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http断点续传简单实现(java)

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/* =AgY8cF!sl  
**SiteFileFetch.java 8H;TPa  
*/ 'U1r}.+b>  
package NetFox; D:n0d fPU  
import java.io.*; wO8^|Yf  
import java.net.*; <@*mFq0,  
9-Ib+/R0  
lS?f?n^  
public class SiteFileFetch extends Thread { ip>dHj z  
d /t'N-m  
7Fy^K;V"  
SiteInfoBean siteInfoBean = null; //文件信息Bean D>G&aQ  
long[] nStartPos; //开始位置 _rs#h)  
long[] nEndPos; //结束位置 TlBLG.-^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /cI]Z^&  
long nFileLength; //文件长度  k[vn:  
boolean bFirst = true; //是否第一次取文件 v Z]gb$  
boolean bStop = false; //停止标志 {B\.8)&8  
File tmpFile; //文件下载的临时信息 &-cI|  
DataOutputStream output; //输出到文件的输出流 MIR17%G  
Q&QR{?PMD  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 7/*; rT  
public SiteFileFetch(SiteInfoBean bean) throws IOException oAvJ"JH@i  
{ oR-_=U^  
siteInfoBean = bean; t9K.Jc0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zv0RrF^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2tWUBt\,g  
if(tmpFile.exists ()) N_gjOE`x5  
{ FswFY7 8  
bFirst = false; l}O`cC  
read_nPos(); yaX,s 4p  
} /$9/,5|EA  
else n]j(tP  
{ `Z@wWs  
nStartPos = new long[bean.getNSplitter()]; ,E>VYkoA  
nEndPos = new long[bean.getNSplitter()]; |(P>'fat-p  
} e#zGLxa  
klch!m=d  
J2 5>t^  
(nE$};c<b2  
} wfZ 'T#1  
fA 3  
yS3x))  
public void run() fmSw%r|pT  
{ \C<rg|  
//获得文件长度 }`_2fJ6  
//分割文件 "lz!'~im  
//实例FileSplitterFetch *Lh0E/5  
//启动FileSplitterFetch线程 "(C }Dn#  
//等待子线程返回 e<C5}#wt  
try{ n[iil$VKh  
if(bFirst) 5;|9bWH  
{ oO UVU}H  
nFileLength = getFileSize(); rg'? ?rq  
if(nFileLength == -1) 5#d(_  
{ Me`"@{r|#  
System.err.println("File Length is not known!"); CZa9hsM  
} r?[mn^Bo5  
else if(nFileLength == -2) tICxAp:  
{ '[juPI(!  
System.err.println("File is not access!"); d3{Zhn@  
} be764do  
else Eui;2P~  
{ 71 A{"  
for(int i=0;i<nStartPos.length;i++) d&ZwVF!  
{ 4\$Ze0tv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /60[T@Mz  
} $PTedJ}*Y  
for(int i=0;i<nEndPos.length-1;i++) 7H[+iS0  
{ g Sa,A  
nEndPos = nStartPos[i+1]; O]PfQ  
} tlcA\+%)  
nEndPos[nEndPos.length-1] = nFileLength; }6S4yepl  
} +2?0]6EQ  
} jOuv\$  
4u(}eE f7  
96PVn  
//启动子线程 1L9^N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4p-$5Fk8}  
for(int i=0;i<nStartPos.length;i++) W*s`1O>  
{ 4]+ ^K`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6F(yH4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7"[lWC!As5  
nStartPos,nEndPos,i); m9q%l_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nQP0<_S  
fileSplitterFetch.start(); .(hb8 rCM  
} &x3"Rq_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <r\)hx0ov  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); siG?Sd_2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %fyb?6?Y  
nEndPos = " + nFileLength); xH f9N?  
// fileSplitterFetch[nPos.length-1].start(); sEj:%`l|  
7<tqT @c  
b\+|g9Tm  
//等待子线程结束 cj8r-Vu/N  
//int count = 0; lLJb3[ e.  
