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http断点续传简单实现(java)

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/* &&Ruy(&]I  
**SiteFileFetch.java [JI>e;l C:  
*/ 1b*Me'  
package NetFox; j >f  
import java.io.*; [-}LEH1[p  
import java.net.*; ' lt5|  
/[ _aw&W}Z  
9z>I&vcX  
public class SiteFileFetch extends Thread { :&*Y Io  
*d%"/l^0  
@'UbTB!  
SiteInfoBean siteInfoBean = null; //文件信息Bean YC(7k7  
long[] nStartPos; //开始位置 pW{Q%"W  
long[] nEndPos; //结束位置 O  |45r   
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SMX70T!'9  
long nFileLength; //文件长度 3$x[{\ {  
boolean bFirst = true; //是否第一次取文件 N|t!G^rP  
boolean bStop = false; //停止标志 D c5tRO  
File tmpFile; //文件下载的临时信息 >TZ 'V,  
DataOutputStream output; //输出到文件的输出流 iveJh2!#<  
(C{l4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xz!b@5DR'%  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1+wmR4o  
{ KVQ^-^  
siteInfoBean = bean; zx<:1nF,]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K?]><z{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OP:i;%@c  
if(tmpFile.exists ()) c8uFLM j  
{ 7 YS'Tf  
bFirst = false;  J+hiz3N  
read_nPos(); 04;E^,V  
} 4yOYw*X  
else (>~:1  
{ `" BFvF#  
nStartPos = new long[bean.getNSplitter()]; H&$L1CrdL  
nEndPos = new long[bean.getNSplitter()]; qUNK Dt  
} %H)^k${  
`6bIxb{  
awYnlE/Z1  
_p;>]0cc.  
} ['~E _z  
>9-$E?Mt  
l(&3s:Ud  
public void run() c lhmpu  
{ V { #8+  
//获得文件长度 G;RFY!o  
//分割文件 HpbSf1VvAf  
//实例FileSplitterFetch 2bu,_<K.  
//启动FileSplitterFetch线程 l', +l{\Z  
//等待子线程返回 <V[Qs3uo(  
try{ 1Ce7\A  
if(bFirst) Z5x&P_.x[  
{ RCZ"BxleU  
nFileLength = getFileSize(); HL8onNq  
if(nFileLength == -1) QMO.Bnek  
{ :V,agAMn  
System.err.println("File Length is not known!"); qr$h51C&  
} Sj=x.Tr\  
else if(nFileLength == -2) g|STegg  
{ sd5%Szx  
System.err.println("File is not access!"); &A/k{(.XP  
} 4F[4H\>'  
else 7'IcgTWDZy  
{ =()Vrk|uK  
for(int i=0;i<nStartPos.length;i++) V{A_\  
{ E`0mn7.t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gc<w nm|  
} B3AWJ1o  
for(int i=0;i<nEndPos.length-1;i++) {J&[JA\   
{ ;?{[vLHDL  
nEndPos = nStartPos[i+1]; !841/TRb  
} /)+V(Jlu  
nEndPos[nEndPos.length-1] = nFileLength; T`ofj7$:  
} G 6r2 "  
} j\hI, mc  
d76nyQKK  
a:v5(@8  
//启动子线程 `jHbA#sO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }}?,({T|n  
for(int i=0;i<nStartPos.length;i++) zf4\V F  
{ /Z~} dWI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b((> ?=hh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p<Oz"6_/~  
nStartPos,nEndPos,i); ax)>rP,V  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q9G\T:^ury  
fileSplitterFetch.start(); ?)-#\z=6G  
} \&8 61A;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yg@8&;bP`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {s7 3(B"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W(#u^,$e[  
nEndPos = " + nFileLength); c1Rn1M,2k  
// fileSplitterFetch[nPos.length-1].start(); ^-^ii 3G`  
634OH*6  
te[#FF3{  
//等待子线程结束 m;4qs#qCg?  
