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http断点续传简单实现(java)

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/* 'y< t/qo  
**SiteFileFetch.java v: giZxR  
*/ Wux0RF&  
package NetFox; lK "' nLL  
import java.io.*; :,jPNuOA  
import java.net.*; 9U&~(;  
=[s8q2V  
K4_~ruhr  
public class SiteFileFetch extends Thread { vf6`s\6  
FMoJ"6Q  
Ih(:HFRMq6  
SiteInfoBean siteInfoBean = null; //文件信息Bean $|rCrak;  
long[] nStartPos; //开始位置 [+y &HNf  
long[] nEndPos; //结束位置 fBf]4@{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C?8PT/  
long nFileLength; //文件长度 NS h%t+XU]  
boolean bFirst = true; //是否第一次取文件 3T"2S[gT  
boolean bStop = false; //停止标志 VIb;96$Or  
File tmpFile; //文件下载的临时信息 92s4u3 L;  
DataOutputStream output; //输出到文件的输出流 BO[+E' 2  
j'\>Nn+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !&qx7eOSpP  
public SiteFileFetch(SiteInfoBean bean) throws IOException &Q2NU$  
{ 9*BoYFw92*  
siteInfoBean = bean; pi|\0lH6W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t#a.}Jl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cZ6?P`X  
if(tmpFile.exists ()) NAJ '><2  
{ f+{c1fb>s  
bFirst = false; a:=q8Qy  
read_nPos(); $[)6H7!U)  
} ThjUiuWe  
else X";TZk  
{ _2wAaJvA  
nStartPos = new long[bean.getNSplitter()]; tX@ 0:RX%  
nEndPos = new long[bean.getNSplitter()]; ]^Sd9ba  
} th5 X?so  
0Ulxp  
5P-K *C&  
@m5O{[euj<  
} (}9cD^F0n  
$$k7_rs  
F(J\ctha  
public void run()  -PcS(  
{ s[Y)d>~\$=  
//获得文件长度 mYntU^4f  
//分割文件 _TtX`b_Z  
//实例FileSplitterFetch -b].SG5S  
//启动FileSplitterFetch线程 \El|U#$u'  
//等待子线程返回 YI L'YNH  
try{ <sm#D"GpP  
if(bFirst) $5ZR [\$  
{ eL<m.06cfY  
nFileLength = getFileSize(); 5T~3$kuO  
if(nFileLength == -1) s;vWR^Ll  
{ 98X!uh'  
System.err.println("File Length is not known!"); ?lu_}t]  
} d-9uv|SJ  
else if(nFileLength == -2) kEp.0wL'  
{ X(4s;i  
System.err.println("File is not access!"); <]Ij(+J;  
} h=uiC&B  
else _cW_u?0X:  
{ GwTT+  
for(int i=0;i<nStartPos.length;i++) ^`l"'6  
{ 8dV.nO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l\q*%'Pe  
} 6"BtfQ")  
for(int i=0;i<nEndPos.length-1;i++) Q&oC]u(="&  
{ j9{O0[v  
nEndPos = nStartPos[i+1]; ^>3tYg&7  
} |z.Gh1GCy  
nEndPos[nEndPos.length-1] = nFileLength; $ \? N<W  
} l[tY,Y:4qO  
} Dm7Y#)%8  
5LDQ^n  
6H(fk1E  
//启动子线程 Xg|8".B)A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D+bB G  
for(int i=0;i<nStartPos.length;i++) Nr> c'TH  
{ %4bO_vb<9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LXBbz;vYl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #JK;& Dg!  
nStartPos,nEndPos,i); ;k9 ?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yd7lcb [  
fileSplitterFetch.start(); p:DL:^zx  
} Y}AmX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3!i. Fmo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Gg 7Wm L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jA20c(O  
nEndPos = " + nFileLength); y0/WA4,  
// fileSplitterFetch[nPos.length-1].start(); lcu("^{3  
FQ ;4'B^k]  
BNAguAxWo  
//等待子线程结束 #E- VW  
//int count = 0; 1x~%Ydy  
//是否结束while循环 KzEuPJ?  
