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http断点续传简单实现(java)

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/* b-Q>({=i  
**SiteFileFetch.java I( 7NQ8H x  
*/ G.dTvLv  
package NetFox; /?F/9hL  
import java.io.*; (tw)nF  
import java.net.*; &/]Fc{]^$f  
q0r>2c-d  
|kV*Jc k  
public class SiteFileFetch extends Thread { q6`b26  
mah JSz(3  
ktBj|-'>  
SiteInfoBean siteInfoBean = null; //文件信息Bean ZO$m["|  
long[] nStartPos; //开始位置 91-o}|3v  
long[] nEndPos; //结束位置 I5n^,@md  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^mO~ W!"  
long nFileLength; //文件长度 V"G*N<q  
boolean bFirst = true; //是否第一次取文件 WQL\y3f5  
boolean bStop = false; //停止标志 S<@7_I  
File tmpFile; //文件下载的临时信息 %Ax3;g#  
DataOutputStream output; //输出到文件的输出流 E3gh?6  
Tl[!=S  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9}F*P669f  
public SiteFileFetch(SiteInfoBean bean) throws IOException e:n<EnT  
{ !1 8clL  
siteInfoBean = bean; aa#Y=%^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =sJ7=39  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H0`]V6+<f  
if(tmpFile.exists ()) -0{r>,&Mm  
{ #S*/bao#  
bFirst = false; |\IN.W[EL  
read_nPos(); G5aieD.#  
} Ne{?:h.!  
else '2nhv,|.U  
{ 27O|).yKX  
nStartPos = new long[bean.getNSplitter()]; @ H7d_S  
nEndPos = new long[bean.getNSplitter()]; F{~{Lthc  
} _Wq  
cacr=iX  
D"rK(  
J1sv[$9  
} 8xV9.4S  
$r8 ^0ZRr  
QoIT*!  
public void run() vyX\'r.~7  
{ r6} |hpJ8  
//获得文件长度 Et/\xL  
//分割文件 @As[k2  
//实例FileSplitterFetch *%fi/bimG  
//启动FileSplitterFetch线程 :xv!N*Le  
//等待子线程返回 vK\%%H  
try{ Y^7$t^&  
if(bFirst) -$jEfi4I  
{ W~~7 C,!  
nFileLength = getFileSize(); ;HJLs2bP  
if(nFileLength == -1) I]<_rN8~o  
{ B!_mC<*4`X  
System.err.println("File Length is not known!"); (# Gw1  
} MLje4  
else if(nFileLength == -2) ke]Lw  
{ rrqR}}l  
System.err.println("File is not access!"); LO khjHR  
} dx &'fe*?  
else `YLD`(\  
{ Yu[ t\/  
for(int i=0;i<nStartPos.length;i++) f~y%%+{p  
{ ?:8ido#-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +*T7@1  
} Dhw(#{N  
for(int i=0;i<nEndPos.length-1;i++) UU mTOJr  
{ $M lW4&a|  
nEndPos = nStartPos[i+1]; Ax?y  
} "UGY2skf;  
nEndPos[nEndPos.length-1] = nFileLength; _w/EP  
} D!NQ~'.a=2  
} r(aLEJ"u?  
6)-X  
Ov4y %Pj  
//启动子线程 o( RG-$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (\a]"g,]v  
for(int i=0;i<nStartPos.length;i++) wrbLDod /  
{ Iw&vTU=2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {fF3/tL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?NR A:t(}  
nStartPos,nEndPos,i); wF,UE _  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iH@yCNE"  
fileSplitterFetch.start(); Y/ >&0wj)d  
} X4AyX.p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZP *q4:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sCis4gX.]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2`>ToWN!  
