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http断点续传简单实现(java)

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/* VyK]:n<5Q  
**SiteFileFetch.java F-Mf~+=Dn  
*/ ?,e7v.b  
package NetFox; eaP,MkK&  
import java.io.*; ,aS6|~ac4  
import java.net.*; 9?B}CCE<LR  
?_36uJo}  
+@D [%l|  
public class SiteFileFetch extends Thread { /NFv?~</k  
cy|]}n85  
i6wLM-.)  
SiteInfoBean siteInfoBean = null; //文件信息Bean tcOgF:  
long[] nStartPos; //开始位置 v3 4!rL  
long[] nEndPos; //结束位置 nTO,d$!Kp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0eq="|n^|  
long nFileLength; //文件长度 Z 4NNrA#  
boolean bFirst = true; //是否第一次取文件 ]~~PD?jh  
boolean bStop = false; //停止标志 0/?V _  
File tmpFile; //文件下载的临时信息 @czNiWU"4;  
DataOutputStream output; //输出到文件的输出流 KK" uSC  
cn (-{dCXM  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ZrJAfd\5c  
public SiteFileFetch(SiteInfoBean bean) throws IOException BeZr5I"`}  
{ 6QVdnXoG/  
siteInfoBean = bean; *BzqAi0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9:zW$Gt&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c6gRXp'ID  
if(tmpFile.exists ()) O'y8[<  
{ o= VzVg  
bFirst = false; 6|gC##T  
read_nPos(); h-u63b1"?  
} n'a=@/  
else ]5W|^%  
{ 2lNZwV7  
nStartPos = new long[bean.getNSplitter()]; MKIX(r( |  
nEndPos = new long[bean.getNSplitter()]; ^g/    
} #DjSS.iW  
-Z )j"J  
LAqmM3{fA  
"HI&dC  
} UMsJg7~  
Y?Ph%i2E  
/c 3A>  
public void run() V'TBt=!=]  
{ tow0/ Jt  
//获得文件长度 :D(4HXHK%  
//分割文件 h:{rjXK  
//实例FileSplitterFetch e7X#C)  
//启动FileSplitterFetch线程 Ce 3{KGBw  
//等待子线程返回 HD^Ou5YB  
try{ It$'6HV~Sb  
if(bFirst) ph*9,\c8  
{ .bcoH  
nFileLength = getFileSize(); [JI>e;l C:  
if(nFileLength == -1) B->3/dp2c'  
{ ;!H<W[  
System.err.println("File Length is not known!"); GZY8%.1{"a  
} :&*Y Io  
else if(nFileLength == -2) y(gL.08<  
{ zJC!MeN  
System.err.println("File is not access!"); iZsZSW \  
} (bpO>4(S  
else 88%7  
{ iveJh2!#<  
for(int i=0;i<nStartPos.length;i++) xz!b@5DR'%  
{ )UBU|uYR\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o< )"\f/,  
} 9g %1^$R  
for(int i=0;i<nEndPos.length-1;i++) *4]u?R  
{ 5q<cZ)v#&  
nEndPos = nStartPos[i+1]; Y#aL]LxZE  
} m/ D ~D~  
nEndPos[nEndPos.length-1] = nFileLength; %H)^k${  
} IXjFK  
} "cJ))v-'  
}STTDq4  
&6 ymGo  
//启动子线程 (<bYoWrK#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2bu,_<K.  
