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http断点续传简单实现(java)

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/* sRYFu%  
**SiteFileFetch.java 4!E6|N%f  
*/ *[ A%tj%  
package NetFox; [!DLT6Qk  
import java.io.*; ea B-u  
import java.net.*; ?(R6}ab>K7  
) tsaDG-E  
yfaXScbE  
public class SiteFileFetch extends Thread { UUA7m$F1  
m >'o&Hj  
AQ-PY  
SiteInfoBean siteInfoBean = null; //文件信息Bean o"5R^a@  
long[] nStartPos; //开始位置 FC)aR[  
long[] nEndPos; //结束位置 &&t4G}*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Dj %jrtT  
long nFileLength; //文件长度 ybB/sShGM  
boolean bFirst = true; //是否第一次取文件 8"p>_K=  
boolean bStop = false; //停止标志 r$0" Y-a  
File tmpFile; //文件下载的临时信息 %,)[%>#{  
DataOutputStream output; //输出到文件的输出流 T>L6 X:d  
`U?;9!|;6  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `cf&4Hn  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ip<STz]-  
{ h05 ~ g  
siteInfoBean = bean; [kn`~hI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LM<OYRB(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l tQ:c  
if(tmpFile.exists ()) %n{E/06f  
{ Z*kg= hs^  
bFirst = false; .YLg^JfZ  
read_nPos(); g*!2.P  
} ,V |>nkQ  
else pU}>}  
{ -3bl !9h^  
nStartPos = new long[bean.getNSplitter()]; 7@C :4c@0  
nEndPos = new long[bean.getNSplitter()]; =f{r+'[;^  
} ~KrzJp=5F  
J *^|ojX  
]D<r5P%  
18|H  
} oIf -s[uH  
r@iGM Jx$  
6Zkus20  
public void run() I`FH^=  
{ unP7("A0D  
//获得文件长度 P 7gS M  
//分割文件 JYKaF6bx8  
//实例FileSplitterFetch h-#Glse<  
//启动FileSplitterFetch线程 q/&Z6LJ)  
//等待子线程返回 ]D(%Ku,O%  
try{ DBVe69/S  
if(bFirst) |-2,k#|  
{ l |\Q~ D!o  
nFileLength = getFileSize(); ^<ayPV)+  
if(nFileLength == -1) kOJs;k  
{ *mq+w&  
System.err.println("File Length is not known!"); !U*i13  
} I~#'76L[  
else if(nFileLength == -2) ~6{;3"^<  
{ : h-N  
System.err.println("File is not access!"); aS62S9nwX  
} nq A> }A  
else ~ ]o .Mv a  
{ +vJ[k2d  
for(int i=0;i<nStartPos.length;i++) whxE[Xnv  
{ v{&cgod  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u:"mq.Q  
} 8 =J6{{E  
for(int i=0;i<nEndPos.length-1;i++) |W{z,e01x  
{ $t[`}I }  
nEndPos = nStartPos[i+1]; z\Qg 3BS  
} He&dVP  
nEndPos[nEndPos.length-1] = nFileLength; ]< TgBo|  
} epz2d~;  
} mltN$b%G=d  
=yvyd0|35  
2h u;N  
//启动子线程 6g( 2O[n.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; WG(tt.  
for(int i=0;i<nStartPos.length;i++) U%j=)VD ])  
{ O"_FfwO a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *H:;pI WP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4l>/6LNMF  
nStartPos,nEndPos,i); PNc^)|4^Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IjJ3./L!5  
fileSplitterFetch.start(); QT^W00h  
} xZbm,. v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \q%li)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H@5:x8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -F@Rpfrj_#  
nEndPos = " + nFileLength); /]iv9e{uh(  
// fileSplitterFetch[nPos.length-1].start(); Rq9v+Xq2  
UiF?Nx~  
1JJQ(b  
//等待子线程结束 RLecKw&1{3  
//int count = 0; LlX 7g _!  
