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http断点续传简单实现(java)

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/* Q |1-j  
**SiteFileFetch.java yH<a;@C  
*/ qvHRP@  
package NetFox; Bj1{=Pvl  
import java.io.*; Or:a\qQ1  
import java.net.*; KB@F^&L {  
S!oG|%VuB#  
\""sf{S9  
public class SiteFileFetch extends Thread { Kf>]M|G c  
u6#FG9W7  
$>*TO1gb+  
SiteInfoBean siteInfoBean = null; //文件信息Bean Y;I>rC (  
long[] nStartPos; //开始位置 P(|+1$#[  
long[] nEndPos; //结束位置 C]01(UoSZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D-KQRe2@  
long nFileLength; //文件长度 aK+jpi4?  
boolean bFirst = true; //是否第一次取文件 IUZ@n0/T  
boolean bStop = false; //停止标志 K (!+l  
File tmpFile; //文件下载的临时信息 ?7k%4~H t  
DataOutputStream output; //输出到文件的输出流 =jEh#  
a}p}G\b|  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) >Y>>lE! k  
public SiteFileFetch(SiteInfoBean bean) throws IOException =[Z uE0c  
{ i*l-w4D^U  
siteInfoBean = bean; ]>T4\?aC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |A/)b78'u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >0c4C< _  
if(tmpFile.exists ()) @b]?Gg  
{ 9vL n#_  
bFirst = false; V/,@hv`+  
read_nPos(); Kh' 7N!  
} MpCK/eiC  
else /&jh10}H  
{ ~k[mowz0  
nStartPos = new long[bean.getNSplitter()]; 40i]I@:JK  
nEndPos = new long[bean.getNSplitter()]; D *Hy 2eZ.  
} xhTiOt6l  
^|kqy<<X  
W? SFt z  
uKF)'gj  
} | f}1bJE+  
H4Lvw8G  
~u^MRe|`  
public void run() Jv[c?6He  
{ ?ypX``3#s7  
//获得文件长度 93]67PL#+  
//分割文件 =F 9!)r  
//实例FileSplitterFetch }:zTz% _K  
//启动FileSplitterFetch线程 a?K3/0G  
//等待子线程返回 ZOIx+%/Vd#  
try{  O86[`,  
if(bFirst) E|~)"=  
{ XUK!1}  
nFileLength = getFileSize(); knb 9s`wR  
if(nFileLength == -1) UD6:X&Un  
{ Jb1L[sT2  
System.err.println("File Length is not known!"); 9o<5Z=  
} JIH6!  
else if(nFileLength == -2) At$[&%}  
{ I|eYeJ3  
System.err.println("File is not access!"); Mv%"aFC  
} E/5/5'gBJO  
else VxTrL}{(6  
{ z-g"`w:Lj  
for(int i=0;i<nStartPos.length;i++) (;6vT'hE  
{ uJ@C-/BD!M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _Gb O>'kE  
} X={Z5Xxr"  
for(int i=0;i<nEndPos.length-1;i++) w;=g$Bn  
{ kH|cB!?x  
nEndPos = nStartPos[i+1]; JQ"R%g` 8  
} g\~n5=-D  
nEndPos[nEndPos.length-1] = nFileLength; 8nKb mjM  
} d:&=|kKw  
} cy{ ado2  
QRFBMq}'  
M:/)|fk  
//启动子线程 L[rxs[7~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tH^]`6"QUa  
for(int i=0;i<nStartPos.length;i++) i[7<l&K]  
{ 2M$^|j:[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n=1_-)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8{)j"rghah  
nStartPos,nEndPos,i); l1#F1q`^t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }T1.~E  
fileSplitterFetch.start(); FA7q pc  
} U ,7O{YM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4Uzx2   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2, R5mL$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UVz}"TRq.  
nEndPos = " + nFileLength); =+ vl+h  
// fileSplitterFetch[nPos.length-1].start(); viXt]0  
@Lk!nP  
d,+a}eTP'  
//等待子线程结束 e4mAKB s!  
//int count = 0; /OtLIM+7~{  
//是否结束while循环 '5; /V  
boolean breakWhile = false;  U rL|r.  