nEndPos = " + nFileLength); 9{}1r2xW  
// fileSplitterFetch[nPos.length-1].start(); wEE\+3b)  
#Jn_c0  
?R Oqn6k&c  
//等待子线程结束 ~\.w^*$#Y  
//int count = 0; ^3{TZ=_;|  
//是否结束while循环 OK6] e3UO  
boolean breakWhile = false; ;04Ldb1{|3  
L ugn 3+  
Rhz_t@e  
while(!bStop) `m>*d!h=  
{ :x{NBvUIc  
write_nPos(); 65p?Igb  
Utility.sleep(500); #H{<gjs]  
breakWhile = true; ( Qcp{q  
Y/ee~^YxK'  
`m?c;,\  
for(int i=0;i<nStartPos.length;i++) qT"Q1xU[  
{ Jd(,/q  
if(!fileSplitterFetch.bDownOver) | 8=nL$u  
{ ,:`4%  
breakWhile = false; a1.Ptf eW|  
break; _$f9]bab  
} \ 3?LqJ  
} U,gti,IX^  
if(breakWhile) ]dk8lZ;bo  
break; YZ7|K<   
kc @[9eV  
zG9Y!SY\-  
//count++; Q7$.LEioN  
//if(count>4) @,u/w4  
// siteStop(); h0-hT   
} /D^"X 4!"  
:GW&O /Yo  
?) [EO(D  
System.err.println("文件下载结束!"); }!/$M\w  
} NqEA4C  
catch(Exception e){e.printStackTrace ();} }_;!hdY q  
} g'=B%eO$j:  
Tp?y8r  
x.zbD8l/9  
//获得文件长度 dd%h67J2<  
public long getFileSize() : G`hm{  
{ DrBUe'RH:M  
int nFileLength = -1; \ZhfgE8{%  
try{ ~r$jza~o(  
URL url = new URL(siteInfoBean.getSSiteURL()); $m+sNEAa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UIAj]  
httpConnection.setRequestProperty("User-Agent","NetFox"); x-<)\L&  
9Xl5@%uz?z  
& jczO-R^  
int responseCode=httpConnection.getResponseCode(); 6{+{lBm=y  
if(responseCode>=400) _5m#2u51i  
{ w'fT=v)  
processErrorCode(responseCode); P*@2.#oO  
return -2; //-2 represent access is error ~L_hZso4  
} EV^~eTz  
-gas?^`  
=;|QZ"%E  
String sHeader; FwY&/\J7V  
f<*Js)k  
]M[#.EX  
for(int i=1;;i++) I}t3 p|z  
{ 0zCw>wBPW  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r"a5(Q;n  
//Utility.log(in.readLine()); vZ N!Zl7S  
sHeader=httpConnection.getHeaderFieldKey(i); f1)x5N  
if(sHeader!=null) n?ctLbg  
{ qYf |Gv  
if(sHeader.equals("Content-Length")) ofMY,~w  
{ U_$qi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bb`':3%  
break; ;?~$h-9)  
} )r z+'|,  
} 1>Dl\czn  
else 5"]~oPK  
break; P"?FnTbv[  
} -}4NT{E  
} pge++Di  
catch(IOException e){e.printStackTrace ();} ?@t  d  
catch(Exception e){e.printStackTrace ();} pD2<fP_  
,7)C"  
RQB]/D\BO  
Utility.log(nFileLength); Gqcz< =/  
kR@Yl Yo  
G #T<`>T  
return nFileLength; B_l{<  
} m6yIR6H  
8W+gl=C~  
JwRF(1_sM  
//保存下载信息(文件指针位置) `)h6j)xiQ  
private void write_nPos() J~iBB~x.  
