e){e.printStackTrace ();} Tw|cgB  
catch(Exception e){e.printStackTrace ();} |5o0N8!b[  
6xk~Bt  
E1(2wJ-3"  
Utility.log(nFileLength); _^+z2m+ ~N  
NwH`t#zd  
>k gL N  
return nFileLength; biTET|U`$  
} h,-8( S  
\ /(;LHWQ  
%d<uOCf\Q  
//保存下载信息(文件指针位置) mJBvhK9%  
private void write_nPos() 1bW[RK;GE  
{ dd+[FU  
try{ 0G-M.s}A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .VFa,&5;3  
output.writeInt(nStartPos.length); N*~G ]  
for(int i=0;i<nStartPos.length;i++) 3l?D%E]P  
{ vYT%e:8)q  
// output.writeLong(nPos); `m N*"1p-  
output.writeLong(fileSplitterFetch.nStartPos); 5,3Yt~\m  
output.writeLong(fileSplitterFetch.nEndPos); GfEg][f  
} ';g]!XsY)  
output.close(); V2< 4~J2:9  
} :JBvCyj4PE  
catch(IOException e){e.printStackTrace ();} E^uWlUb{  
catch(Exception e){e.printStackTrace ();} !+qy~h  
} h,:8TMJRRN  
de.!~%D  
K8,fw-S%  
//读取保存的下载信息(文件指针位置) oLJP@J  
private void read_nPos() w Phs1rL  
{ W0vdU;?%  
try{ {fi:]|<1h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $tGk,.#j  
int nCount = input.readInt(); ![ & go  
nStartPos = new long[nCount]; NXQdyg,  
nEndPos = new long[nCount]; m2!y;)F0  
for(int i=0;i<nStartPos.length;i++) seT?:PCA  
{ i3T]<&+j5  
nStartPos = input.readLong(); *], ]E;  
nEndPos = input.readLong(); D8u_Z<6IjI  
} &|t*9 D  
input.close(); B+y r 6Q.  
} `(j}2X'[  
catch(IOException e){e.printStackTrace ();} (A.%q1h  
catch(Exception e){e.printStackTrace ();} jl# )CEx  
} %xE9vN;  
*ujn+0)[  
"Dbjp5_  
private void processErrorCode(int nErrorCode) ^j1?LB  
{ K1S)S8.EZ8  
System.err.println("Error Code : " + nErrorCode); uj@rv&  
} zY@|KV"^r  
aBX^Wd  
(h NSzG\  
//停止文件下载 tOn_S@/r  
public void siteStop() Y {]RhRR  
{ %T3L-{s5  
bStop = true; ,U_p6 TV5  
for(int i=0;i<nStartPos.length;i++) K 2J DG.<  
fileSplitterFetch.splitterStop(); vAW+ ,Rfj  
cwK 6$Ax  
B2UQO4[w  
} h#K863  
} X( m&  
//负责部分文件的抓取 psb$rbu7[  
**FileSplitterFetch.java ;\yVwur  
*/ ]ee%=+'  
package NetFox; IaDc hI  
rYI9?q  
'2+Rb7V  
import java.io.*; ADoxma@  
import java.net.*; q5il9*)d (  
=y" lX{}G  
q.L0rY!  
public class FileSplitterFetch extends Thread { HhfuHZ<  
MH{$"^K  
Vw7NLTE}`  
String sURL; //File URL S?.2V@Ic  
long nStartPos; //File Snippet Start Position m S[Vl6  
long nEndPos; //File Snippet End Position eup#.#J  
int nThreadID; //Thread's ID 0w?\KHT  
boolean bDownOver = false; //Downing is over ;Wjb}_V:_  
boolean bStop = false; //Stop identical !2oe;q2X[G  
FileAccessI fileAccessI = null; //File Access interface OyVdQ".  