//是否结束while循环 XWvs~Xw@  
boolean breakWhile = false; 8bysg9H0  
}3*h`(Bv7  
.*f;v4!  
while(!bStop) >3kR~:;  
{ bF Vd v&  
write_nPos(); s<dD>SU  
Utility.sleep(500); RSi0IfG5  
breakWhile = true; y k5P/H)  
y,r`8  
,,Db:4qfjD  
for(int i=0;i<nStartPos.length;i++) U'lD|R,g  
{ ,yqzk.  
if(!fileSplitterFetch.bDownOver) njX:[_&  
{ g SwG=e\  
breakWhile = false; QbNv+Eu5  
break; jQr~@15J#  
} $XI<s$P%(%  
} >4VU  
if(breakWhile) ljis3{kn""  
break; bOFLI#p&  
2l SM`cw  
FEZ6X  
//count++; KGWENX_U  
//if(count>4) q%'ovX(dm  
// siteStop(); 395o[YZx*  
} $ i&$ZdX  
5]Ra?rF  
IL=v[)en4  
System.err.println("文件下载结束!"); Gzfb|9 ,q  
} R] [M_ r  
catch(Exception e){e.printStackTrace ();} (g)@wNBW  
} e-')SB  
'H'+6   
h@~X*yLKh  
//获得文件长度 iR_Syk`G*A  
public long getFileSize() ICTtubjV"  
{ _l,Z38  
int nFileLength = -1; P3yiJ|vP  
try{ StDmJ]  
URL url = new URL(siteInfoBean.getSSiteURL()); dbuOiZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &`Di cfD  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~76.S  
C~;0A!@]Y  
bsP ;  
int responseCode=httpConnection.getResponseCode(); '=~y'nPG7  
if(responseCode>=400) 7gMtnwT  
{ KVcZ@0[S  
processErrorCode(responseCode); CU;nrd"  
return -2; //-2 represent access is error z-gwNE{  
} &0eB@8{N  
 ke#;1  
4@V] zfu^Q  
String sHeader; 5p|@)  
}>w  
Ntn md  
for(int i=1;;i++) 4QN;o%,  
{  b:QFD|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %1@<),  
//Utility.log(in.readLine()); lp}WBd+  
sHeader=httpConnection.getHeaderFieldKey(i); ^'fKey`  
if(sHeader!=null) oGVSy`ku  
{ -h@0 1  
if(sHeader.equals("Content-Length")) :|M/+XPu  
{ <ut DZ#k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L_|uB  
break; 7L+X\oaB  
} BXo|CITso  
} w&"w"  
else =.X?LWKY  
break; h*KHEg"+  
} a-E-hX2  
} w~U`+2a3  
catch(IOException e){e.printStackTrace ();} rc$!$~|I3Z  
catch(Exception e){e.printStackTrace ();} 6}T%m?/}  
W|#ev*'F  
euhZ4+  
Utility.log(nFileLength); cXY'>N  
=[K)<5,@  
]pV1T  
return nFileLength; =b!J)]  
} ww($0A`ek  
qZJ*J+  
Z&w^9;30P  
//保存下载信息(文件指针位置) kN j3!u$  
private void write_nPos() V"H 7zx  
{ NoO+xLHw8  
try{ 1mJ_I|98  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uvDoo6'  
output.writeInt(nStartPos.length); 1bJ]3\  
for(int i=0;i<nStartPos.length;i++) ~snF20  
{ PS(j)I3  
// output.writeLong(nPos); -?nT mzRc  
output.writeLong(fileSplitterFetch.nStartPos); ewrWSffe  
output.writeLong(fileSplitterFetch.nEndPos); EO&ACG  
} tt ]V$V  
output.close(); 0['"m^l0S  
} U('<iw,Yy  
catch(IOException e){e.printStackTrace ();} R5eB,FN  
catch(Exception e){e.printStackTrace ();} -t 6R!ZI  
} p,iCM?[|  
zf,%BI[Hr  
3rdfg  
//读取保存的下载信息(文件指针位置) UY-IHz;&O-  
private void read_nPos() B`B%:#  
{ %i-lx`U  
try{ " q^#39i?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S[ ~O')  
int nCount = input.readInt(); cN WcNMm  
nStartPos = new long[nCount]; =/g$bZ  
nEndPos = new long[nCount]; BO4 K#H7  
for(int i=0;i<nStartPos.length;i++) 9J7J/]7f  
{ 'K3 s4x($  
nStartPos = input.readLong(); J`q}Ry;   
nEndPos = input.readLong(); Yv>BOK  
} 2]} Uov  
input.close(); +&7Kk9^  
} ,=Nw(GI  
catch(IOException e){e.printStackTrace ();} F[CT l3X  
catch(Exception e){e.printStackTrace ();} k9) u 3  
} i6md fp|k  
Yxd{&47  
'dc+M9u)_q  
private void processErrorCode(int nErrorCode) Q*:h/Lhb&  
{ vV.~76AD5  
System.err.println("Error Code : " + nErrorCode); >4/L-y+  
} :@ E1Pun?  
