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http断点续传简单实现(java)

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/* <& 8cq@<  
**SiteFileFetch.java A*n'"+_  
*/ - tF5$pb'  
package NetFox; RB\>$D  
import java.io.*; Cm JI"   
import java.net.*; G( nT.\  
> 9JzYI^  
_ Eq:Qbw#  
public class SiteFileFetch extends Thread { BpDf4)|  
yh]#V"W3  
X3!btxa% t  
SiteInfoBean siteInfoBean = null; //文件信息Bean Fng":28o  
long[] nStartPos; //开始位置 *Mg=IEu-6[  
long[] nEndPos; //结束位置 jzI\Q{[m'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~~;fWM '  
long nFileLength; //文件长度 X z2IAiAs'  
boolean bFirst = true; //是否第一次取文件 f>\?\!  
boolean bStop = false; //停止标志 ro}plK(<WQ  
File tmpFile; //文件下载的临时信息 >J3N,f  
DataOutputStream output; //输出到文件的输出流 ^gw_Up<e6  
>LgV[D#=&o  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) s)375jCga  
public SiteFileFetch(SiteInfoBean bean) throws IOException hs2f3;)  
{ (vz)GrH>  
siteInfoBean = bean; :?@d\c '  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y:iE'SRRK6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); VpWax]'  
if(tmpFile.exists ()) A8e b{qv  
{ [9z<*@$-  
bFirst = false; bNevHKS  
read_nPos(); ^+mSf`5  
} yHCQY4/  
else G+m|A*[>  
{ UB.FX  
nStartPos = new long[bean.getNSplitter()]; h[C!cX  
nEndPos = new long[bean.getNSplitter()]; yf3%g\k  
} yIXM}i:  
^(N+s?  
. 2.$Rq  
feIAgd},  
} wx}\0(]Gl  
BtBy.bR  
f|Z3VS0x  
public void run() >f'n l  
{ ^-~.L: }q  
//获得文件长度 q_OIzZ@  
//分割文件 / w_ Sc{  
//实例FileSplitterFetch R@=ve %a-  
//启动FileSplitterFetch线程 Rk"VFe>r  
//等待子线程返回 viD+~j18  
try{ #ZCgpg$wM  
if(bFirst) 67 7p9{:  
{ K\IS"b3X  
nFileLength = getFileSize(); ,{%/$7)  
if(nFileLength == -1) H#m)`=nZSZ  
{ x2Y1B  
System.err.println("File Length is not known!"); H<}<f:  
} 0>H<6Ja  
else if(nFileLength == -2) ItYG9a  
{ /A_</GYs  
System.err.println("File is not access!"); A. U<  
} @`wBe#+\  
else q jDW A'  
{ P6i4Dr  
for(int i=0;i<nStartPos.length;i++) KbMgatI/  
{ X[j4V<4O  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gBYL.^H^l  
} Hi,_qlc+  
for(int i=0;i<nEndPos.length-1;i++) m ~fqZK  
{ y<BiR@%,7  
nEndPos = nStartPos[i+1]; A{x &5yX8  
} q,aWF5m@  
nEndPos[nEndPos.length-1] = nFileLength; +**H7: bO  
} iBN,YPo~  
} 9^v|~f  
?Sn$AS I  
;L(W'+  
//启动子线程 ?7^('  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7fI[yCh  
for(int i=0;i<nStartPos.length;i++) kzJNdYtdH  
{ 6}C4 SZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U+@yx>!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^=OjsN  
nStartPos,nEndPos,i); eJ'2 CM6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jc`LUJT  
fileSplitterFetch.start(); Ip.5I!h[Xb  
} 7Ar4:iNvX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *: e^yi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %j2YCV7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eK/[jxNO  
nEndPos = " + nFileLength); U QXT&w  
// fileSplitterFetch[nPos.length-1].start(); .X_k[l9  
7<IrN\@U  
bxkp9o  
//等待子线程结束 1'c!9  
//int count = 0; {(D$ Xb  
//是否结束while循环 [Gh T.  
boolean breakWhile = false; Y&Pi`E9=  
Yx(?KN7V?  