//int count = 0; rv?4S`Z,x$  
//是否结束while循环 3< 'bi}{  
boolean breakWhile = false; 1m~-q4D)V  
W9D~:>^YP  
<5 )F9.$  
while(!bStop) {D$5M/$  
{ /:Q  
write_nPos(); <jAn~=Uq[,  
Utility.sleep(500); 4 (c{%%  
breakWhile = true; mu*RXLai  
ljP<WD  
B?nw([4m  
for(int i=0;i<nStartPos.length;i++) Fp&tJ]=B.  
{ UdOO+Z_K%  
if(!fileSplitterFetch.bDownOver) >vPv 4e7&3  
{ _ ?o>i/  
breakWhile = false; g)mjw  
break; :<P3fW  
} 2MU$OI0|  
} \1ncr4  
if(breakWhile) BjyV&1tRV!  
break; $P h#pM(  
6 h%,%  
Tlm::S   
//count++; Fks #Y1rI  
//if(count>4) V(5*Dn84  
// siteStop(); }?)U`zF)7}  
} p]eVby"  
0FcG;i+  
cj\?vX\V  
System.err.println("文件下载结束!"); Ul<:Yt&nI  
} Y|!m  
catch(Exception e){e.printStackTrace ();} "wR1=&gk  
} yz<$?Gblz  
=5;tB  
=E w<s5C@  
//获得文件长度 Qv W vS9]  
public long getFileSize() Q?2Gw N  
{ 8-"D.b4  
int nFileLength = -1; ]~:WGo=_  
try{ a@S{ A5j  
URL url = new URL(siteInfoBean.getSSiteURL()); 2,6~;R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0N87G}Xu  
httpConnection.setRequestProperty("User-Agent","NetFox"); mUNAA[0 L  
XI+GWNAmJ  
Y#t9DhzFWo  
int responseCode=httpConnection.getResponseCode(); tc0(G~.N  
if(responseCode>=400) $@HW|Y  
{ eg1Mdg\a  
processErrorCode(responseCode); FnPn#Cv>*  
return -2; //-2 represent access is error U4N H9-U'  
} YuUJgt .1  
wEF"'T  
z"c,TlVN3  
String sHeader; 4YSVy2x  
5gSe=|we*p  
YU`}T<;bg  
for(int i=1;;i++) !l-Q.=yw  
{ IP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,MjlA{0  
//Utility.log(in.readLine()); c'INmc I|  
sHeader=httpConnection.getHeaderFieldKey(i); MCAWn H  
if(sHeader!=null) Dk Ef;P  
{ 0|DyYu  
if(sHeader.equals("Content-Length")) fcTg/EXn  
{ " ?Ux\)*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ti^=aB   
break; H0f]Swh0a  
} tM|/OJ7  
} t)5.m}  
else BJt]k7ku+  
break; S6<#] 6 Z  
} =h70!) Z5  
} JM7FVB  
catch(IOException e){e.printStackTrace ();}  {DD #&B  
catch(Exception e){e.printStackTrace ();} "%YVAaN  
kX2Z@ w`  
yAFt|<  
Utility.log(nFileLength); ;\(LovUy6  
*nK4XgD  
lA` qB1x  
return nFileLength; d`,z4 _  
} l{gR6U{e  
Kk,u{EA  
o)GesgxFa5  
//保存下载信息(文件指针位置) #w@FBFr@  
private void write_nPos() |\Q2L;4C  
{ ]K'OH&  
try{ 0RjFa;j  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o!lKP>  
output.writeInt(nStartPos.length); &]tm 'N25  
for(int i=0;i<nStartPos.length;i++) 3+\Zom4  
{ Z*b$&nM  
// output.writeLong(nPos); $Xh5N3  
output.writeLong(fileSplitterFetch.nStartPos); 0 ;].q*|#  
output.writeLong(fileSplitterFetch.nEndPos); !"ir}Y%  
} H.;2o(vD  
output.close(); RBfzti6  
} -Q/wW4dE=  
catch(IOException e){e.printStackTrace ();} IE3GZk+a~  
catch(Exception e){e.printStackTrace ();} Y4+ ]5;B8  
} 1(pv 3  
rp4{lHw>C/  
(f2r4Io|}  
//读取保存的下载信息(文件指针位置) _F(Np\%_  
private void read_nPos() 9C8 G(r  
{ $o. ;}  
try{ r0@s3/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k8!:`jG  
int nCount = input.readInt(); ,rjl|F* T  
nStartPos = new long[nCount]; 4M!wm]n/%5  
nEndPos = new long[nCount]; uz I-1@`  
for(int i=0;i<nStartPos.length;i++) XgyLlp;,O  
{ hE E1i  
nStartPos = input.readLong(); Z^BZH/I?  