{ p!V>XY'N^  
try{ Z,;cCxE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ror|R@;y  
output.writeInt(nStartPos.length); %Lrd6i_j  
for(int i=0;i<nStartPos.length;i++) Enq|Y$qm  
{ J5[~LZKW  
// output.writeLong(nPos); r-IVb&uF b  
output.writeLong(fileSplitterFetch.nStartPos); qXW})(  
output.writeLong(fileSplitterFetch.nEndPos); J.+BD\pa  
} 8; R|  
output.close(); z6~ H:k1G%  
} XJ+6FT/qss  
catch(IOException e){e.printStackTrace ();} %77p5ctW  
catch(Exception e){e.printStackTrace ();} $ RwB_F  
} oi&Wo'DX  
 oM1 6C|  
(zYy }g#n  
//读取保存的下载信息(文件指针位置) NLe}Jqp  
private void read_nPos() %=<IGce  
{ (9mMkU=  
try{ Y'3}G<'%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); asgF1?r  
int nCount = input.readInt(); ]G}B 0u3  
nStartPos = new long[nCount]; 's!-80sd  
nEndPos = new long[nCount]; ExXM:1 e26  
for(int i=0;i<nStartPos.length;i++) 0l#)fJo  
{ RF!1oZ  
nStartPos = input.readLong(); 9H]Lpi^OH  
nEndPos = input.readLong(); =}fd6ea(o  
} @C-dG7U.P  
input.close(); Dli^2hD  
} Ld,5iBiO:  
catch(IOException e){e.printStackTrace ();} Hv<'dt$|  
catch(Exception e){e.printStackTrace ();} 5;TuVU.8Q  
} x2#qg>`l  
XfzVcap  
PaCzr5!~f  
private void processErrorCode(int nErrorCode) _0 snAt^iC  
{ >(tn"2  
System.err.println("Error Code : " + nErrorCode); B)h>8 {  
} Uo_tUp_Q  
]Lqt( c  
W:VP1 :  
//停止文件下载 8{Fm[ %"  
public void siteStop() t.hm9}UQ  
{ Vjm_F!S  
bStop = true; M}"r#Plq  
for(int i=0;i<nStartPos.length;i++) 3%<C<(  
fileSplitterFetch.splitterStop(); MuEy>dl  
L1)@z8]   
) I@L+  
} cQZ652F9  
} $\Tkhq<  
//负责部分文件的抓取 VnJMmMM  
**FileSplitterFetch.java "x&C5l}n  
*/ z&3]%t `C  
package NetFox; 1(GHCxA8G  
A~{f/%8D  
AzpV4(:an.  
import java.io.*; $ 'QdFkOr  
import java.net.*; ]&i+!$N_  
7TX,T|>9  
VLg EX4  
public class FileSplitterFetch extends Thread { *Wb=WM-.  
)yb+M ez  
M`,XyIn  
String sURL; //File URL ;ggy5?>Qu  
long nStartPos; //File Snippet Start Position x@cN3O  
long nEndPos; //File Snippet End Position H.O(*Q=  
int nThreadID; //Thread's ID [ij,RE7,T  
boolean bDownOver = false; //Downing is over g>7Y~_}  
boolean bStop = false; //Stop identical 22KI]$D#f  
FileAccessI fileAccessI = null; //File Access interface jV7&Y.$zF]  
gw3NS8 A+  
Yi rC*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eE/%6g  
{ +ydm,aKk  
this.sURL = sURL; WA.\*Nqze  
this.nStartPos = nStart; 4W\,y_Q o  
this.nEndPos = nEnd; ]Bb7(JX  
nThreadID = id; mKg@W;0ML  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 02]xJo  
} JFqf;3R  
,i ++fOnQ  
L,-u.vV  
public void run() /'>;JF  
{ !Zwf 397  
while(nStartPos < nEndPos && !bStop) ]~a_d)  
{ X#+`e+Df  
h[ 6hM^n  
H] qq ~bO[  
try{ {B yn{?w  
URL url = new URL(sURL); '%3{jc-}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LnMwx#^*  
httpConnection.setRequestProperty("User-Agent","NetFox"); <qiICb)~  