7[ )4k7  
?YR/'Vq97  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z IfhC'  
{ "qEHK;  
this.sURL = sURL; Q>s>@hw  
this.nStartPos = nStart; <'H^}gQow  
this.nEndPos = nEnd; U#v??Sl  
nThreadID = id; LO8V*H(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +.UdEIR";M  
} 0tVZvXgTu  
<6k5nEh  
n m4+$GW   
public void run() cPe0o'`[  
{ gD0O7KO  
while(nStartPos < nEndPos && !bStop) Y2i:ZP  
{ ^S*~<0NQ'  
(JS1}T  
xk=5q|u_-  
try{ ;'!G?)PZ  
URL url = new URL(sURL); b!VaEK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )&[S*g  
httpConnection.setRequestProperty("User-Agent","NetFox"); d[ql7  
String sProperty = "bytes="+nStartPos+"-"; Tvr2K84l  
httpConnection.setRequestProperty("RANGE",sProperty); `9SRiy  
Utility.log(sProperty); (Nd5VuI  
gE^ {@^  
" SkTVqm  
InputStream input = httpConnection.getInputStream(); GD?4/HkF  
//logResponseHead(httpConnection); #)`N  
L2Ynv4llm  
COJny/FT|  
byte[] b = new byte[1024]; 0?525^   
int nRead; Y9fktg.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9:N@+;|T  
{ h32QEz-+  
nStartPos += fileAccessI.write(b,0,nRead); E!;giPq*n  
//if(nThreadID == 1) !kZ9Ox9^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Uu xbN-u  
} ur^)bp<n  
gZ6]\l]J{  
_y{z%-  
Utility.log("Thread " + nThreadID + " is over!"); )`?Es8uW  
bDownOver = true; n@[&SgZq  
//nPos = fileAccessI.write (b,0,nRead); jt-Cy  
} kxU <?0  
catch(Exception e){e.printStackTrace ();} -miWXEe@l  
} C=L_@{^Rgb  
} :X-Z|Pv8  
lquY_lrri  
iLf:an*vH  
//打印回应的头信息 NBzyP)2)  
public void logResponseHead(HttpURLConnection con) ed$g=qs>  
{ |UvM [A|+  
for(int i=1;;i++) )3g7dtq}  
{ jH26-b<  
String header=con.getHeaderFieldKey(i); y&T(^EA;  
if(header!=null) p#HbN#^Hy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4Eh 2sI  
Utility.log(header+" : "+con.getHeaderField(header)); +#~=QT9  
else K 2PV^Y  
break; DIO @Zo  
} X^mv sY  
} AA&398F  
| _/D-m*  
]nE_(*w  
public void splitterStop() &>kklP  
{ $ c4Q6w  
bStop = true; csZIBi  
} EacqQFErl  
5m2(7FC%su  
No8~~  
} <1#v}epD#  
/5M@>A^?'  
z^=.05jB  
/* o3*IfD  
**FileAccess.java ;n?72&h  
*//文件访问(定位,写) #q.Q tDz  
package NetFox; c|q!C0X[  
import java.io.*; ct='Z E  
r:.5O F}  
^/`:o}7K7  
public class FileAccessI implements Serializable{ Hm2}xnY  
5fi6>>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 IE*GF27n  
RandomAccessFile oSavedFile; ;EstUs3  
long nPos; is&A_C7yg  
4Fhiac  
S^|Uzc  
public FileAccessI() throws IOException 5P_%Vp`B2  
{ ]Cy1yAv={  
this("",0); t6p}LNm(V  
} AkdONKO8{  
sOA!Sl  
T)Z2=5V  
public FileAccessI(String sName,long nPos) throws IOException lV!ecJw$  
{ rqk1 F~j|  
oSavedFile = new RandomAccessFile(sName,"rw"); 3c] oU1GfF  
this.nPos = nPos; dA-ik  
oSavedFile.seek(nPos); wWm 1G)  
} ^SnGcr|a'  
]F5?>du@~  
q,-bw2   
public synchronized int write(byte[] b,int nStart,int nLen) +P,hT  
{ UlQZw*ce  
int n = -1; 5sui*WH  
try{ zt{?Nt b  
oSavedFile.write(b,nStart,nLen); I12WOL q  
n = nLen; !J ")TP=  
} i/QE)"B"q  
catch(IOException e) w^tNYN,i  
{ prE~GO7Z  
e.printStackTrace (); 9?B}CCE<LR  
} J =o,: 3"  
"e62g  
ZY-UQ4_|u  
return n; $ hwJjSZ0  
} s6SG%Vd  
nokk! v/  
tWL3F?wd  
} LY}%|w  
# JHicx\8l  
:9H=D^J  
/* WCxt-+#  
**SiteInfoBean.java b['Jr% "O  
*/ ~M`-sSjZs  
package NetFox; JSX-iHhW  
/CX_@%m}e=  
v-2_#  
public class SiteInfoBean { Arh0m. w  
[ L% -lJ  
cn (-{dCXM  
private String sSiteURL; //Site's URL P!yE{_%  
private String sFilePath; //Saved File's Path 0g% `L_e_  
private String sFileName; //Saved File's Name 6jjmrc[#}X  
private int nSplitter; //Count of Splited Downloading File '5zolp%St  
7 J$  
~oO>6  
public SiteInfoBean() q9rY++Tv  
{//nSplitter的缺省值为5 -g8G47piX:  
//default value of nSplitter is 5 "PH}\Dl=  
this("","","",5); b:Oa4vBa  
} dc UaZfON  
_r+2o-ZR  
7Pspx'u  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nDx}6}5)  
{ ?EF[OyE  
sSiteURL= sURL; V'(yrz!   