nEndPos = input.readLong(); PC\p>6xT  
} J7sH]  
input.close(); e _(';Lk  
} -Mf-8zw8G  
catch(IOException e){e.printStackTrace ();} ^oYRB EIJH  
catch(Exception e){e.printStackTrace ();} 0|]d^bo  
} LqXVi80  
3ZN\F  
]9~Il#  
private void processErrorCode(int nErrorCode) }ik N  
{ Ct^=j@g  
System.err.println("Error Code : " + nErrorCode); )H`V\ H[0P  
} x+TdTe;p  
;n.h!wmJ}  
G^cMY$?99  
//停止文件下载 /;T tMQt  
public void siteStop() m?gGFxo  
{ YS@T Q?  
bStop = true; 1JJ1!& >  
for(int i=0;i<nStartPos.length;i++) $ce*W 9`  
fileSplitterFetch.splitterStop(); ;<GK{8  
{>PEl; ,-  
B873UN  
} PJ=|g7I  
} c^cr_ i  
//负责部分文件的抓取 `Z#':0Z  
**FileSplitterFetch.java k'*vG6!  
*/ ri-D#F)}  
package NetFox; ]rSg,Q >E  
YNl".c  
(.iwD&  
import java.io.*; ;at1|E*  
import java.net.*; o bN8+ j  
K}M lC}oIt  
|3~]XN-  
public class FileSplitterFetch extends Thread { Y DW^N] G  
%iME[| u&  
x3( ->?)D  
String sURL; //File URL BR-wL3x b  
long nStartPos; //File Snippet Start Position .S1MxZhbP  
long nEndPos; //File Snippet End Position )*R';/zaI  
int nThreadID; //Thread's ID M IyT9",Pl  
boolean bDownOver = false; //Downing is over cW_l|  
boolean bStop = false; //Stop identical q!+:zZu  
FileAccessI fileAccessI = null; //File Access interface [$ uKI,l  
k7{|\w%  
6nJQPa  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *YX5bpR?  
{ #z70:-`.[M  
this.sURL = sURL; u.G aMl4 (  
this.nStartPos = nStart; FhPCFmmUT  
this.nEndPos = nEnd; p-l FzNPc0  
nThreadID = id; ]d~{8h!G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '/9q7?[E!  
} ;;m;f^]}  
D SWmQQ  
?Ok&,\F@E  
public void run() rC]k'p2x  
{ QhLgFu  
while(nStartPos < nEndPos && !bStop) 19-V;F@;  
{ m>F:dI  
-/0aGqY  
QC!SgV  
try{ ,KD?kSIf  
URL url = new URL(sURL); z;?j+ZsdH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Fa\jVFIQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]T&d_~l   
String sProperty = "bytes="+nStartPos+"-"; Ud2Tn*QmI  
httpConnection.setRequestProperty("RANGE",sProperty); -j2y#aP  
Utility.log(sProperty); Ml;` *;  
?=^\kXc[  
q9PjQ%  
InputStream input = httpConnection.getInputStream(); l!KPgRw  
//logResponseHead(httpConnection); (+cZP&o  
NZ0?0*  
_<DOA:'v  
byte[] b = new byte[1024]; 6`G8UDK>F  
int nRead; XN>bv|*q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4e;$+! dlV  
{ %3|/t-US  
nStartPos += fileAccessI.write(b,0,nRead); 4eG\>#5  
//if(nThreadID == 1) LXsZk|IhM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AaoS & q  
} NQ;$V:s)  
7-Oa34ba+  
^ERdf2  
Utility.log("Thread " + nThreadID + " is over!"); KZ%us6  
bDownOver = true; ( ;^>G[  
//nPos = fileAccessI.write (b,0,nRead); GQJ4d-w  
} hQ!59  
catch(Exception e){e.printStackTrace ();} j_~mP>el)  
} i7v =o#  
} '*&dP"  
{ o5^nd  
I}5e{jBB  
//打印回应的头信息 ](8F]J ,  
public void logResponseHead(HttpURLConnection con) 1|!)*!hu  
{ D`mr>-Y  
for(int i=1;;i++) -meY[!"X  
{ Iu~<Y(8^q#  
String header=con.getHeaderFieldKey(i); r\FZ-gk}Q  
if(header!=null) = &?&}pVF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rly%+B `/  
Utility.log(header+" : "+con.getHeaderField(header)); HRjbGc|[  
else 3&5b!Y  
break; I{WP:]"Yf  
} D/ sYH0.V$  
} l?rLadvc  
| 5:2?S2R  
o1?-+P/  
public void splitterStop() }p)Hw2  
{ >SL mlK  
bStop = true; p >ua{}!L  
} -*~ @?  