|jk-@ Z*  
&QTeGn  
//停止文件下载 43>9)t  
public void siteStop() Pc(n@'m~  
{ rMHQzQ0%  
bStop = true; ?7uK P}1|  
for(int i=0;i<nStartPos.length;i++) Aw4?y[{H  
fileSplitterFetch.splitterStop(); Fi'M"^:r {  
z]c,} Q  
OwA~(  
} (9}eF)+O  
}  @yt 2_  
//负责部分文件的抓取 RM&H!E<#  
**FileSplitterFetch.java Y=a v8Y|`  
*/ ;tp]^iB#  
package NetFox; sLG>>d3R1  
'B3Wza.  
y~ _za(k  
import java.io.*; q#99iiG1  
import java.net.*; JOrELrMx  
5@czK*5  
)@]6=*%  
public class FileSplitterFetch extends Thread { ])V2}gH  
*:\:5*SY  
"Ap$ Jl B  
String sURL; //File URL vm\wO._  
long nStartPos; //File Snippet Start Position (Pv`L  
long nEndPos; //File Snippet End Position xHJ8?bD p  
int nThreadID; //Thread's ID Q1`<fD  
boolean bDownOver = false; //Downing is over 6F*-qb3  
boolean bStop = false; //Stop identical heL$2dZ5H  
FileAccessI fileAccessI = null; //File Access interface Tr8AG>  
2(m85/Hr\;  
R CBf;$O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException : 8^M5}  
{ _8Nw D_"  
this.sURL = sURL; 1Xy8|OFc[  
this.nStartPos = nStart; M3Khc#5S(  
this.nEndPos = nEnd; P +dA~2k  
nThreadID = id; Y=vVxVI\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B;Xoa,  
} I tI0x  
+@emX$cFV  
ME$2P!o  
public void run() q=6Cc9FN  
{ yo\N[h7  
while(nStartPos < nEndPos && !bStop) EBoGJ_l  
{ b , juF2  
M{?zvq?d  
DX}B0B  
try{ TGU:(J'^  
URL url = new URL(sURL); R_Zv'y6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w9RF2J  
httpConnection.setRequestProperty("User-Agent","NetFox"); .dx 4,|6  
String sProperty = "bytes="+nStartPos+"-"; %G;0T;0L  
httpConnection.setRequestProperty("RANGE",sProperty); _wf5%(~b  
Utility.log(sProperty); j G-  
I|,pE**T  
Y5dD|]F|  
InputStream input = httpConnection.getInputStream(); ]} 61vV  
//logResponseHead(httpConnection); q$r&4s)To  
sl/=g   
z Yw;q3"  
byte[] b = new byte[1024]; U;xu/xDRi  
int nRead; Y^52~[w~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q#P$'7"  
{ v(DwU!  
