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http断点续传简单实现(java)

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/* Y-\hV6v6  
**SiteFileFetch.java 0 3fCn"  
*/ r(xh5{^x  
package NetFox; ,gGIkl&  
import java.io.*; t-Rfy`I3  
import java.net.*; D7|[:``  
 (n+2z"/  
nmZz`P9g  
public class SiteFileFetch extends Thread { << `*o[^L  
:;W[@DeO[  
> nV~5f+  
SiteInfoBean siteInfoBean = null; //文件信息Bean A^:[+PJHN  
long[] nStartPos; //开始位置 >Jh*S`e  
long[] nEndPos; //结束位置 F8M&.TE_3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y\K r@;q0w  
long nFileLength; //文件长度 CsHHJgx  
boolean bFirst = true; //是否第一次取文件 r_nB-\  
boolean bStop = false; //停止标志 Qb<i,`SN  
File tmpFile; //文件下载的临时信息 v+uq  
DataOutputStream output; //输出到文件的输出流 HE58A.Q&  
D ]Q,~Y&'  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) a0I+|fR  
public SiteFileFetch(SiteInfoBean bean) throws IOException zWKnkIit,  
{ 1BT]_ cP  
siteInfoBean = bean; c*2 U'A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n% zW6}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rx2?y3pv  
if(tmpFile.exists ()) [ZC]O2'  
{ ir/m. ~?  
bFirst = false; nMXk1`|/)x  
read_nPos(); A>WMPe:sSS  
} _DsA<SJ]  
else YoyJnl.?u  
{ m;-FP 2~  
nStartPos = new long[bean.getNSplitter()]; %B?@le+%  
nEndPos = new long[bean.getNSplitter()]; >B>[_8=f@  
} I?` }h}7.  
j8n_:;i*  
t80s(e  
_5TSI'@.4  
} V/|).YG2  
K"u-nroHW  
HT&CbEa4'  
public void run() & $E[l'  
{ `roos<F1D  
//获得文件长度  8:=&=9%  
//分割文件 o V"d%ks  
//实例FileSplitterFetch +UbSqp1BS  
//启动FileSplitterFetch线程 e ewhT ^  
//等待子线程返回 {gh41G;n  
try{ AsFn%8_I  
if(bFirst) _CqVH5U?  
{ _8t5rF  
nFileLength = getFileSize(); @>`+eg][?P  
if(nFileLength == -1) <vMna< /d  
{ K$v SdpC  
System.err.println("File Length is not known!"); *D`]7I~}  
} $pW6a %7  
else if(nFileLength == -2) iV9wqUkMv  
{ 'a.n  
System.err.println("File is not access!"); J{>9ctN  
} )9/.K'o,dy  
else A!Em J  
{ hOYm =r  
for(int i=0;i<nStartPos.length;i++) 9R_2>BDn  
{ k1tJ$}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X&C&DTB  
} j("$qp v  
for(int i=0;i<nEndPos.length-1;i++) vJZ0G:1  
{ 8vQGpIa,  
nEndPos = nStartPos[i+1]; \H<gKZquR  
} @1+C*  
nEndPos[nEndPos.length-1] = nFileLength; 8VG6~>ux'>  
} ^n8ioL\*i  
} +m?;,JGt  
& \<!{Y<'  
o95)-Wb  
//启动子线程 =5:L#` .  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G!]%xFwYa  
for(int i=0;i<nStartPos.length;i++) PJd7t% m;  
{ Pdgn9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Oi#4|*b{W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]vj.s/F~  
nStartPos,nEndPos,i); L1J \ C  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wQ1_Q8:Z  
fileSplitterFetch.start(); 'Br:f_}  
} y98 v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s|er+-'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qHwHP 1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'ec G:B`S  
nEndPos = " + nFileLength); (!b_o A8V  
// fileSplitterFetch[nPos.length-1].start(); UI:YzR  
w+A:]SU  
Skb,cKU  
//等待子线程结束 5L ]TV\\  
//int count = 0; 8CXZ7 p  
//是否结束while循环 B$A`thQp  
boolean breakWhile = false; R-7.q  
` =ocr8c  
(PVK|Q55y  
while(!bStop) dA,irb I0W  
{ 'Cki"4%<  
write_nPos(); 8H2zM IB  
Utility.sleep(500); N$'/J-^  
breakWhile = true; !Cqm=q{K  
z+@ CzHCN  
"n<rP 3y  
for(int i=0;i<nStartPos.length;i++) GCrIa Z  
{ D.7,xgH  
if(!fileSplitterFetch.bDownOver) +SM&_b  
{ rw CFt6;v  
breakWhile = false; rbC4/9G\  
break; !T+jb\O_  
} c L+-- $L  
} 0QzUcr)3+  
if(breakWhile)  ywQ>T+  
break; iJ8 5okv'  
tKr.{#)  
.`I;qF  
//count++; \o|5 /N  
//if(count>4) _:R Q9x'  
// siteStop(); eX{:&Do  
} \zdY$3z  
fGwRv% $^  
{?!0<0  
System.err.println("文件下载结束!"); y ~PW_,  
} =6sA49~M  
catch(Exception e){e.printStackTrace ();} :jKiHeBQu?  