String sProperty = "bytes="+nStartPos+"-"; DB&SOe  
httpConnection.setRequestProperty("RANGE",sProperty); hD 46@  
Utility.log(sProperty); ! VRI_c  
g^o_\ hp  
`.k5v7!o  
InputStream input = httpConnection.getInputStream(); o|2 87S|$  
//logResponseHead(httpConnection); 5&4F,v[zp  
yCM{M  
4&}\BU*  
byte[] b = new byte[1024]; dB|Te"6  
int nRead; a0zG(7.D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NR/-m7#-  
{ |Odu4 Q  
nStartPos += fileAccessI.write(b,0,nRead); +6%7C C6  
//if(nThreadID == 1) l6B.6 '4)w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T~Yg5J  
} Cals?u#U=  
B {i&~k  
&9ki O  
Utility.log("Thread " + nThreadID + " is over!"); rqvU8T7A  
bDownOver = true; 6dT|;koWbm  
//nPos = fileAccessI.write (b,0,nRead); f Lk"tW  
} ~{ .,8jE  
catch(Exception e){e.printStackTrace ();} [w%#<5h  
} W:ixzpQ  
} P6OM)>C  
<J#R3{  
gv` h-b  
//打印回应的头信息 |z7dRDU}]  
public void logResponseHead(HttpURLConnection con) c=t*I0-OVS  
{ Z oTNm  
for(int i=1;;i++) urxqek  
{ w?ai,Pw  
String header=con.getHeaderFieldKey(i); ~&[u]u[  
if(header!=null) V/UB9)i+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;2W2MZ!TF  
Utility.log(header+" : "+con.getHeaderField(header)); RUrymkHFB  
else $u,G Vq~  
break; "=`~iXT{e  
} 0e9A+&r  
} w:tGPort  
DM/hcY$MW  
Y<ElJ>A2I  
public void splitterStop() zlX! xqHj  
{ p[P[#IeL  
bStop = true; 7jZrU|:yu(  
} )% |r>{  
&kq7gCd  
bf^ly6ml  
} uf0^E3H  
V9$-twhu  
:A$wX$H01  
/* M7H~;S\3IM  
**FileAccess.java xucIjPi]  
*//文件访问(定位,写) .%hQJ{vf-^  
package NetFox; wR1K8b".DC  
import java.io.*; wG6FS  
k*9%8yi_ U  
= P8~n2V  
public class FileAccessI implements Serializable{ <\xQ7|e  
I_L;T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $U mE  
RandomAccessFile oSavedFile; |x[$3R1@  
long nPos; h&'J+b  
|=OpzCs  
b2%blQgo  
public FileAccessI() throws IOException {G]`1Q1DR  
{ &*c'uN w  
this("",0); Bzm. X=U:  
} 8I {56$  
H!^C2  
u> In(7\  
public FileAccessI(String sName,long nPos) throws IOException ^"/Dih\_  
{ 9/Q S0  
oSavedFile = new RandomAccessFile(sName,"rw"); GfQ^@Tl  
this.nPos = nPos; !%)L&W_  
oSavedFile.seek(nPos); ]LY^9eK)>{  
} V'$oTZ`  
m4\g o  
oYGUjI  
public synchronized int write(byte[] b,int nStart,int nLen) )da:&F -  
{ t)`+d=P   
int n = -1; =z']s4  
try{ i!ds{`d  
oSavedFile.write(b,nStart,nLen); z'v9j_\  
n = nLen; pJ$(ozV  
} jS}'cm-  
catch(IOException e) aliQ6_  
{ FL~9</  
e.printStackTrace (); !}C4{Bgt*  
} _fe0,  
CYMM*4#  
I[a%a!QO  
return n; [j1^$n 8V  
} mKMGdN~  
|4LQ\'N&  
Xd5! Ti}  
} &?fvt  
c[6zX#{`  
lP-kZA!  
/* orK+B4  
**SiteInfoBean.java SSo~.)J  
*/ TosPk(o(  
package NetFox; {!>E9Px  
=54Vs8.  
)OS>9 kFH  
public class SiteInfoBean { C!oksI  
Udg & eEF  
YGi/]^Nba  
private String sSiteURL; //Site's URL B1up^(?  