nStartPos += fileAccessI.write(b,0,nRead); I eG=J4:*  
//if(nThreadID == 1) yND"bF9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %35L=d[  
} '_:(oAi,C  
B*\$ /bk,  
!FTNmyM~F  
Utility.log("Thread " + nThreadID + " is over!"); 9-0<*)"b>  
bDownOver = true; :e*DTVv8  
//nPos = fileAccessI.write (b,0,nRead); \K}-I  
} 7vn%kW=$  
catch(Exception e){e.printStackTrace ();} ~C&*.ZR  
} 9O;cJ)tXY  
} qG<7hr@x]  
t\h$&[[l'z  
Sw~(uH_l  
//打印回应的头信息 ^ eQFg>  
public void logResponseHead(HttpURLConnection con) '77~{jy  
{ |]`hXr  
for(int i=1;;i++) \(I0wEQo$  
{ @q K]JK  
String header=con.getHeaderFieldKey(i); 5?WYsj"  
if(header!=null) *G9sy_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xwRhs!`t1  
Utility.log(header+" : "+con.getHeaderField(header)); 5W/{h q8}}  
else -LtK8wl^  
break; m9in1RI%  
} pkJ/oT  
} 57wFf-P  
{ ;s;.  
|EKu2We*  
public void splitterStop() E<tK4?i"  
{ 0RUi\X4HI  
bStop = true; O] Y v   
} E<>*(x/\e  
A{# Nwd>  
"(v%1tGk  
} iPq &Y*  
H~noJIw#  
OS-sk!  
/* ^W~p..DF  
**FileAccess.java &(EHq  
*//文件访问(定位,写) j[I`\"  
package NetFox; aSC9&Nf;  
import java.io.*; )p<WDiX1!e  
y<pnp?x4  
As~(7?]r  
public class FileAccessI implements Serializable{ $&{ti.l  
=-NiO@5o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :_5/u|{  
RandomAccessFile oSavedFile; <3 TA>Dz  
long nPos; :_ROJ  
%f j+70  
{%C*{,#+8q  
public FileAccessI() throws IOException G?AG:%H%  
{ <A >)[u  
this("",0); |Os6V<u"  
} !d,8kG  
Qck| #tc  
u7fK1 ^O  
public FileAccessI(String sName,long nPos) throws IOException Rx7X_A}  
{ V8WFQdXc  
oSavedFile = new RandomAccessFile(sName,"rw"); uI~s8{0T6  
this.nPos = nPos; 7ER|'j  
oSavedFile.seek(nPos); G,f-.  
} UH? p]4Nz  
4[yIOs  
?WUF!Jk  
public synchronized int write(byte[] b,int nStart,int nLen) &;E5[jO^D  
{ >5hhd38  
int n = -1; (@r `$5D.b  
try{ eg/<[ A:  
oSavedFile.write(b,nStart,nLen); MP^ d}FL  
n = nLen; AH#4wPxF  
} :XG;ru%i  
catch(IOException e) ujFzJdp3k  
{ s&a1y~rv  
e.printStackTrace (); Aw5pd7qKL  
} a(IY\q[Wh  
*T`-|H*6@  
7j$Pt8$  
return n; #>[a{<;Kn  
} q5x[~]?  
5O <>mCF  
: i~W } r  
} eS+g|$cW  
~g#r6pzN-  
4dawg8K`9  
/* #3$\Iu  
**SiteInfoBean.java izgp*M,  
*/ @{hd{>K*  
package NetFox; Bc7V)Y K  
G7GZDi  
2)X4y"l  
public class SiteInfoBean { 7F^#o-@=J  
fu[K".  
5cJ !"  