} Y=NXfTc  
vp[;rDsIJ$  
We8n20wf<  
//获得文件长度 p{V_}:|=Q  
public long getFileSize() eU*0;#  
{ <FkoWN  
int nFileLength = -1; ?Z1&ju,Hd-  
try{ <n+]\a97*  
URL url = new URL(siteInfoBean.getSSiteURL()); XEUy,>mR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ORc20NFy7  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1"hd5a  
0\y{/P?I$  
.uoQ@3  
int responseCode=httpConnection.getResponseCode(); kPuI'EPK  
if(responseCode>=400) &'mq).I2  
{ >u-6,[(5X*  
processErrorCode(responseCode); doX8Tq   
return -2; //-2 represent access is error hoLQuh%2%  
} Uo~-^w}  
#GlQwk3  
fr19C%{  
String sHeader; q^I/  
id" -eMwp  
|_} LMkU)  
for(int i=1;;i++) (C&Lpt_  
{ NDqvt$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~{xm(p  
//Utility.log(in.readLine()); <'N(`.&3C  
sHeader=httpConnection.getHeaderFieldKey(i); H}p5qW.tH:  
if(sHeader!=null) k$NNpv&;d  
{ fqY; > Z  
if(sHeader.equals("Content-Length")) )5j1;A:gr  
{ jG E=7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y$Y*%D^w  
break; 7gx 7NDt  
} 7<Yf  
} } vzNh_  
else A><q-`bw  
break; q b[UA5S\`  
} G9YfJ?I  
} YWK|AT-4  
catch(IOException e){e.printStackTrace ();} w y\0o  
catch(Exception e){e.printStackTrace ();} yPmo@aw]1  
cU[^[;4J<  
C@ns`Eh8w  
Utility.log(nFileLength); ElK7jWJ+  
kgl7l?|O  
L T2UY*  
return nFileLength; dln1JZ!  
} )<+t#5"  
)UoF*vC(  
:p|wo"=@Ge  
//保存下载信息(文件指针位置) vTk\6o q  
private void write_nPos() Bokpvd-c7  
{ 2|re4  
try{ bgNN0,+8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); h@H8oZ[  
output.writeInt(nStartPos.length); s-[v[w'E  
for(int i=0;i<nStartPos.length;i++) )/vse5EG+  
{ e%wzcn  
// output.writeLong(nPos); CBrC   
output.writeLong(fileSplitterFetch.nStartPos); R2` -*PZ_  
output.writeLong(fileSplitterFetch.nEndPos); _=Eb:n+X  
} dJ|/.J$d  
output.close(); zcrM3`Zh  
} _s%;GWj  
catch(IOException e){e.printStackTrace ();} n]Z() "D  
catch(Exception e){e.printStackTrace ();} "pa2,-&  
} Gp.XTz#=  
8rEUZk  
N0POyd/rL  
//读取保存的下载信息(文件指针位置) ,jc')#]9B  
private void read_nPos() ^8q(_#w`K  
{ 9ZVzIv(   
try{ a^5.gfzA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %={[e`,  
int nCount = input.readInt(); DKnlbl1^?  