OjJlGElw  
while(!bStop) (mt,:hX  
{ E|6X.Ny]   
write_nPos(); fU>"d>6!S  
Utility.sleep(500); i&mu=J[  
breakWhile = true; Z=8 25[p  
VG2TiR1  
;]Y.2 J  
for(int i=0;i<nStartPos.length;i++) ZS>}NN  
{ m[ay  
if(!fileSplitterFetch.bDownOver) /Wg$.<!5 }  
{ g@MTKqs  
breakWhile = false; G A2S  
break; ouVR[w>V  
} kn+`2-0  
} jBI VZ!X  
if(breakWhile) w^G<]S {l  
break; |;OM,U2  
ZN%$k-2  
?Q9/C|  
//count++; ,GVHwTZ0`  
//if(count>4) kSB)}q6a  
// siteStop(); RBt"7'  
} /}#z/m@bN  
S@N&W&W#~  
l:j9lBS  
System.err.println("文件下载结束!"); D'Byl,W$   
} Uk|Xs~@#E  
catch(Exception e){e.printStackTrace ();} B`"-~4YAf  
} OR1XQij  
+P}'2tE~'  
:!g|0CF_  
//获得文件长度 ^4B6IF*  
public long getFileSize() yK"U:X  
{ i @+Cr7K,  
int nFileLength = -1; 7" Dw4}T  
try{ e3) rF5pp  
URL url = new URL(siteInfoBean.getSSiteURL()); C*kZ>mbc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,dzbI{@6  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2#T|+mKxZM  
r'{pTgm#  
f+fF5Z\  
int responseCode=httpConnection.getResponseCode(); Pa0tf:  
if(responseCode>=400) jY87N Hg  
{ s67$tlV  
processErrorCode(responseCode); 0/{-X[z  
return -2; //-2 represent access is error aJI>qk h?]  
} S U2`H7C*  
1tQZyHc42;  
#3kR}Amow  
String sHeader; 53BXz= k  
WAqR70{KM  
#mx;t3ja7  
for(int i=1;;i++) RL.%o?<&?  
{ +Nc|cj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sGMC$%e}  
//Utility.log(in.readLine()); [gIStKe  
sHeader=httpConnection.getHeaderFieldKey(i); |I)xK@7  
if(sHeader!=null) iu*u|e  
{ pOIFO =k  
if(sHeader.equals("Content-Length")) +;FF0_   
{ `!!A;G7Qg  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h^x7[qe  
break; d/P$qMD  
} UO<uG#FB  
} 0<!kGL5  
else s:I^AL5  
break; -uy}]s5Qu  
} yq6!8OkF  
} !QcgTW)T  
catch(IOException e){e.printStackTrace ();} lS XhHy  
catch(Exception e){e.printStackTrace ();} >=C)\Yfu)  
XRP/E_4  
a ^4(7  
Utility.log(nFileLength); d@,q6R}!MP  
JXUO?9  
9dqD(S#C;"  
return nFileLength; 2=F_<Jh|+  
} -}4H'%Z(i  
Yk?ux Z4)H  
+-qD!(&-6  
//保存下载信息(文件指针位置) '~3( s?B  
private void write_nPos() cX *  
{  78qf  
try{ LP=!u~?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0IQu6 X  
output.writeInt(nStartPos.length); 5jx{O${u  
for(int i=0;i<nStartPos.length;i++) OK3B6T5w=  
{ eA{,=, v)  
// output.writeLong(nPos); ;E* ^AW  
output.writeLong(fileSplitterFetch.nStartPos); 9L!Vj J  
output.writeLong(fileSplitterFetch.nEndPos); 4.H!rkMM  
} ``aoLQc`  
output.close(); >%Y.X38Z[  
} >s[}f6*2@  
catch(IOException e){e.printStackTrace ();} Oo rH  
catch(Exception e){e.printStackTrace ();} Wd~}O<"  
} 7@+0E 2'  
s_D7?o  
K8284A8v  
//读取保存的下载信息(文件指针位置) 'Nfg%)-N  
private void read_nPos() 1D=My1B  
{ I0Wn?Qq=@  
try{ Haq23K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zx=A3I%7 A  
int nCount = input.readInt(); 1REq.%/=  
nStartPos = new long[nCount]; >6jy d{  
nEndPos = new long[nCount]; R`TM@aaS:  
for(int i=0;i<nStartPos.length;i++) [>C^ 0\Z~  
{ ag|d_;  
nStartPos = input.readLong(); mI0| lp 1$  
nEndPos = input.readLong(); ks(PH6:]<  
}  pSV 8!  