//是否结束while循环 vM|?;QM  
boolean breakWhile = false; n%W~+  
EKq9m=Ua@o  
VO[s:e9L  
while(!bStop) 3*XX@>|o  
{ @dD70T  
write_nPos(); (fb&5=Wzw  
Utility.sleep(500); o#H"tYP  
breakWhile = true; )O2giVq7[0  
CzST~*lH  
~vBmW_j  
for(int i=0;i<nStartPos.length;i++) 3[aCy4O  
{ fg+Q7'*Vq  
if(!fileSplitterFetch.bDownOver) gx@b|rj;  
{ jA<v<oV  
breakWhile = false; ZrXvR`bsw  
break; .6f %"E,  
} [6)`wi  
} 4LJUO5(y@  
if(breakWhile) r9z/hm}E  
break; jZ7#xRt5w  
@kRe0:t  
jQC6N#L  
//count++; FC/m,D50oI  
//if(count>4) rh?!f(_@  
// siteStop(); w\8grEj  
} Cf J@|Rh  
kbBX\*{yh  
7bCTR2e\@w  
System.err.println("文件下载结束!"); $kvF]|<bu  
} Vb|DNl@  
catch(Exception e){e.printStackTrace ();} q2Ax-#  
} a~DR$^m  
j+w*Absh  
uXNJ{]o  
//获得文件长度  lrU}_`  
public long getFileSize() tWdj"n%  
{ UYD(++  
int nFileLength = -1; Z?O aY4  
try{ h 5t,5e}  
URL url = new URL(siteInfoBean.getSSiteURL()); `lqMifD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )pW(Cp  
httpConnection.setRequestProperty("User-Agent","NetFox"); 03iO4yOu  
8'@pX<  
W2qW`Ujo{  
int responseCode=httpConnection.getResponseCode(); =>n:\_*M  
if(responseCode>=400) xaAJ>0IM  
{ ?)'j;1_=E3  
processErrorCode(responseCode); #ZeZs31  
return -2; //-2 represent access is error Uw)?u$+ P  
} o5 @ l!NQ  
#4Xe zj,g*  
"Z#97Jc+J  
String sHeader; w}K<,5I>  
0^?(;AK  
z2A7:[  
for(int i=1;;i++) `.>2h}op  
{ n,bZj<3t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (Lo<3a-]  
//Utility.log(in.readLine()); Jou~>0,/j  
sHeader=httpConnection.getHeaderFieldKey(i); =YE"6iU  
if(sHeader!=null) 1 nIb/nY  
{ :L&-  
if(sHeader.equals("Content-Length")) LoPWho[8  
{ S%R:GZEf_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :S{[^ -"  
break; %j^[%&pT  
} =Bu d!  
} .3Jggp  
else #x" 4tI  
break; r> eOq[z  
} 0jro0f'  
} {ckA  
catch(IOException e){e.printStackTrace ();} mrS:|| ,_  
catch(Exception e){e.printStackTrace ();} gmJiKuAL5  
Xv|~1v%s7  
k?o(j/  
Utility.log(nFileLength); I)U|~N  
^ RU"v>  
C(Yk-7  
return nFileLength; APsd^J  
} A=Q"IdK  
/9/=]  
h?p&9[e`  
//保存下载信息(文件指针位置) @D[jUC$E  
private void write_nPos() X25cU{  
{ Q Bc\=}  
try{ lGwX.cA!'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LBk1Qw}-  
output.writeInt(nStartPos.length); hvnZ 2x.?d  
for(int i=0;i<nStartPos.length;i++) RM|<(kq  
{ .\7R/cP}{A  
// output.writeLong(nPos); ~raRIh=  
output.writeLong(fileSplitterFetch.nStartPos);   lCr  
output.writeLong(fileSplitterFetch.nEndPos); ;HlVU  
} =q.2S; ?  
output.close(); B- N  
} AA:Ch?  