LZ-&qh  
AdGDs+at,  
while(!bStop) e,8[fp-7  
{ 3 z~d7J  
write_nPos(); 6*r#m%|   
Utility.sleep(500); Zog&:]P'F  
breakWhile = true; fMl uVND  
`2l j{N  
3D^!U}E  
for(int i=0;i<nStartPos.length;i++) mnm 7{?#[  
{ IDn$w^"  
if(!fileSplitterFetch.bDownOver) +JlPQ~5  
{ SDHJX8Hq  
breakWhile = false; dW#T1mB  
break; 5h7M3s  
} ,We'A R3X  
} -.t/c}a#  
if(breakWhile) ]X\p\n'@j  
break; 'MK"*W8QRM  
?&_u$Nn  
sp8P[W1a  
//count++; eFXQ~~gOj  
//if(count>4) S!6 ? b5  
// siteStop(); 9?38/2kX4  
} :c}"a(|  
u6MHdCJ0y  
]9hXiY  
System.err.println("文件下载结束!"); .u3Z*+  
} peD7X:K\s  
catch(Exception e){e.printStackTrace ();} ^SvGSx i  
} }O+`X) 9  
oa<%R8T?@  
M"!{Dx~  
//获得文件长度 h,@tfd U^  
public long getFileSize() hUP?r/B  
{ d3jzGJrU}  
int nFileLength = -1; ?,  m_q+  
try{ 5Ei4$T  
URL url = new URL(siteInfoBean.getSSiteURL()); r(OH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'aqlNBG*  
httpConnection.setRequestProperty("User-Agent","NetFox"); q#_<J1)z  
YMr2Dv\y  
7w5C NV  
int responseCode=httpConnection.getResponseCode(); opv<r* !  
if(responseCode>=400) a?1lj,"~R  
{ )uRR!<"~  
processErrorCode(responseCode); Ge^(Ag}vE  
return -2; //-2 represent access is error %pj T?G7  
} 8z)J rO}  
dj2w_:&W  
}P\J?8  
String sHeader; kHz?vVE/l  
rk8Cea  
Dj9ecV`  
for(int i=1;;i++) EV[ BB;eb  
{ %v)+]Ds{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {&uN q^Ch  
//Utility.log(in.readLine()); ap wA  
sHeader=httpConnection.getHeaderFieldKey(i); +N2R'Phv  
if(sHeader!=null) g+%Pg@[  
{ ,Fzuo:{uy  
if(sHeader.equals("Content-Length")) vn1*D-?  
{ ]=G  dAW  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r,Tq";N'  
break; }DFZ9,gQ  
} (q}{;  
} ,buo&DT{L  
else ]6;G#  
break; * 3#RS  
} ZKF  #(G  
} QP7N#mh  
catch(IOException e){e.printStackTrace ();} G]RFGwGt  
catch(Exception e){e.printStackTrace ();} -7u_\XFk  
yW@YW_2;4  
@ S)p{T5G  
Utility.log(nFileLength); 4|h>.^  
8SOfX^;o  
Wxzh'c#\8  
return nFileLength; v-&@c  
} F@<^  
"sJ@_lp  
3U4h>T@s|  
//保存下载信息(文件指针位置) U[G5<&Z^  
private void write_nPos() &UIS17cT  
{ F5 7Kr5X  
try{ 3(3-#MD0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N[&(e d=  
output.writeInt(nStartPos.length); |\T!,~  
for(int i=0;i<nStartPos.length;i++) v(`5exWV  
{ of/' 9Tj  
// output.writeLong(nPos); >uR;^B5m  
output.writeLong(fileSplitterFetch.nStartPos); eCwR }m?_  
output.writeLong(fileSplitterFetch.nEndPos); {)wl`mw3  
} ?o`fX wE  
output.close(); gr\vC  
} RU+F~K<  
catch(IOException e){e.printStackTrace ();} Sh(XFUJ  
catch(Exception e){e.printStackTrace ();} {nH*Wu*^  
} .6A{   
suE#'0K  
n0b{Jg *  
//读取保存的下载信息(文件指针位置) M9QxF  
private void read_nPos() 3\j3vcuy  
{ '@f#GNRT  
try{ 17[vq!x6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :Fdk`aC  
int nCount = input.readInt(); d(F4-kBd  
nStartPos = new long[nCount]; tUhr gc  
nEndPos = new long[nCount]; p!7(a yu  
for(int i=0;i<nStartPos.length;i++) S4D~`"4 $/  
{ 8X)1bNGqhe  
nStartPos = input.readLong(); ,lQfsntk'  
nEndPos = input.readLong(); cB_ 3~=fV  
} 9 =D13s(C  
input.close(); 9d8U@=  
} fKNDl\SD  
catch(IOException e){e.printStackTrace ();} N >k,"=N /  
catch(Exception e){e.printStackTrace ();} J<-2dvq  
} T1M>N  
B&?xq)%*#  
9&Ny;oy#6  
private void processErrorCode(int nErrorCode) AME<V-5  
{ T;#:Y  
System.err.println("Error Code : " + nErrorCode); @T)>akEOt  
} YzYj/,?r  
/Y8{?  