input.close(); G=yQYsC$  
} Jv7 @[<$  
catch(IOException e){e.printStackTrace ();} r~t&;yRv  
catch(Exception e){e.printStackTrace ();} P 3lN ns3  
} 4fP>;9[F  
r10)1`[  
2<u vz<B  
private void processErrorCode(int nErrorCode) Z(xn-  
{ V :d/;~  
System.err.println("Error Code : " + nErrorCode); rp(`V@x3  
} &,NHk9.aq  
YdC:P# Nf  
]S;e#u{QE  
//停止文件下载 f)"O( c  
public void siteStop() e[Q(OV5(R  
{ 8&dmH&  
bStop = true;  0A pvuf1  
for(int i=0;i<nStartPos.length;i++) M{O2O(  
fileSplitterFetch.splitterStop(); 5 0~L(<  
{(xNC#   
'|WMt g  
} #-e3m/>  
} 8&`s wu&  
//负责部分文件的抓取 j}0*`[c  
**FileSplitterFetch.java <`6-J `.  
*/ joM98H@  
package NetFox; j q1qj9KZ  
K")-P9I6-f  
W]6Y buP:  
import java.io.*; Yng9_w9Y  
import java.net.*; b3Y9  
L$7v;R3  
sjShm  
public class FileSplitterFetch extends Thread { CgEeO,N]j  
7p u*/W~  
tk1qgjE(?  
String sURL; //File URL +twBFhS7k  
long nStartPos; //File Snippet Start Position BT`/O D@  
long nEndPos; //File Snippet End Position < >f12pu  
int nThreadID; //Thread's ID {yspNyOx  
boolean bDownOver = false; //Downing is over /\#qz.c2K  
boolean bStop = false; //Stop identical N;Hf7K  
FileAccessI fileAccessI = null; //File Access interface %v}:#_va]  
.HGEddcC  
8V~w3ssz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException XPWK"t0 1  
{ mYa0_P%^  
this.sURL = sURL; ~^Vt)/}Q  
this.nStartPos = nStart; HnOp*FP  
this.nEndPos = nEnd; kw=+"U   
nThreadID = id; A:NsDEt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 WdIr 3  
} hnE@+(d=qJ  
 $7|0{Dw  
o`G'E&  
public void run() {#Gr=iv~N  
{ <V>vDno\  
while(nStartPos < nEndPos && !bStop) tYmWze. j  
{ S~Nx;sB  
<niHJ*  
'%K,A-7W  
try{ %li'j|  
URL url = new URL(sURL); <([o4%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u!{P{C  
httpConnection.setRequestProperty("User-Agent","NetFox"); q;B-np?U  
String sProperty = "bytes="+nStartPos+"-"; '1.T-.4>&  
httpConnection.setRequestProperty("RANGE",sProperty); ?CmW{9O  
Utility.log(sProperty); NSM-p.I9  
!>t |vgW  
rJ!xzge;G  
InputStream input = httpConnection.getInputStream(); c*1B*_08  
//logResponseHead(httpConnection); 3(FJ<,"D}  
'lIT7MK  
:/Sx\Nz78  
byte[] b = new byte[1024]; M[TgNWl/[  
int nRead; eJJvEvZ,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }tj@*n_  
{ UyK|KL  
nStartPos += fileAccessI.write(b,0,nRead); $ n 7dIE  
//if(nThreadID == 1) B8B^@   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^>k[T.  