boolean breakWhile = false; bYwI==3  
zvek2\*rO  
Q'n(^tbL  
while(!bStop) 4+ASw N9  
{ oUW )H  
write_nPos(); nz,Mqol  
Utility.sleep(500); >i^y;5  
breakWhile = true; -X"5G  
tYI ]LL  
$nUd\B$.=  
for(int i=0;i<nStartPos.length;i++) 6{JR0  
{ k#1`  
if(!fileSplitterFetch.bDownOver) *u|lmALs  
{ >P6^k!R1y  
breakWhile = false; /'8*aUa  
break; Uq<a22t@  
} )GiFkG  
} Y9IJ   
if(breakWhile) Cm,*bgX  
break;  ltCwns  
%8}WX@SB  
ua]\xBWx  
//count++; (SgEt  
//if(count>4) \Dvl%:8   
// siteStop(); /0 B07B  
} W~XV  
4kW 30Ma  
D..{|29,:  
System.err.println("文件下载结束!"); c,#~L7  
} J~_L4* Jw  
catch(Exception e){e.printStackTrace ();} }m=t zHB*  
} p56KS5duI.  
)bB"12Z|8  
g|&.v2 '  
//获得文件长度 J8sJ~FnUj  
public long getFileSize() l _kg3e4  
{ u4b3bH9U  
int nFileLength = -1; LY@1@O2@  
try{ hj^G} 4  
URL url = new URL(siteInfoBean.getSSiteURL()); E5,%J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s)=!2AY  
httpConnection.setRequestProperty("User-Agent","NetFox"); -Z`(? k  
6=Y3(#Ddt  
c]AKeq]  
int responseCode=httpConnection.getResponseCode(); mhHA!:Y  
if(responseCode>=400) 8! |.H p  
{ EmtDrx4!(f  
processErrorCode(responseCode); U~u6}s]:  
return -2; //-2 represent access is error >:Rt>po8|w  
} z")3_5Br  
p0}+071o%  
{#dp-5V  
String sHeader; 8k+q7  
u%+6Mp[E  
jQ.>2-;H9  
for(int i=1;;i++) !uj!  
{ 8!`7-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'Yaf\Hp  
//Utility.log(in.readLine()); B#qL$M,|  
sHeader=httpConnection.getHeaderFieldKey(i); [M7iJcwt  
if(sHeader!=null)  |0C|$2  
{ Z`-)1!  
if(sHeader.equals("Content-Length")) ({d,oU$>y  
{ d vg;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x*loACee.  
break; "W?l R4  
} x*,q Rew  
} Hm+6QgCs  
else }<5\O*kX4  
break; b:}wR*Adc  
} bik] JIM  
} dU sJv  
catch(IOException e){e.printStackTrace ();} "xvV'&lQ  
catch(Exception e){e.printStackTrace ();} sUyCAKebRr  
2-"Lxe65f  
z) ]BV=  
Utility.log(nFileLength); |!4B Wt  
s]nGpA[!  
z{D$~ ob  
return nFileLength; G:h;C].  
} 2g ?Jb5)  
)E[ Q  
 ?;ALF  
//保存下载信息(文件指针位置) 2HvTM8  
private void write_nPos() +H)!uLva B  
{ V',m $   
try{ :w {M6mM>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #GDh/t2@  
output.writeInt(nStartPos.length); /H\^l.|vk  
for(int i=0;i<nStartPos.length;i++) 8^P2GG'+-  
{ 323yAF  
// output.writeLong(nPos); *hk{q/*Qw  
output.writeLong(fileSplitterFetch.nStartPos); k2_6<v Z  
output.writeLong(fileSplitterFetch.nEndPos); MQ9M%>  
} ,z0~mN  
output.close(); vjs|!O=oH  
} gNEzlx8A  
catch(IOException e){e.printStackTrace ();} H649J)v+m  
catch(Exception e){e.printStackTrace ();} evndw>  
} ^huBqEs  
^V XXq  
n7`.<*:  
//读取保存的下载信息(文件指针位置) Sq?6R}q%  
private void read_nPos() eSvc/CU  
{ ;4S [ba1/  
try{ ?v)"%.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $X.'W\o|  
int nCount = input.readInt(); hIzPy3  
nStartPos = new long[nCount]; %~B)~|h  
nEndPos = new long[nCount]; \0*yxSg,^  
for(int i=0;i<nStartPos.length;i++) QRg"/62WCD  
{ /\3XARt  
nStartPos = input.readLong(); `F- Dd4B  
nEndPos = input.readLong(); *FLTz(T  
} T,xVQ4J?  