nStartPos = new long[nCount]; N\nxo0sl  
nEndPos = new long[nCount];  nPRv.h  
for(int i=0;i<nStartPos.length;i++) U-6pia /o  
{ 3X>x`  
nStartPos = input.readLong(); W3E7y?  
nEndPos = input.readLong(); (/;<K$u*h  
} $eU oFa5A  
input.close(); nb|KIW  
} Py^fWQ5I~%  
catch(IOException e){e.printStackTrace ();} Iss)7I  
catch(Exception e){e.printStackTrace ();} e{6I-5`|,#  
} &WV&_z  
S"Z.M _  
g=)OcTd#  
private void processErrorCode(int nErrorCode) ;QS(`SK l  
{ <oKoz0!  
System.err.println("Error Code : " + nErrorCode); 1{Kv  
} /JGET  
z?M_Cz;:J  
`"s*'P398  
//停止文件下载 G 5!J9@Yi  
public void siteStop() [yn\O=%5  
{ 3IyNnm=u  
bStop = true; Bbj%RF2,  
for(int i=0;i<nStartPos.length;i++)  c_ Dg0  
fileSplitterFetch.splitterStop(); uWjSqyb:  
}v4T&/vt-  
(`)ZR %i  
} $_Kcm"oj  
} */)O8`}2  
//负责部分文件的抓取 =pnMV"'9  
**FileSplitterFetch.java Y9r##r+  
*/ nAT,y9&  
package NetFox; VBq|j"o0"  
k%Wj+\93 f  
,ui=Wi1  
import java.io.*; 1a]QNl_x  
import java.net.*; p6AF16*f0  
EGw;IFj)  
R|'ftFebB.  
public class FileSplitterFetch extends Thread { wmDO^}>ZP  
+[B@83  
,TlYQ/j%h  
String sURL; //File URL 5MHc gzyp  
long nStartPos; //File Snippet Start Position E@/* eJ  
long nEndPos; //File Snippet End Position 4'# ?"I  
int nThreadID; //Thread's ID Y_= ]w1  
boolean bDownOver = false; //Downing is over wB+X@AA  
boolean bStop = false; //Stop identical :um]a70  
FileAccessI fileAccessI = null; //File Access interface 1)t*l;.  
CNl @8&R  
z2U^z*n{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,!vI@>nhG  
{ {v}BtZ  
this.sURL = sURL; (Tv~$\=  
this.nStartPos = nStart; TOw;P:-  
this.nEndPos = nEnd; ,lDOo+eE%:  
nThreadID = id; =:*2t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *X\J[$!  
} b_w(F_0  
@ MKf$O4K  
HlOn=>)<  
public void run() ?+G / 5,e  
{ '1"vwXJ"  
while(nStartPos < nEndPos && !bStop) dZ|x `bIgs  
{ Q" G;L  
j@.^3:  
O39f  
try{ .~,=?aq^  
URL url = new URL(sURL); ']U<R=5T$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V*gh"gZ<  
httpConnection.setRequestProperty("User-Agent","NetFox"); SNc$!  
String sProperty = "bytes="+nStartPos+"-"; $1Qcz,4B|  
httpConnection.setRequestProperty("RANGE",sProperty); }v6@yU  
Utility.log(sProperty); @tlWyUju  
|ITh2m  
Ejj+%)n.  
InputStream input = httpConnection.getInputStream(); s"~3.J  
//logResponseHead(httpConnection); -"6Z@8=  
#|/ +znJm  
r2m&z%N &  
byte[] b = new byte[1024]; 6t4Khiwx  
int nRead; e.WKf,e"X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .u:aX$t+  
{ CU@}{}Yl  
nStartPos += fileAccessI.write(b,0,nRead); @?*; -]#)  
//if(nThreadID == 1) SBg|V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kD}vK+  
} jI%glO'2  
^s\T<;  
YySo%\d  
Utility.log("Thread " + nThreadID + " is over!"); '"T9y=9]s  
bDownOver = true; *p0Kw>  
//nPos = fileAccessI.write (b,0,nRead); Sym}#F\s  
} ]]P@*4!  