vfvp#  
sf[|8}(  
} 42A'`io[w]  
Y'bz>@1(  
f-|zh#L  
/* j;V\~[I^u  
**FileAccess.java sLJ]N0t  
*//文件访问(定位,写) /V`SJ"  
package NetFox; L6i|5 P  
import java.io.*; :dRC$?f4  
`Mbs6AJ  
X%&7-PO  
public class FileAccessI implements Serializable{ S w%6-  
V=th-o3[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FE^/us7r  
RandomAccessFile oSavedFile; GG<0k\RN  
long nPos; U{bv|vF  
IbL'Z   
*| W*Mu  
public FileAccessI() throws IOException +F8K%.Q_  
{ kaiK1/W0;  
this("",0); njZ vi}m~  
} Yt,MXm\  
^Go,HiB  
W2fcY;HZ  
public FileAccessI(String sName,long nPos) throws IOException XqUQ{^;aI  
{ XksI.]tfj  
oSavedFile = new RandomAccessFile(sName,"rw"); v_pe=LC{-e  
this.nPos = nPos; n}e%c B  
oSavedFile.seek(nPos); .boB b<  
} _G@Z n[v  
8 l)K3;q_  
iM;Btv[|  
public synchronized int write(byte[] b,int nStart,int nLen) 2p#d  
{ i>[xN[U(  
int n = -1; `w`N5 !  
try{ 0*tnJB  
oSavedFile.write(b,nStart,nLen); MN5}}@  
n = nLen; k\;D;e{  
} wbcip8<t  
catch(IOException e) n'{jc 6&|  
{ x=L"qC9f/  
e.printStackTrace (); '[%Pdd]! E  
} 3`{;E{  
DEhR\Z!  
XOQ0(e6  
return n; f(eXny@Y  
} ';8 ,RTe  
5S!j$_(  
7-n HPDp'  
} V9}\0joM  
K@%T5M4j  
km5gO|V>m  
/* SqRM*Cf=  
**SiteInfoBean.java 8v8-5N  
*/ mwsBj)  
package NetFox; "=C~I W  
:AFU5mR4&  
KnA BFH  
public class SiteInfoBean { @NL<v-t  
2)\MxvfOh  
{ pQJ.QI  
private String sSiteURL; //Site's URL Qt{V&Z7  
private String sFilePath; //Saved File's Path `AvK8Wh<+  
private String sFileName; //Saved File's Name 5 -|7I7(G$  
private int nSplitter; //Count of Splited Downloading File "eOl(TSu/  
^E\n^D-RV  
}vOg9/[{  
public SiteInfoBean() :@P6ibcX  
{//nSplitter的缺省值为5 xoj,>[7 D  
//default value of nSplitter is 5 QGV#AID3XW  
this("","","",5); bV2a2#kj  
} :E|Jqi\  
"nfi :A1  
,X:3w3nr^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xg^%8Ls^  
{ SSla^,MHef  
sSiteURL= sURL; 2dKt}o>   
sFilePath = sPath; ^z{Xd|{"  
sFileName = sName; R[m{"2|,Lc  
this.nSplitter = nSpiltter; w6h83m 3  
qN' 3{jiPL  
7G;1n0m-T  
} <oT1&C{  
B6TE9IoSb8  
5{+2#-  
public String getSSiteURL() }:{ @nP  
{ YT'V/8US  
return sSiteURL; v?6*n >R  
} KaOXqFT=  
}Rh%bf7,  
O/ItN5B ;  
public void setSSiteURL(String value) "s]  
{ XRQ1Uh6  
sSiteURL = value; O gQ8yKfDB  
} i%<NKE;v7m  
A Y<L8  