input.close(); fr,CH{Uq  
} VxPTh\O*[  
catch(IOException e){e.printStackTrace ();} Y00i{/a 8  
catch(Exception e){e.printStackTrace ();} bAy5/G!_R  
} ?VOs:sln  
nI|Lx`*v  
HkfSx rTgQ  
private void processErrorCode(int nErrorCode) c~0VNuN  
{ eHnei F  
System.err.println("Error Code : " + nErrorCode); "u,~yxYWl  
} 5EV8zf  
qs8K jG@  
3*2&Fw!B  
//停止文件下载 {Gb)Et]<  
public void siteStop() gk_Xu  
{ &>) `P[x  
bStop = true; A\PV@w%A i  
for(int i=0;i<nStartPos.length;i++) . f.j >  
fileSplitterFetch.splitterStop(); sxC{\iLY%  
S{"6PXzb  
g*w-"%"O  
} -%/,j)VKD  
} <-oRhi4  
//负责部分文件的抓取 (W}i287  
**FileSplitterFetch.java HZr/0I?  
*/ =DF@kR[CH"  
package NetFox;  1+i  
*2m&?,nJ  
t#D\*:Xi  
import java.io.*;  7 zP  
import java.net.*; /xrq'|r?C  
/J9T=N  
c J"]yG)=  
public class FileSplitterFetch extends Thread { d,Dg"Z  
Z#cU#)`y1  
;ijfI  
String sURL; //File URL \ \mO+N47i  
long nStartPos; //File Snippet Start Position \'^Z_6{w  
long nEndPos; //File Snippet End Position Med"dHo7  
int nThreadID; //Thread's ID n nnA,  
boolean bDownOver = false; //Downing is over *V@MAt  
boolean bStop = false; //Stop identical g9lg  
FileAccessI fileAccessI = null; //File Access interface E*T84Jh6  
T=f;n;/>  
DRmh(T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2G:{FY  
{ @SQ*/sw (c  
this.sURL = sURL; Fp|rMq  
this.nStartPos = nStart; W*/s4 N  
this.nEndPos = nEnd; n`I jG  
nThreadID = id; nO.+&kA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 - 5-SlQu  
} 3_1Io+uXk  
3xCA\*  
C;:1CK  
public void run() %ucmJ-< y#  
{ 23n8,} H,  
while(nStartPos < nEndPos && !bStop) * SON>BSF  
{ Kp=3\)&  
tL4]6u  
vM4`u5  
try{ fdH'z:Xao  
URL url = new URL(sURL); v8fZ?dx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pt|$bU7  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;Q,).@<C  
String sProperty = "bytes="+nStartPos+"-"; |s3HeY+Co  
httpConnection.setRequestProperty("RANGE",sProperty); PA-0FlV|  
Utility.log(sProperty); g7Q*KA+  
*ej o6>  
,E8>:-boL  
InputStream input = httpConnection.getInputStream(); `_{ '?II  
//logResponseHead(httpConnection); 3L!&~'.Ro  
nTtt$I@hW  
yNMwd.r[  
byte[] b = new byte[1024]; vhe Ah`u^&  
int nRead; OFAqP1o{$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {j=hQL3  
{ R^O)fL0_  
nStartPos += fileAccessI.write(b,0,nRead); LAVt/TcZS|  