private String sFilePath; //Saved File's Path o4U]lK$  
private String sFileName; //Saved File's Name 0fZ:")&4,  
private int nSplitter; //Count of Splited Downloading File a'o}u,e5  
,OFq'}q  
w@4t$bd7  
public SiteInfoBean() oT$(<$&<  
{//nSplitter的缺省值为5 jw2_!D  
//default value of nSplitter is 5 lsN /$ M|}  
this("","","",5); ]Sk#a-^~  
} | 3hT{  
$a)J CErN  
hG< a  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :K!GR  
{ (0Zrfu^  
sSiteURL= sURL; `,hW;p>-  
sFilePath = sPath; 5>0\e_V  
sFileName = sName; 0]/,m4a#n  
this.nSplitter = nSpiltter; 5? S{W  
&T5f H!?4  
[]sB^UT  
} s,{RP0|  
Y8{T.\%\+  
>}xAg7\^  
public String getSSiteURL() w50.gr7  
{ I%.jc2kK  
return sSiteURL; & bp#1KR)  
} ~m009  
f]{1ZU%4  
/7!_un9  
public void setSSiteURL(String value) >;T$#LZ  
{ "P>$=X~Zi  
sSiteURL = value; ym-lT|>Z  
} YqK+F=0  
-PIA;#Gs  
HMl!?%%  
public String getSFilePath() )M&I)In'  
{ W o<PmSt9i  
return sFilePath; ir( -$*J  
} S&;T_^|  
{Zd)U "  
. x\/XlM  
public void setSFilePath(String value) P'F Pe55F  
{ ;p?42rCIcl  
sFilePath = value; BWqik_  
} [MSDk"o&  
ZEXj|wC  
+8?R+0P  
public String getSFileName() o`JlXuG?o  
{ vfk7J5y  
return sFileName; c,{&  
} sM);gI14  
+aXMHT"U  
=DQdPA\K  
public void setSFileName(String value) ly[\mGr  
{ wh7i G8jCz  
sFileName = value; YFC0KU  
} M+;!]tbc3  
Q8M:7#ySji  
w|K(>5nz  
public int getNSplitter() 5Tcl<Y6l  
{ [TpA26#TTO  
return nSplitter; tDuUAI54  
} [E..VesrM  
xC=3|,U  
E@'CU9Fo  
public void setNSplitter(int nCount) d=.n|rS4 W  
{ jN5} 2 p*  
nSplitter = nCount; ;OT#V,}r  
}  8E.5k@  
} *1 J#Mdd  
->RF`SQu  
nEa'e5 lg  
/* +0JH"L5!  
**Utility.java Pv/%s) &y&  
*/ )0 42?emn  
package NetFox; pRDON)$  
leX7(Y;!a7  
GakmROZ@9  
public class Utility { qQ?,|4)y  
*BP\6"X  
o to wvm  
public Utility() z wniS6R1  
{ k8t Na@H  
0W<nE[U  
hD9' `SQ  
} X&;]  
$ uIwRG <  
//线程睡眠 BSq;R G(  
public static void sleep(int nSecond) ys"mP* wD  
{ x:&L?eOT  
try{  c+G:@%  
Thread.sleep(nSecond); a_}BTkfHa  
} VES4x%r=  
catch(Exception e) D/%b@Ls2ze  
{ IZ(CRKCGBl  
e.printStackTrace (); $M8>SLd  
} dBD4ogo1  
} \qK}(xq[  
+%cr?g  
//日志 f >, Qhl  
public static void log(String sMsg) *M\i4FO8  
{ l7r N  
System.err.println(sMsg); ]@j"0F/`  
} =[tls^  
QWQ6j#`  
X0r#,u  
public static void log(int sMsg) Stp*JU  
{ { P\8g8  
System.err.println(sMsg); r+W 8m?oi  
} 9rvxp;  
} KohQ6q  
5yN8%_)T  
eABdy e  
/* Xy(SzJ %  
**TestMethod.java D*2p  
*/ $d"f/bRWy  
package NetFox; 1 069]  
qKb- aP-  
rsIPI69qJ.  
public class TestMethod { C,e$g  
,+5VeRyrV  
#+DmH  
public TestMethod() (A<sFw?  
{ ///xx/weblogic60b2_win.exe 0tm "kzy  
try{ 2KNKdV3NK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HBf8!\0|/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~9ls~$+*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F8r455_W"  
fileFetch.start(); ?0)XS<  
} sZP3xh[B  
catch(Exception e){e.printStackTrace ();} `F`'b)  
W/F4wEODY  
^1& LHrT  
} k2,oyUT=S  
Dqcu$ V]  
..]X<  
public static void main(String[] args) qYiK bzy  
{ XTXo xZ#w  
new TestMethod(); N(/<qv  
} :W<,iqSCm  
} ^3@a0J=F  
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