catch(Exception e){e.printStackTrace ();} 4"veqrC  
} ` <u2 N  
} @H$Sv   
1E=E ?$9sg  
kS4YxtvB  
//打印回应的头信息 sGx3O i   
public void logResponseHead(HttpURLConnection con) VIg6'  
{ a U*}.{<!  
for(int i=1;;i++) P=.~LZZ]89  
{ B.:1fT7lI  
String header=con.getHeaderFieldKey(i); 3mhjwgP<nn  
if(header!=null) SqZ .}s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :eIQF7-  
Utility.log(header+" : "+con.getHeaderField(header)); v.hQ 9#:  
else xlH3t&i7  
break; 5\}E4y  
} $\q.Zb  
} e,MgR\F}  
kH`?^ ^_yJ  
x[xRqC vL  
public void splitterStop() 4s@Tn>%SP  
{ 5?[hr5E.E  
bStop = true; >+DM TV[O  
} WF:4p]0~)  
V9jxmu F,  
%/ "yt}"|  
} Q\>mg*79  
FY`t7_Y?GV  
+X`&VO6~  
/* R{ udV  
**FileAccess.java Tv6y +l  
*//文件访问(定位,写) 9bhubx\^/  
package NetFox; (\o4 c0UzK  
import java.io.*; *Q#oV}D_  
q]Kv.x]$R  
w O Ou/Y  
public class FileAccessI implements Serializable{ UyFC\vQ  
+d7 Arg!m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aKE`nA0\B  
RandomAccessFile oSavedFile; `"hWbmQ  
long nPos; ydA@@C\&  
97~>gFU77#  
B&_Z&H=  
public FileAccessI() throws IOException I0qJr2[X~  
{ I1rB,%p  
this("",0); ;&'ryYrex  
} .FV^hrJxI;  
9dm<(I}  
}Q@~_3,UJ  
public FileAccessI(String sName,long nPos) throws IOException ^;F5ymb3U  
{ Xvoz4'Gme  
oSavedFile = new RandomAccessFile(sName,"rw"); 1Wiz0X/  
this.nPos = nPos; wS+!>Q_]w  
oSavedFile.seek(nPos); b- bvkPN  
} 5SZa, +]  
'IT]VRObP  
W;l0GxOxQ  
public synchronized int write(byte[] b,int nStart,int nLen) qHtIjtt[q  
{ Z} t^i^u  
int n = -1; 0Lb{HLT  
try{ TD%L`Gk  
oSavedFile.write(b,nStart,nLen); ,LP^v'[V7  
n = nLen; \Rb:t}  
} &,=FPlTC=  
catch(IOException e) I>##iiKN  
{ 7 \[fjCg\w  
e.printStackTrace (); a2ho+TwT  
} $rTb'8  
8Lgm50bs  
7=5eLc^  
return n; QleVW  
} z@w}+fYO  
JZ~wacDd  
Yi)s=Q:  
} 3~V .  
Lis>Qr  
13w(Tf  
/* 4T; <`{]  
**SiteInfoBean.java HTz`$9  
*/ 0 x' d^  
package NetFox; d0C _:_  
U]w"T{;@.)  