//if(nThreadID == 1) ;eEtdoy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N4]6LA6x6  
} [N$_@[  
jvKaxB;e  
#&8pp8wd,}  
Utility.log("Thread " + nThreadID + " is over!"); ,HO/Q6;N  
bDownOver = true; 0v)mgrl=,  
//nPos = fileAccessI.write (b,0,nRead); {8p?we3l1  
} PH4bM  
catch(Exception e){e.printStackTrace ();} Qs[EA_  
} I EsD=  
} FEi,^V  
Pg8=  
Pc ?G^ Xol  
//打印回应的头信息 v5bb|o[{K  
public void logResponseHead(HttpURLConnection con) Hf]}OvT>Z  
{ cz~11j#  
for(int i=1;;i++) L$?~TY  
{ "=TTsxyM6P  
String header=con.getHeaderFieldKey(i); W oG  
if(header!=null) 5Fm? ,^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ( 2(;u1  
Utility.log(header+" : "+con.getHeaderField(header)); `e;Sjf<  
else .0;k|&eBD  
break; f2e$BA  
} &MLhCekY  
} |B WK"G  
WG=r? xE  
?B:wV?-`  
public void splitterStop() <;Z~ vZ]  
{ -ns a3P  
bStop = true;  X_S]8Aa  
} F7u%oLjr  
(=B7_jrl  
5*'N Q010  
} 6 FxndR;  
KFG^vmrn  
e7AI&5Eg{  
/* JV{!Ukuyp+  
**FileAccess.java t7%Bv+Uo  
*//文件访问(定位,写) c)~|#v  
package NetFox; X \ZUt >  
import java.io.*; _^$b$4)  
%ycT}Lu  
\V\ET  
public class FileAccessI implements Serializable{ |}Z"|-Z  
QN5N h s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AQGE(%X  
RandomAccessFile oSavedFile; 5fv6RQD  
long nPos; =umS^fJ5`  
2*E<G|-F  
A^7Zy79  
public FileAccessI() throws IOException Ev ,8?  
{ Ekp 0.c8:  
this("",0); 4nXS9RiF2  
} :iiTz$yk  
bvvx(?!  
:WTvP$R  
public FileAccessI(String sName,long nPos) throws IOException !H.lVA  
{ Rzj!~`&N  
oSavedFile = new RandomAccessFile(sName,"rw"); I=I%e3GEm  
this.nPos = nPos; @D{[Hj`<  
oSavedFile.seek(nPos); r/:'}os;  
} oK[,xqyA  
Y0'^S<ox  
gvt4'kp  
public synchronized int write(byte[] b,int nStart,int nLen) }+3~y'k  
{ @&> +`kgU-  
int n = -1; Ki\jiflc7  
try{ ( ~o+pp!  
oSavedFile.write(b,nStart,nLen); 'm ((G4  
n = nLen; *Y?]="8c#;  
} ]c+'SJQ  
catch(IOException e) >u[ln@ l  
{ </Lqk3S-!  
e.printStackTrace (); hZG{"O!2 s  
} P3>2=qK"E(  
8\_,Y ji  
^<b.j.$<z  
return n; 0+h?Bk  
} %uMsXa  
y[eNM6p  
Y^f|}YO%y  
} K|!)<6ZsG7  
P1jkoJ  
V!!'S h  
/* _Y~?.hs^  
**SiteInfoBean.java v:b%G?o  
*/ |9JYg7<  
package NetFox; I<#kw)W!  
94/}@<d-=  
o4795r,jz  
public class SiteInfoBean { Yq.@7cJ  
,^T2hY`  
]kvE+m&p}^  
private String sSiteURL; //Site's URL '93&?  