private String sSiteURL; //Site's URL WWKvh  
private String sFilePath; //Saved File's Path ^n1%OzGK#  
private String sFileName; //Saved File's Name 0AK,&nbF  
private int nSplitter; //Count of Splited Downloading File q:\g^_!OGA  
<TGn=>u  
t_z,>,BqJ  
public SiteInfoBean() }t9.N`xu  
{//nSplitter的缺省值为5 k o;>#::  
//default value of nSplitter is 5 =U8Ek;Drp  
this("","","",5); );V2?G`/  
} S! Rc|6y%  
uhyj5u)  
O7d$YB_'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7hP<f}xL  
{ ({r*=wAP  
sSiteURL= sURL; #LlUxHv #  
sFilePath = sPath; 3_Cp%~Gi-_  
sFileName = sName; !Ucjax~  
this.nSplitter = nSpiltter; fhPkEvJ  
Sr?#wev]rn  
qfY5Ww$8  
} o+w;PP)+=  
N`@NiJ(O;  
Vd^g9  
public String getSSiteURL() E 99hlY~1:  
{ $YxBE`)d-  
return sSiteURL; (*}yjUYLZ  
} S$)*&46g  
>Y7a4~ufko  
2H71~~ c  
public void setSSiteURL(String value) KmG  
{ T>TWU:  
sSiteURL = value; ca i <,3H  
} K 0gI):  
z>sbr<doa  
@NhvnfZ  
public String getSFilePath() 6E(Qx~i L  
{ Y8M]Lwj  
return sFilePath; }En  
} !+>v[(OzM  
qm/Q65>E  
:NJ_n6E  
public void setSFilePath(String value) =_$Qtq+h  
{ ,B?~-2cCz  
sFilePath = value; OsBo+fwT  
} <,o>Wx*1C  
W} WI; cI  
Lbe\@S   
public String getSFileName() .2d9?p3Y  
{ :w}{$v}#D;  
return sFileName; T134ZXqqz  
} V7#v6!7A@  
4BnSqwa_  
EA ]+vq  
public void setSFileName(String value) KT]Pw\y5  
{ ? WJ> p  
sFileName = value; ^` un'5Vk  
} S$KFf=0  
>U F  
f#+el y  
public int getNSplitter() 3bO(?l`3h  
{ BA\/YW @  
return nSplitter; u]}s)SmDk  
} l/;X?g5+  
B8E'ddUw  
4iSa7YqhBT  
public void setNSplitter(int nCount) n]8<DX99Q0  
{ %X#zj"  
nSplitter = nCount; ~l;[@jsw F  
} f{SB1M   
} )`^p%k  
6'\6OsH  
dJ"iEb|4  
/* hW{j\@R  
**Utility.java *s@Qtgu  
*/ U qG .:@T  
package NetFox; +`3!I  
V_plq6z  
P[s8JDqu  
public class Utility { fw ,\DFHO  
Aw&tP[N[  
U,nEbKJgk  
public Utility()  KWLbD#  
{ v<Bynd-  
l5L.5 $N  
VfT*7_  
} ~]ZpA-*@Ut  
N !TW!  
//线程睡眠 (O0Urm  
public static void sleep(int nSecond) R|i/lEq  
{ Da"j E  
try{ <n3!{w3<  
Thread.sleep(nSecond); C6rg<tCH  
} NcY608C  
catch(Exception e) B"%{i-v>**  
{ AT5aDEb^^  
e.printStackTrace (); c-.t>r &  
} $-[CG7VgX%  
} 1S@vGq}  
JxyB(  
//日志 q^6+!&"  
public static void log(String sMsg) A*W) bZs.  
{ 6e7{Iy  
System.err.println(sMsg); DxJX+.9K9  
} 'Ei;^Y 1e  
fS^!ZPe1  
zt^48~ry  
public static void log(int sMsg) ~|<m,)!  
{ .*elggM  
System.err.println(sMsg); 2h?uNW(0Q  
} 610D% F  
} WxF:~{  
aL\nT XakX  
j <o3JV  
/* p !s}=wI `  
**TestMethod.java ! !PYP'e  
*/ znJ'iV f  
package NetFox; k}~O}~-  
1bGopi/  
GguFo+YeZ  
public class TestMethod { 52o x`t|  
"s\L~R.&  
3"F`ZJ]=  
public TestMethod() $+7`Dy!  
{ ///xx/weblogic60b2_win.exe 86z]<p (  
try{ $8a(veXd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *b]; |n{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iOG[>u0h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jM\*A#Jo5  
fileFetch.start(); vVL@K,q  
} a ^%"7Ri  
catch(Exception e){e.printStackTrace ();} [e1S^pI  
s|D>-  
W\18{mbuy  
} (ND4Q[*6  
-j&Tc` j_  
['ksP-=  
public static void main(String[] args) KoS*0U<g6  
{ >2By +/!X  
new TestMethod(); cHa]xmy%r'  
} t=xOQ 8  
} *28pRvY:b  
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