} gX6'!}G8]  
m_(+-G  
_W?}%;  
Utility.log("Thread " + nThreadID + " is over!"); oN)K2&M0  
bDownOver = true; :X2B+}6_&  
//nPos = fileAccessI.write (b,0,nRead); c&F"tLl  
} t ;y>q  
catch(Exception e){e.printStackTrace ();} . 6Bz48*  
} S ._9  
} c9f~^}jNb  
G}f.fR Y  
H!oP!rzEo  
//打印回应的头信息 y4M<L. RO  
public void logResponseHead(HttpURLConnection con) H> _%ZXL  
{ YSv\T '3  
for(int i=1;;i++) bU_9GGG|  
{ HjV83S;  
String header=con.getHeaderFieldKey(i); :K2N7?shA  
if(header!=null) W13$-hf9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UY)YhXW  
Utility.log(header+" : "+con.getHeaderField(header)); JH<q7Y6!y  
else Ybd){Je"z  
break; *"1]NAz+  
} c%i/ '<Afr  
} 2r[Q$GPM<  
D97oS!*  
SDdK5@1O4o  
public void splitterStop() bl}$x/  
{ ~?[@KK  
bStop = true; 9e8@0?0  
} oa;[[2c  
=_L"x~0I-  
1Qf5H!5vx  
} Mgf80r=  
t{84ioJ"$  
hDVD@b  
/* <\Y>y+$3  
**FileAccess.java b6);bX>e  
*//文件访问(定位,写) pm<<!`w"  
package NetFox; }$m_):t@@  
import java.io.*; PO |p53  
{WFYNEQ[  
R2u[IVZW:-  
public class FileAccessI implements Serializable{ E})PNf;  
C{Aeud #5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y>Nlj%XH  
RandomAccessFile oSavedFile; . KRh59yg  
long nPos; D~2,0K  
?]$.3azO  
m,)Re8W-  
public FileAccessI() throws IOException (Dc dR:/=  
{ N}.h_~6  
this("",0); p3sz32RX  
} hQHV]xW  
h2uO+qEsu  
x?Q;o+2v  
public FileAccessI(String sName,long nPos) throws IOException jY$|_o.4  
{ -41L^Di\  
oSavedFile = new RandomAccessFile(sName,"rw"); .}a@OLJd  
this.nPos = nPos; YZ/mTQn_D  
oSavedFile.seek(nPos); KX`MX5?x  
} 5/neV&VcB  
}Y<(1w  
5_=&U-? H  
public synchronized int write(byte[] b,int nStart,int nLen) -FE5sW  
{ KDHR} `  
int n = -1; xa!@$w=U&  
try{ e2/[`k=7-  
oSavedFile.write(b,nStart,nLen); pMs%`j#T  
n = nLen; ]RGun GJ  
} %;ny  
catch(IOException e) :vV?Yv%P)n  
{ bpKb<c  
e.printStackTrace (); !f_Kq$.{  
} Q.vtU%T  
z2nDD6N  
F>!fu.Ws  
return n; g($y4~#  
} N2q'$o  
~-'nEATE  
aD%")eP%&  
} X0P<ifIv  
C]eb=rw$  
P#76ehR]K  
/* Pf(z0o&  
**SiteInfoBean.java 5 _] i==M  
*/ ydoCoD w  
package NetFox; u~a<Psp&|  
'nW:2(J  
R},mq&f5  
public class SiteInfoBean { 2b3x|9o8  
Y}e$5  
Xj|j\2$ 0  
private String sSiteURL; //Site's URL ;QW)tv.y  
private String sFilePath; //Saved File's Path &({X9  
private String sFileName; //Saved File's Name 9> [ $;>  
private int nSplitter; //Count of Splited Downloading File 6VCw>x  
vgsu~(L;  
IvH0sS`F  
public SiteInfoBean() MPNBA1s  
{//nSplitter的缺省值为5 bha_bj  
//default value of nSplitter is 5 iOzw)<  
this("","","",5); % sT=>\  
} ^Z2%b>  
cl14FrpYu  
?XW+&!ar  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2nOQ48ha T  
{ RwY) O5  
sSiteURL= sURL; &eg]8kV  
sFilePath = sPath; # Wh"_zpM+  
sFileName = sName; gp(w6 :w  
this.nSplitter = nSpiltter; S(/@.gI:f  
*|hICTWL  
\XmtSfFC  
} MqXA8D  
 rd. "mG.  