private String sFilePath; //Saved File's Path c" HCc]  
private String sFileName; //Saved File's Name fTcRqov  
private int nSplitter; //Count of Splited Downloading File @UBp;pb}=h  
>X,6  
:eO0{JN4T  
public SiteInfoBean() v<**GW]neD  
{//nSplitter的缺省值为5 ea/6$f9^  
//default value of nSplitter is 5 JJa?"82FXZ  
this("","","",5); }%|OnEk"  
} uEY5&wX`  
{^iV<>J  
W3kilhZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a WC sLH  
{ >n62csO  
sSiteURL= sURL; kE}I b4]J  
sFilePath = sPath; Kxn=iv^Ir  
sFileName = sName; !Ai;S  
this.nSplitter = nSpiltter; yuq E  
0&@6NW&Mu  
g;1 UZE;  
} vF 1$$7k  
,$>Z= ~x*  
U/X ^  
public String getSSiteURL() s,8%;\!C  
{ !LA#c'  
return sSiteURL; ] a()siT  
} #t*c*o  
7t QiKrhp  
K(Nk|gQ  
public void setSSiteURL(String value) &/" qOZAs  
{ Ar_/9@n  
sSiteURL = value; 5irOK9hK  
} ah.Kb(d:  
`Hqu 2 '`  
%|~ UNP$  
public String getSFilePath() Y,r2m nq  
{ SQ[}]Tm;n  
return sFilePath; . j },  
} hB4.tMgZ  
bBf+z7iyc  
|m% &Qb  
public void setSFilePath(String value) g}7B0 yo  
{ O_q_O  
sFilePath = value; s&l[GKR  
} /WMLr5  
Phczf  
f.{0P-Np  
public String getSFileName() ( KrIMZ  
{ ~kga+H  
return sFileName; f\JyN@w+  
} hV%l}6yS&  
}\F>z  
)_ y{^kn3^  
public void setSFileName(String value) VI4d/2e  
{ :>5]A6Wi  
sFileName = value; OkM>  
} -llujB%;,e  
~Hq 2'  
l#Tm`br  
public int getNSplitter() r]yq #T`z  
{ ,^(T^ -  
return nSplitter; Hcpw [%(  
} K|&y?w  
TFhj]r^ {  
UTz;Sw?~hw  
public void setNSplitter(int nCount) DRnXo-Aaj  
{ -p 1arA  
nSplitter = nCount; Co M8  
} l40$}!!<  
} %2{E'^#)p-  
GZ%R fKyQ  
ETIf x)B-  
/* X$aMf &x  
**Utility.java z"-Urd^O  
*/ <5.{+!BM  
package NetFox; ` mi!"pmw  
m-:k]9I  
Oj2[(7 mO/  
public class Utility { (8{Z@  
(]JJ?aAF  
%+.]>''a  
public Utility() S'WmPv  
{ _MR2,mC  
$]vR,E  
{>:2Ff]O:  
} cIX59y#7  
`U1"WcN  
//线程睡眠 3ySnAAG  
public static void sleep(int nSecond) 3+Q6<MS q  
{ IRQ(/:]  
try{ X!@Gv:TD  
Thread.sleep(nSecond); c}Qc2D3*  
} ?E`J-ncP  
catch(Exception e) Djzb#M'm  
{ o)$sZ{` ="  
e.printStackTrace (); 67e1Y@Xu  
} ]KfHuYjM  
} ,Ya&M@^Z  
0YS*=J"7z  
//日志 q*T+8 O  
public static void log(String sMsg) cc>h=%s`  
{ -{O2Nv-]]  
System.err.println(sMsg); 6Hz=VhQrN  
} f7`y*9^  
sU8D;ML7  
\nLO.,  
public static void log(int sMsg) k_ skn3,u  
{ A4# m&o  
System.err.println(sMsg); {>i'Pb0mG|  
} ScI9.{  
} rnW i<Se  
DCNuvrZ  
ZK;HW  
/* XhS<GF%  
**TestMethod.java OTRTa{TB  
*/ 8z+ CYeV  
package NetFox; +"C0de|-  
F2u{Wzr_@  
bZ389dSn  
public class TestMethod { kqy Y:J  
Jlzhn#5c-  
}/=VnCfU  
public TestMethod() NZl0sX.:  
{ ///xx/weblogic60b2_win.exe q3;HfZ  
try{ V7&L+]!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |OC6yN *P)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); al5?w{us  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v(af aN  
fileFetch.start(); Fv3fad@x  
} #R)$nv:h?^  
catch(Exception e){e.printStackTrace ();} !6kLg1  
8\[6z0+;  
LOQEU? z  
} m\Dbb.vBvW  
# wG}T .*  
E)`+1j  
public static void main(String[] args) FuD$jsEw  
{ kweypIB  
new TestMethod(); {RzlmDStV  
} <$UY{"?  
} O|8p #  
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