}u.1$Y  
//停止文件下载 A?H.EZ  
public void siteStop() %:Y'+!bX  
{ W<M\ b#  
bStop = true; qhOV>j,d  
for(int i=0;i<nStartPos.length;i++) =po5Q6@i  
fileSplitterFetch.splitterStop(); +?+iVLr!l}  
9ZG__R3B1\  
m`#UV-$J  
} "tz`@3,5dN  
} w%eEj.MI|i  
//负责部分文件的抓取 iJzW3%E  
**FileSplitterFetch.java c:,K{ZR  
*/ cWp5pGIzfp  
package NetFox; dwz {Yw(  
Z(hRwIOF  
DHh30b$c  
import java.io.*; ;k8U5=6a  
import java.net.*; X@Yl<9|i  
lQ|i Ws  
\<x{U3q5  
public class FileSplitterFetch extends Thread { {%QWv%|  
.2/W.z2  
<v$yXA  
String sURL; //File URL :2-!bLo}&  
long nStartPos; //File Snippet Start Position ,e+S7 YX  
long nEndPos; //File Snippet End Position ^A$p)`KR  
int nThreadID; //Thread's ID J4jL%5t  
boolean bDownOver = false; //Downing is over s` o _ER  
boolean bStop = false; //Stop identical =:Lc-y>  
FileAccessI fileAccessI = null; //File Access interface 6Lz:J:Q)  
B^BbA-I  
AUPTtc`#Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Bu#\W  
{ Mf`@X[-;  
this.sURL = sURL; * NdL4c~  
this.nStartPos = nStart; yYvv!w+@Q  
this.nEndPos = nEnd; PZhpp"  
nThreadID = id; bf$4Z: Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fe7DS)U  
} zwdi$rM5  
9FmX^t$T  
qrY]tb^K  
public void run() X;3gKiD  
{ >?ckBU9  
while(nStartPos < nEndPos && !bStop) [-w+ACV~  
{ ~%u;lr  
*"sDsXo- I  
="s>lI-1a  
try{ YHI@Cj  
URL url = new URL(sURL); pLsJa?}R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @H|3e@5([  
httpConnection.setRequestProperty("User-Agent","NetFox"); #<gD@Jybu  
String sProperty = "bytes="+nStartPos+"-"; z?Qt%1q  
httpConnection.setRequestProperty("RANGE",sProperty); crRYgr  
Utility.log(sProperty); v9l|MI15V  
+t<'{KZ7;  
Hb@PQcj  
InputStream input = httpConnection.getInputStream(); ,Cj` 0v#  
//logResponseHead(httpConnection); R;F z"J  
)r6d3-p1  
H1a<&7  
byte[] b = new byte[1024]; Rx.dM_S  
int nRead; |gM@}!DL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]VHO'z\m  
{ .{66q#.  
nStartPos += fileAccessI.write(b,0,nRead); Ugv"A;l  
//if(nThreadID == 1) Lb%:u5X\D@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W3Dtt-)E  
} DeGcS1_?  