Q:@Y/4=  
public String getSSiteURL() va#~ \%`  
{ %qN8u Qx  
return sSiteURL;  EMJio\  
} GawLQst[+  
ZLo3 0*  
sveFxI  
public void setSSiteURL(String value) tA'i-D&  
{ <>2QDI6_  
sSiteURL = value; )3z.{.F  
} 31J7# S2  
Fda<cS]  
)lH?XpfTjm  
public String getSFilePath() 5.5dB2w  
{ ilpg()  
return sFilePath; zg|yW6l)9  
} 9;JU c0%  
qlDLZ.  
pOw4H67  
public void setSFilePath(String value) }]tSWVb*  
{ {s_0[>  
sFilePath = value; b!_l(2  
} dp_J*8  
WET $H,  
5%,n[qj4IT  
public String getSFileName() .DCp)&m l;  
{ l,sYYU+iY  
return sFileName; $F\&?B1.  
} %Sxy!gGz%%  
\h _hd%'G  
${e(#bvGZ  
public void setSFileName(String value) $?I ^Dk  
{ 9$S2:2(G  
sFileName = value; 0*q~(.>a  
} @AVx4,!>[  
,CwhpW\Y  
;2%3~L8?V  
public int getNSplitter() [y>Q3UqN  
{ /rJvw   
return nSplitter; 9.PY49|  
} ;41s&~eR  
$3"0w   
 Zp]Bs  
public void setNSplitter(int nCount) t_P1a0Zu  
{ 28Q`O$=v  
nSplitter = nCount; 4#4kfGoT  
} uA\A4  
} v }P~g  
;#f_e;  
j:U>V7Kn3~  
/* z,/dYvT<  
**Utility.java 6o6!O l  
*/ zM[WbB+"m  
package NetFox; [o|]>(tk  
^k u~m5v  
hFQC%N. '  
public class Utility { Zad+)~@!tq  
-cIc&5CS  
yf_<o   
public Utility() '_(oa<g  
{ QZQ@C#PR;  
g/V C$I!'  
BAqu@F\):  
} q_HD`tW  
9n9/[?S  
//线程睡眠 QF-.")Z  
public static void sleep(int nSecond) 1mA)=hu  
{ ?;uzx7@F  
try{ .[K{;^>  
Thread.sleep(nSecond); 9HP)@66  
} Oi l>bv8  
catch(Exception e) 1Kwl_jf  
{ ilFM+x@  
e.printStackTrace (); RAf+%h*  
} @A$%baH0  
} @/|sOF;8W  
NP%ll e,l  
//日志 y"7TO#  
public static void log(String sMsg) G++kU o<  
{ B}r@xz  
System.err.println(sMsg); D.$EvUSK<.  
} Xb|hP  
X ,T^(p  
@LwhQ  
public static void log(int sMsg) sM~CP zMa  
{ +R#*eo;o7  
System.err.println(sMsg); Nnv&~ D>  
} ,0#OA* 0B  
} `.[hOQ7  
GlD@Ud>o)  
nJ2l$J<  
/* a$9UUH-|  
**TestMethod.java T_YN^za(q  
*/ UPJgTN*  
package NetFox; YXD1B`23  
Eb{TKz?  
KHF5Nt  
public class TestMethod { <<n8P5pXt  
F!aYK2  
~{+J~5!;<H  
public TestMethod() t7)Y@gRy  
{ ///xx/weblogic60b2_win.exe S :(1=@  
try{ qJISB7F[%O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^Ko0zz|R/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %}$6#5"';  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |fRajuA;  
fileFetch.start(); )xTp7YnZ;  
} bh+R9~  
catch(Exception e){e.printStackTrace ();} ed\,FWR  
'7_'s1  
_^&oNm1  
} NK"y@)%0  
D8Ni=.ALL  
I`5MAvP  
public static void main(String[] args) 5Vut4px  
{ "q]v2t  
new TestMethod(); u45e>F=  
} TR ]lP<m  
} YK"({Z>U  
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