*,:2O&P  
public String getSFilePath() RFFbS{U*  
{ 5[B)U">]  
return sFilePath; b&4JHyleF  
} OvwoU=u  
)CE]s)6+2  
 !O`j  
public void setSFilePath(String value) p< 0=. ~  
{ -EFdP]XO  
sFilePath = value; #6YpV)  
} Hf1b&8&:K  
f_LXp$n  
n/*" 2  
public String getSFileName() qa@;S,lp  
{ SDSP4W5  
return sFileName; tq~f9EvC  
} GhcH"D%-  
PZ'|)  
TJW8l[M  
public void setSFileName(String value) *HHL a  
{ [:(O`#  
sFileName = value; K re*~ "  
} eFf9T@  
5izpQ'>  
m*jE\+)=^  
public int getNSplitter() ujBm"p_|  
{ %uV,p!| )  
return nSplitter; R1Q,m  
} U,T#{  
e:4,rfF1  
hJ[keaO  
public void setNSplitter(int nCount) }1V+8'D  
{ JzCkVF$  
nSplitter = nCount; KQ6][2-  
} et/l7+/'  
} <Z_\2 YW A  
;@gI*i N"  
cL.>e=x$  
/* v^Fu/Y  
**Utility.java o%z^@Cq  
*/ RL]$"  
package NetFox; Xg1TX_3Ml  
dxZn| Y  
tP2.D:( R  
public class Utility { *&]8rm{  
IDqUiN  
WL'!M&h  
public Utility() dQ_'8 )  
{ N M),2%<  
hSAI G  
s[UV(::E  
} hR2 R  
qM 1ZCt  
//线程睡眠 aL;zN%Tw  
public static void sleep(int nSecond) 2sG1Hox  
{ ,aP5)ZN-  
try{ U Rq9:{  
Thread.sleep(nSecond); 4, Vx3QFZ  
} };"_Ku4#-  
catch(Exception e) QZ7W:%r(4  
{ Xa ;wx3]t  
e.printStackTrace (); H=WB6~8)  
} ?5lO1(  
} \SwqBw  
HpUJ_pZ  
//日志 o.|36#Fa  
public static void log(String sMsg) o>d0R w4h  
{ ?/hS1yD;  
System.err.println(sMsg); MZA%ET,l,<  
} Y:Lkh>S1Q  
i Pl/I  
zp'hA  
public static void log(int sMsg) ?;5/"/i  
{ Nknd8>Hy+  
System.err.println(sMsg); ;O,&MR{;|n  
} =)i^E9  
} |FlB#  
RhF< {U.  
yU7XX+cB7  
/* ND=JpVkvZ?  
**TestMethod.java F &5iA\  
*/ j1+I_   
package NetFox; XS^du{ai  
V8o, e  
{IBbN05 ;  
public class TestMethod { 5RO6YxQ  
).u>%4=6  
/Hm/%os  
public TestMethod() /J!hKK^k  
{ ///xx/weblogic60b2_win.exe &pz`gna  
try{ e,#5I(E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H D$`ZV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K~^o06 Y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LSXsq}  
fileFetch.start(); 5OO XCtIKf  
} ,?%Y*?v  
catch(Exception e){e.printStackTrace ();} )ytP$,r![S  
:AuKQ`c  
P&Xy6@%[Z  
} DSp~k)  
:c )R6=v  
UaQW<6+  
public static void main(String[] args) e9S*^2;  
{ \fUVWXv  
new TestMethod(); B"*PBJuOA  
} ga;t`5+d  
} F60m]NUM)c  
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