sFilePath = sPath; t|q@~B :  
sFileName = sName; ^eke,,~  
this.nSplitter = nSpiltter; 0Q>f,}W%>  
M qq/k J  
iev02 8M  
} Vg9n b  
GUyMo@g  
!}7FC>Cx  
public String getSSiteURL() sd|5oz )  
{ Y?G9d6]Lk6  
return sSiteURL; h^ wu8E   
} BUR96YN.  
aOZSX3;wg  
`8^4,  
public void setSSiteURL(String value) r|2Y|6@  
{ 4D(5WJ&  
sSiteURL = value; ]6)^+(zU  
} C-Y~T;53  
1FC'DH!  
x { Z_rD  
public String getSFilePath() jG8W|\8  
{ Q;A1&UA2  
return sFilePath; :^~I@)"ov  
} v eP)ElX  
Ni]V)wGE;  
.}'49=c  
public void setSFilePath(String value) 7Gg3$E+#*  
{ }pk)\^/w/  
sFilePath = value; ;!H<W[  
} 2JY]$$K7  
~,j52obR6Z  
MDkcG"O  
public String getSFileName() @'UbTB!  
{ .W4P/P w'  
return sFileName; XL9smFq  
} \*] l'>x1  
kpT>xS^6<  
ko-|hBNv  
public void setSFileName(String value) Cq mtO?vne  
{ hp ?4w),  
sFileName = value; 6&jW.G8/  
} KVQ^-^  
@)[Q6w`x  
}J=>nL'B  
public int getNSplitter() p5RnFe l  
{ @E Srj[  
return nSplitter; vTE3-v[i  
} +fh@m h0[  
$;GH -+  
QH z3  
public void setNSplitter(int nCount) 3y#0Lb-y  
{ 'OrGt_U  
nSplitter = nCount; _p;>]0cc.  
} c*>8VW>  
} 4oxAC; L  
Q,pnh!.-c  
uJxT)m!/  
/* An0Dq jR  
**Utility.java h2k"iO }  
*/ ^,-2";2Xh  
package NetFox; +pcGxje\  
r{+P2MPW  
3C[#_&_l  
public class Utility { qr$h51C&  
dWc'RwL  
SSr#MIS?  
public Utility() AW{"9f4  
{ \zCw&#D0Z  
h7 r *5E  
I 68Y4s  
} asEk 3  
pW[KC!  
//线程睡眠 -BV8,1  
public static void sleep(int nSecond) |B{@noGX  
{ rXh*nC  
try{ +aY]?]  
Thread.sleep(nSecond); ey/{Z<D  
} ]Rk4"i  
catch(Exception e) ;!~&-I0l  
{ G'#f*) f  
e.printStackTrace (); b((> ?=hh  
} 5%r:hO @S  
} PTS dW~3  
4Tdp;n\F  
//日志 uM"_3je{W2  
public static void log(String sMsg) rp&XzMwC4  
{ pie8 3Wy>  
System.err.println(sMsg); o;kxu(>yL'  
} qr@ <'wp/  
-){aBMOv3  
,K W IuCU;  
public static void log(int sMsg) f>CJ1 ;][{  
{ GQH15_  
System.err.println(sMsg); 5+DId7d'n  
} v\Y8+dD  
} Q8H+=L:  
-F$v`|(O+  
v ^R:XdH  
/* UdOO+Z_K%  
**TestMethod.java YB}m1 g`  
*/ 0$g;O5y"i  
package NetFox; _LSp \{Z  
\\ZCi`O  
e"(SlR  
public class TestMethod { I7 = 4%)A  
;F;Vm$  
FP<mFqy  
public TestMethod() .du2;` [$r  
{ ///xx/weblogic60b2_win.exe BUs={"Pa  
try{ T -p~8=I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3\ {?L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "wR1=&gk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ie]k/qw+Y  
fileFetch.start(); =E w<s5C@  
} eH ]9"^> o  
catch(Exception e){e.printStackTrace ();} 8-"D.b4  
G]n_RP$G  
6r.#/' "  
} 2!_DkE  
w9w=2 *  
SE$~Wbj?  
public static void main(String[] args) 9e*o$)j_  
{ UOpSH{N  
new TestMethod(); ,m Nd#  
} wEF"'T  
} ][dst@?8Oz  
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