catch(IOException e){e.printStackTrace ();} 6! \a8q'z  
catch(Exception e){e.printStackTrace ();} _S7GkpoK  
} <*<7p{x  
ff**)Xdh  
l}&egq DC  
//读取保存的下载信息(文件指针位置) n9B1NM5 \  
private void read_nPos() jFZJ #'CNS  
{ 3l0x~  
try{ 3+;]dqZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v<,? %(g)7  
int nCount = input.readInt(); qY]IX9'kV  
nStartPos = new long[nCount]; cxFfAk\,en  
nEndPos = new long[nCount]; {a-p/\U  
for(int i=0;i<nStartPos.length;i++) S^HuQe!#  
{ I $!Y  
nStartPos = input.readLong(); 4E}]>  
nEndPos = input.readLong(); w^sM,c5d  
} r]iec{ ^  
input.close(); _'JKPD[  
} Xhe25  
catch(IOException e){e.printStackTrace ();} MR=>DcR  
catch(Exception e){e.printStackTrace ();} zHw[`"[  
} 0.4c|-n  
2~AGOx  
6Daz1Pxd+  
private void processErrorCode(int nErrorCode) ^n"ve2   
{ ~T7\lJ{%G  
System.err.println("Error Code : " + nErrorCode); &EYO[~D06  
} ?*zRM?*  
J 6U3}SO=y  
rLGh>bw#`3  
//停止文件下载 ev7Y^   
public void siteStop() |_{-hNiz0  
{ y,v*jE  
bStop = true; Lj6$?(x}  
for(int i=0;i<nStartPos.length;i++) <?5 ,3`V  
fileSplitterFetch.splitterStop(); bm*Ell\a.  
sNZ{OD+  
JeU|e$I4>  
} WUkx v*  
} 5K|1Y#X  
//负责部分文件的抓取 V)V\M6  
**FileSplitterFetch.java c~[L ;_  
*/ ZP61T*n  
package NetFox; w&:"x@ -|  
Gt{~u^<  
8q{ %n   
import java.io.*; tbrjTeC  
import java.net.*; Fr?o 4E6h  
N>giFj[dD  
^P >; %  
public class FileSplitterFetch extends Thread { fn>MOD!l  
Z.Z+cFi  
TXD\i Dq  
String sURL; //File URL n,SDJsS^  
long nStartPos; //File Snippet Start Position JL45!+  
long nEndPos; //File Snippet End Position (dvCejc^p  
int nThreadID; //Thread's ID vG`R.  
boolean bDownOver = false; //Downing is over _ #288`bU  
boolean bStop = false; //Stop identical h lD0^8S  
FileAccessI fileAccessI = null; //File Access interface 7Rqjf6kX`O  
v@TP_Ka  
y[BUWas(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jk,: IG  
{ ZgVYC4=Q-\  
this.sURL = sURL; p@!{Sh  
this.nStartPos = nStart; z)I.^  
this.nEndPos = nEnd; T|`nw_0  
nThreadID = id; AI}29L3C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !%>p;H%0  
} PB*m D7"  
3Z;`n,g  
9ar+Ph@*  
public void run() TC;2K,.#k  
{ 4Z5ZV!  
while(nStartPos < nEndPos && !bStop) DS0c0lsx  
{ JJ[.K*dO  
Z;`ts/?SY]  
oY{L0B[  
try{ 42kr&UY&  
URL url = new URL(sURL); |{udd~oE&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Elw fqfO  
httpConnection.setRequestProperty("User-Agent","NetFox"); fw Ooi 'jb  
String sProperty = "bytes="+nStartPos+"-"; p3>p1tC  
httpConnection.setRequestProperty("RANGE",sProperty); *J,VvO 9  
Utility.log(sProperty); T+7-6y+ d  
6Ty;m>j  
?G%C}8a  
InputStream input = httpConnection.getInputStream(); MlVN'w  
//logResponseHead(httpConnection); bII pJQ1.[  
-}Vnr\f  
i_8v >F  
byte[] b = new byte[1024]; Q{1Q w'+@  
int nRead; ?_*X\En*3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \7o&'zEw  
{ 9}LcJ  
nStartPos += fileAccessI.write(b,0,nRead); P0,@#M&  
//if(nThreadID == 1) Lq<#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |tF:]jnIt  
} BU],,t\  
?o307 r  
y5gTd_-  
Utility.log("Thread " + nThreadID + " is over!"); Dz4e.tvN  
bDownOver = true; tGv5pe*r  
//nPos = fileAccessI.write (b,0,nRead); .BP@1K  
} t[/WGF&(R  
catch(Exception e){e.printStackTrace ();} =?hGa;/rb  
} },<(VhP  
} %X)w$}WH  
MHNuA,cz  
91'i7&~xdG  
//打印回应的头信息 KG7 ~)g  
public void logResponseHead(HttpURLConnection con) +ve S~   
{ oZm)@Vv;  
for(int i=1;;i++) ~.\CG'g  
{ &p|+K XIf  
String header=con.getHeaderFieldKey(i); tP/0_^m  
if(header!=null) b?S,%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x UM,"+h  
Utility.log(header+" : "+con.getHeaderField(header)); OI:G~Wg  
else ?Vg251-H  
break; jNRR=0  
} &5k$ v^W5  
} HoE@t-S  
5eS0 B{,c  
U4`6S43ki  
public void splitterStop() ;nS.t_UW.  