hV[=  
_sC kBDl-  
Utility.log("Thread " + nThreadID + " is over!"); "oo j;  
bDownOver = true; 5)<}a&;{  
//nPos = fileAccessI.write (b,0,nRead); {%XDr,myd  
} Z)RV6@(  
catch(Exception e){e.printStackTrace ();} Ib0@,yS[  
} c~{)vL0K  
} 992cy2,Fb  
WcKL=Z?(  
ys Td'J  
//打印回应的头信息 ^fT?(y_= e  
public void logResponseHead(HttpURLConnection con) *N3X"2X:  
{ Xjnv8{X  
for(int i=1;;i++) _U`1BmTC2  
{ UeN+}`!l  
String header=con.getHeaderFieldKey(i); <#No t1R  
if(header!=null) GB` G(a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); av4g/7=  
Utility.log(header+" : "+con.getHeaderField(header)); ip2BvN&  
else {igVuZ(>en  
break; Evb %<`gd  
} qn#f:xltu  
} l]KxUkA+  
-`} d@x  
Kf'oXCs  
public void splitterStop() J?84WS  
{ `HJRXoLySW  
bStop = true; 9zD^4j7  
} a^.5cJ$]  
f)%8*B  
_Sn7z?  
} br_D Orq|  
yfCdK-9+B  
%Astfn(U{4  
/* [+z*&~'  
**FileAccess.java Qr$Ay3#k  
*//文件访问(定位,写) \KT}T  
package NetFox; 9ld'SB:#  
import java.io.*; */E5<DO  
=U_O;NC  
LFT)_DG7(  
public class FileAccessI implements Serializable{ .m_-L Y-  
|)IS[:X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pG(%yIiAi  
RandomAccessFile oSavedFile; `w/`qG:dK  
long nPos; GV(@(bI*  
DSc:>G  
p:CpY'KV_  
public FileAccessI() throws IOException D+xHTQNTL  
{ 3 CArUP  
this("",0); @"gWv s  
} $l<(*,,l  
kqyPb$Wy  
tv8}O([  
public FileAccessI(String sName,long nPos) throws IOException mu#  a  
{ (_$'e%G0  
oSavedFile = new RandomAccessFile(sName,"rw"); ?5MOp  
this.nPos = nPos; IW-lC{hK  
oSavedFile.seek(nPos); (_'Efpg|  
} si.w1  
yttIA/  
tf_<w?~  
public synchronized int write(byte[] b,int nStart,int nLen) AQa;D2B$  
{ hRKA,u/G  
int n = -1; <u%&@G$F>  
try{ 5 Yf T  
oSavedFile.write(b,nStart,nLen); _"R /k`8  
n = nLen; A6# 5 z  
} 1Xj>kE:  
catch(IOException e) *aT\V64  
{ )mF;^3  
e.printStackTrace (); vS_Ji<W~E  
} N 56/\1R  
\c.MIDp"  
"g>, X[g  
return n; )T26 cT$  
} wtpz ef=  
jizp\%W+  
B+8B<xZ  
} SWrP0Qjc  
j`A3N7;  
-"Hy%wE  
/* ~v+A6N:qC  
**SiteInfoBean.java NwPC9!*  
*/ p&|:,|jo5  
package NetFox; ytg' {)  
c mI&R(  
uF89B-t  
public class SiteInfoBean { 236,o {9e  
 8%W(",nd  
ROc)LCA  
private String sSiteURL; //Site's URL z.%K5vrO>  
private String sFilePath; //Saved File's Path ^a+H`RD  
private String sFileName; //Saved File's Name sj& j\<(  
private int nSplitter; //Count of Splited Downloading File C`LHFqv  
lZ![?t}2`  
c.;}e:)s  
public SiteInfoBean() wz{]CQ7"  
{//nSplitter的缺省值为5 wW?/`>@  
//default value of nSplitter is 5 vjz*B$  
this("","","",5); Gl@}b\TB  
} O ELh6R  
~ M!s0jT  
]= nM|e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) TCI%Ox|a  
{ PH]/*LEj  
sSiteURL= sURL; 0M_~@E*&  
sFilePath = sPath; 3!:?OUhx  
sFileName = sName; EiP#xjn?c  
this.nSplitter = nSpiltter; 1Ff Sqd  
:497]c3#5C  
pX~X{JTaL)  
} M~jV"OF=  
S%t*!  