KV$4}{  
public class SiteInfoBean { t1"#L_<e  
Zd%wX<hU"  
V"'PA-z3  
private String sSiteURL; //Site's URL p Pag@L  
private String sFilePath; //Saved File's Path E/*&'Osq  
private String sFileName; //Saved File's Name (x?Tjyzw  
private int nSplitter; //Count of Splited Downloading File 9thG4T8  
psc Fb$b  
i;s;:{cn  
public SiteInfoBean() HyOrAv <  
{//nSplitter的缺省值为5 Jj\lF*B  
//default value of nSplitter is 5 awvP;F?q|  
this("","","",5); @6UZC-M0  
} 8D,*_p  
&"I csxG  
2%6 >)|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R dwt4A+  
{ ^jUw4Dj~-q  
sSiteURL= sURL; PgGUs4[  
sFilePath = sPath; %''L7o.#a  
sFileName = sName; mo] l_'  
this.nSplitter = nSpiltter; EApbaS}Up  
5ya^k{`+ZO  
vp.?$(L^@/  
} 4#7*B yvf  
QIlZZ  
OG$v"Yf~  
public String getSSiteURL() @\XeRx;  
{ Ie(.T2K  
return sSiteURL; _MLf58  
} "om7 : d  
3)6-S  
FMI1[|:;  
public void setSSiteURL(String value) lw[c+F7  
{ FKu8R%9xn%  
sSiteURL = value; o|xZ?#^h  
} dFDf/tH  
6}e*!,2Xj  
pr7lm5  
public String getSFilePath() qP<D9k>  
{ SY[3O  
return sFilePath; 3X11Gl  
} XD|g G  
|:JT+a1  
&KAe+~aPm  
public void setSFilePath(String value) ZV+tHgzlv5  
{ :v;U7  
sFilePath = value; ~IjID  
} _p+E(i 9  
5Gy#$'kdf  
"t(_r@qU/  
public String getSFileName() RR ^7/-  
{ DyiJ4m}kh  
return sFileName; `o295eiY(b  
} la_c:#ho  
C!Srv 7  
\3^ue0  
public void setSFileName(String value) 1O NkmVtL  
{ gCC7L(1  
sFileName = value; t(-,mw  
} zU+q03l8Ur  
0 }od Q#  
_ `&l46  
public int getNSplitter() n+hL/aQ+  
{ 0V(}Zj>  
return nSplitter; Zx_ ^P:rL  
} "O<ETHd0  
2~?E'  
PWiUW{7z  
public void setNSplitter(int nCount) L*[3rqER  
{ Yg3nT:K_Y&  
nSplitter = nCount; W_JO~P  
} y^`JWs,  
} ?SElJ? Z  
`HkNO@N[  
3u$1W@T(  
/* CssE8p>"F  
**Utility.java J:glJ'4E  
*/ ,r;xH}tbi  
package NetFox; 6{HCF-cQd  
u"*DI=pwb  
Wu/#}Bw#  
public class Utility { l[ $bn!_ e  
& rab,I"  
1VlU'qY  
public Utility() fM4B.45j  
{ I*3}erT  
y"q>}5  
_7<{+Zzm  
} jxkjPf?  
s{yw1:  
//线程睡眠 %}VH5s9\  
public static void sleep(int nSecond) 3S7"P$q  
{ z77>W}d  
try{ }0Ns&6)xG  
Thread.sleep(nSecond); aYb97}kI  
} ?V^7`3F  
catch(Exception e) qz>R"pj0g  
{ GgG #]a!_f  
e.printStackTrace (); ()l3X.t,$  
} +lqGf  
} ji1vLu4|t  
C$1W+(  
//日志 ]>VG}e~b  
public static void log(String sMsg) >- \bLr  
{ r.\L@Y<  
System.err.println(sMsg); K8&;B)VT>  
} % (y{Sca  
Bso#+v5  
A,cXN1V  
public static void log(int sMsg) qGV_oa74  
{ j/d}B_2  
System.err.println(sMsg); y]fI7nu&  
} gE#'Zv{7  
} KZw~Ch}b9  
g gx_h  
\xCCJWek  
/* h&$h<zL[  
**TestMethod.java yEI@^8]s  
*/ ezp%8IZ;  
package NetFox; ^0OP&s;"  
lbBWOx/|  
}Ze*/ p-  
public class TestMethod { LD}~]  
]$[sfPKA  
"a8E0b  
public TestMethod() nOGTeKjEJ  
{ ///xx/weblogic60b2_win.exe jRS{7rx%MH  
try{ WI/tWj0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !ka* rd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3uqhYT;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ww2@!ng  
fileFetch.start(); _xp8*2~-  
} Mz(Vf1pi%  
catch(Exception e){e.printStackTrace ();} ?1SsF>|  
+y?Ilkk;j  
Z,.Hz\y1D  
} WR"D7{>tw  
YOD.y!.zq7  
TQF+aP8[L  
public static void main(String[] args) \:WWrY8&  
{ qJrT  
new TestMethod(); c>B1cR  
} :x*)o+  
} T`ibulp  
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