{ gp@X(d  
bStop = true; tgk] sQY  
} YQ/  
R.nAD{>h*  
!V/Vy/'` *  
} C]/]ot0%t  
vl1`s ^}R  
$=&a 0O#  
/* v0psth?qV  
**FileAccess.java $aIq>vJO9  
*//文件访问(定位,写) c:? tn  
package NetFox; 02+ k,xFb  
import java.io.*; [{R^!Az&b<  
*nZe|)m  
?w/i;pp<,  
public class FileAccessI implements Serializable{ 3(?V!y{@  
S)`%clN}J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B8J_^kd  
RandomAccessFile oSavedFile; 7T7 A\  
long nPos; l=+hs  
,v<GSiO  
7nsn8WN[  
public FileAccessI() throws IOException 8rZJvE#c  
{ y^OT0mZkg  
this("",0); QlxzWd3=q  
} | R\PQ/)  
P_7QZ0k/  
OO$YwOKS  
public FileAccessI(String sName,long nPos) throws IOException 8s+9PE  
{ lk/T| 0])  
oSavedFile = new RandomAccessFile(sName,"rw"); 'c]Fhe fb  
this.nPos = nPos; Ddu1>"p-x  
oSavedFile.seek(nPos); F"|OcKAA}h  
} 0[\sz>@  
>]/RlW[  
0Wd2Z-I  
public synchronized int write(byte[] b,int nStart,int nLen) C_5o&O8Bc  
{ Ufw_GYxan  
int n = -1;  Z|t`}lK  
try{ ([g[\c,H  
oSavedFile.write(b,nStart,nLen); Sm7O%V8{p  
n = nLen; Dt#( fuk#  
} *P:!lO\|  
catch(IOException e) /w|!SZB  
{ V= wWY*C  
e.printStackTrace (); HGiO}|q :  
} #3 ~#`&  
:r+BL@9  
o54/r#~fi  
return n; Yee% <<S  
} )c6t`SBwi  
@XJzM]*w&  
0pfgE=9  
} Qq7%{`< }  
fpPB_P{Ua  
tZL|;K  
/* s@$SM,tnn  
**SiteInfoBean.java s!g06F  
*/ 59R%g .2Y  
package NetFox; ;:WM^S  
uge~*S  
r*F^8_YMK  
public class SiteInfoBean { +sY8<y@%  
6d;_}  
4{v?<x8  
private String sSiteURL; //Site's URL 6?`3zdOeO  
private String sFilePath; //Saved File's Path c*!xdK  
private String sFileName; //Saved File's Name )i^+=TZq  
private int nSplitter; //Count of Splited Downloading File Jc=~BT_G  
eV5 e:9  
>LAhc7I  
public SiteInfoBean() f,(@K%  
{//nSplitter的缺省值为5 6,raRg6  
//default value of nSplitter is 5 <(E9U.  