e[)oT  
public String getSSiteURL() y6C3u5`  
{ O h{ >xg  
return sSiteURL; ]6BV`r]  
} ^;@Q3~DpP%  
Y)oF;ko:  
^vA"3Ixb!  
public void setSSiteURL(String value) $>csm  
{ }> pNf  
sSiteURL = value; luj UEHzp  
} 7j22KQ|EX^  
|k ]{WCD]  
S(\<@S&  
public String getSFilePath() Ga M:/.  
{ R@[gkj  
return sFilePath; f%2>pQTq@)  
} xh) h#p.  
}mx>3G{d  
,VdNP  
public void setSFilePath(String value) e [ 9  
{ 2YV*U_\L  
sFilePath = value; oM~;du  
} Pv#>j\OR&  
(+w>hCI  
h .%)RW?  
public String getSFileName() ^^FqN;  
{ I"5VkeIx  
return sFileName; A0f98 ?j^  
} Uxl7O4J@H  
A<$w }Fy;  
de<T5/  
public void setSFileName(String value) ]b6gZ<  
{ }S_#*N)i  
sFileName = value; zY^QZceq"  
} X]T&kdQ6q  
s`63 y&Z[  
|h6u%t2AY  
public int getNSplitter() {)L*\r  
{ 8v V<A*`  
return nSplitter; 1w#vy1m J  
} -qG7,t  
ihD|e&  
|nY+Nen7  
public void setNSplitter(int nCount) \O)u' Bu  
{ tR(L>ZG{  
nSplitter = nCount; ~*L@|?  
} |#EI(W?`  
} O@>{%u  
Hk?E0.  
-^t&U] g  
/* T#a6X;9P  
**Utility.java uzL|yxt  
*/ ~R7{gCqdr  
package NetFox; - XB[2h  
Kir|in)r0  
%:y"o_X_  
public class Utility { BJjxy0+  
L08" 8\  
@'"7[k!y;  
public Utility() Tx(=4ALY  
{ #-/_J?  
\3whM6tK  
}3R:7N`,|  
} Ca0t}`<S  
,&jjp eZP  
//线程睡眠 >HRLL\u9  
public static void sleep(int nSecond) hroRDD   
{ 29NP!W /g  
try{ JB HnJm  
Thread.sleep(nSecond); B|SX?X  
} BXr._y, cr  
catch(Exception e) Pcr;+'q  
{ ]o`FF="at  
e.printStackTrace (); vr$z6m ^  
} #J%Fi).^)  
} dfs1BV'  
WiFZY*iu5  
//日志 Rr>""  
public static void log(String sMsg) )==Qo/N:  
{ Ms A)Y  
System.err.println(sMsg); )`zfDio-1V  
} YrTjHIn~w  
4<U6jB5  
{>l`P{{y  
public static void log(int sMsg) 1 w9Aoc  
{ cQ/T:E7$`  
System.err.println(sMsg); e3kdIOu5  
} c1StA  
} ;^P0+d^5C  
m\ /V0V\  
G_?qY#"(  
/* hj[sxC>z5  
**TestMethod.java q|e<b  
*/ r-o6I:y  
package NetFox; 9R4q^tGR\  
LU@+O12  
I^S{V^Ty  
public class TestMethod { @fSqGsSk  
2LH.If  
U KdCG.E9^  
public TestMethod() U6oab9C?k  
{ ///xx/weblogic60b2_win.exe +K[H! fD  
try{ L!kbDbqn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); LzkwgcR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BmFs6{>~c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a5%IjgQ&z  
fileFetch.start(); g [+_T{  
} sxQMfbN  
catch(Exception e){e.printStackTrace ();} Cg&cz]*q|  
o^~KAB7  
XJi^gT N  
} <2 S?QgR,  
l%$co07cX  
B!z5P" C(~  
public static void main(String[] args) G7H'OB &  
{ d<4q%y'X{  
new TestMethod(); yS(tF`H[  
} QsH Fk5)  
} P[C03a!lXg  
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