this("","","",5); 6Cpn::WW}  
} QJH((  
xo GX&^=  
7*MjQzg-P  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NScUlR"nE  
{ A [hvT\X  
sSiteURL= sURL; eWk W,a  
sFilePath = sPath; 6Zx'$F.iqK  
sFileName = sName; :OKU@l|  
this.nSplitter = nSpiltter; 'Szk!,_  
@{ CP18~:  
UCBx?9O/0  
} $/)0iL{0  
KvvG H-]  
(?vKe5  
public String getSSiteURL() Z~{0x#?4%  
{ 4#Rq}/h  
return sSiteURL; RD_l  
} 8mn zxtk  
m=#<   
JY0}#FtgV  
public void setSSiteURL(String value) df R?O#JPU  
{ ?y|8bw<  
sSiteURL = value; ba "_ !D1  
} EmYu]"${1  
+ab#2~,)  
4|INy =<"t  
public String getSFilePath() gk^`-`P  
{ b8O }XB  
return sFilePath; 1,Uf-i  
} C'&t@@:  
w:|YOeP  
b/g~;| <  
public void setSFilePath(String value) XTKAy;'5  
{ k%K\~U8"  
sFilePath = value; O|e/(s?$  
} W*Gp0pX  
N 6t`45  
m^%Xl@V:c-  
public String getSFileName() z#Cgd-^7.#  
{ OlcWptM$  
return sFileName; (U_dPf  
} F !MxC  
"tUc  
" o>` Y  
public void setSFileName(String value) y"nL9r.,:  
{ ,0^9VWZV  
sFileName = value; 5cZKk/"Ad}  
} KKGwMJku}  
|n~Vpy  
K-6+fgeB  
public int getNSplitter() rrc>O*>{i  
{ *<l9d  
return nSplitter; #(dERET*  
} F m$;p6&j  
tKLAA+Z  
be(p13&od  
public void setNSplitter(int nCount) |>Wi5h{6X  
{ x-Fl|kwX.5  
nSplitter = nCount; QV*W#K\7q  
} qy,X#y'FuE  
} e =4k|8G  
MtXd}/  
V?C_PMa  
/* W}.p,d  
**Utility.java F94Qb}  
*/ :qxd s>Xm  
package NetFox; 3=Va0}#&  
7p+uHm  
JNSH'9!n6  
public class Utility { hZDv5]V:0  
O/{W:hJjd  
.ta*M{t  
public Utility() G{{Or  
{ pNzpT!}H>  
m9li%p  
HH aerc  
} O\[Td  
MnT+p[.  
//线程睡眠 jY8u1z  
public static void sleep(int nSecond) QAK.Qk?Qu  
{ RWK##VHK  
try{ SPY4l*kX  
Thread.sleep(nSecond); f')3~)"  
} '$5o5\  
catch(Exception e) GcA!I!j/  
{ a&~]77)  
e.printStackTrace (); )`gE-udR  
} #^;^_  
} 8- ]7>2?_  
WA79(B  
//日志 G)wIxm$?0  
public static void log(String sMsg) "K$ y(}C  
{ gKay3}w  
System.err.println(sMsg); `@r#o&  
} y1zep\-D  
h | +(  
K#],4OG  
public static void log(int sMsg) *3We5  
{ wfc[B;K\  
System.err.println(sMsg); n\D3EP<s  
} D:Y `{{  
} l5d> YTK+5  
OJ\rT.{  
TAn.5 wH9t  
/* w=H4#a?fc  
**TestMethod.java SsF 5+=A  
*/ M[ZuXH}  
package NetFox; mca9 +v  
jw!QjVuRN%  
BA+:}81&<q  
public class TestMethod { /,Sd  
!saKAb}d7H  
k&>l#oH  
public TestMethod() JI}p{ yI  
{ ///xx/weblogic60b2_win.exe S.Fip _  
try{ ]0wmvTR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3tTz$$-#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |uE _aFQs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X@7K#@5  
fileFetch.start(); 07dUBoq  
} ,.+"10=N.  
catch(Exception e){e.printStackTrace ();} D3emO'`gQ  
vDAv/l9  
pY9>z;qD  
} tF d^5A*  
_\Cd.  
y|+ltAK  
public static void main(String[] args) T\ h_8  
{ v1j]&3O  
new TestMethod(); xR, ;^R|C  
} R.)U<`||  
} !jDqRXi(  
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