for(int i=0;i<nStartPos.length;i++) <V[Qs3uo(  
{ j!1 :+H_L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FM{^ND9x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 244[a] %&;  
nStartPos,nEndPos,i); \mK;BWg)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q4y P\B  
fileSplitterFetch.start(); =()Vrk|uK  
} `kE ;V!n?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <8J_[ S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -BV8,1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }Gvu!a#R  
nEndPos = " + nFileLength); G 6r2 "  
// fileSplitterFetch[nPos.length-1].start(); d76nyQKK  
`jHbA#sO  
.}n-N #  
//等待子线程结束 #gq!L  
//int count = 0; I$0O4  
//是否结束while循环 u~pBMg ,  
boolean breakWhile = false; 4Tdp;n\F  
yg@8&;bP`  
4UxxmREx;  
while(!bStop) }Fq~!D Ee  
{ i!<1&{  
write_nPos(); ^RI& `5g  
Utility.sleep(500); SSQB1c  
breakWhile = true; [r#m +R"N  
TSKT6_IJw  
[d?tf  
for(int i=0;i<nStartPos.length;i++) S+ 3l X7  
{ 73p7]Uo  
if(!fileSplitterFetch.bDownOver) '.B5CQ  
{ '< .gKo  
breakWhile = false; |Cm6RH$(  
break; ?hmuAgOtbh  
} cjp~I/U  
} ~K/_51O'  
if(breakWhile) gyz_$T@x  
break; dW5@Z-9  
|!q,J  
}?)U`zF)7}  
//count++; *'cyFu$  
//if(count>4) (V x2*Aw]  
// siteStop(); OLZs}N+;]  
} k>)Uyw$!  
.<zN/&MXf  
C=Tq/L w  
System.err.println("文件下载结束!");  JfsvK2I  
} ]!X[[w)  
catch(Exception e){e.printStackTrace ();} Bra}HjHO  
} 2!_DkE  
Y#t9DhzFWo  
oZ_,WwnE  
//获得文件长度 m-2!r*(zt  
public long getFileSize() ,m Nd#  
{ TD sjNFe3  
int nFileLength = -1; RT. %\)))  
try{ YU`}T<;bg  
URL url = new URL(siteInfoBean.getSSiteURL()); n-u HKBq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); / K(l[M  
httpConnection.setRequestProperty("User-Agent","NetFox"); /Un\P   
< V*/1{  
GOsOFs"I  
int responseCode=httpConnection.getResponseCode(); skYHPwJdW  
if(responseCode>=400) )UtK9;@"  
{ R; ui 4wg6  
processErrorCode(responseCode); T/PmT:Qg `  
return -2; //-2 represent access is error QM'|k6  
} \UP=pT@  
\S_A e;  
0a2#36;_IK  
String sHeader; V aoqI  
^-Rqlr,F;  
1k]L,CX  
for(int i=1;;i++) "rrw~  
{ {"2Hv;x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `GSl}A  
//Utility.log(in.readLine()); DX^8w?t  
sHeader=httpConnection.getHeaderFieldKey(i); K 6yD64  
if(sHeader!=null) 'jXJ!GFw  
{ ;9Qxq]  
if(sHeader.equals("Content-Length")) @?jbah#  
{ azzG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); oE_*hp+  
break; 2tg07  
} }mo)OyIX  
} }KYOde@  
else _f~$iY  
break; xSqr=^  
} KF1Zy;  
} lvRTy|%[  
catch(IOException e){e.printStackTrace ();} njaKU?6%d2  
catch(Exception e){e.printStackTrace ();} #Cx#U"~G`  
M~h.M PI  
CED[\ n  
Utility.log(nFileLength); Z&4L///  
]a`"O  
YhzDw8f  
return nFileLength; 8;"9A  
} ;Ea8>  
}]M'f:%b  
;n.h!wmJ}  
//保存下载信息(文件指针位置) F vTswM>  
private void write_nPos() z7z9lDS  
{ H )>3c1  
try{ HRJ\H- V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B873UN  
output.writeInt(nStartPos.length); r,3\32[?  
for(int i=0;i<nStartPos.length;i++) ?D,j!Hy  
{ D>^g2!b:  
// output.writeLong(nPos); XZS%az1%  
output.writeLong(fileSplitterFetch.nStartPos); ;at1|E*  
output.writeLong(fileSplitterFetch.nEndPos); '? -N  
} x}O,xquY  
output.close(); .beqfcj"  
} &*E! %57  
catch(IOException e){e.printStackTrace ();} 2.=G  
catch(Exception e){e.printStackTrace ();} zk!7TUZ">w  
} WJ)4rQ$o  
sxS%1hp3  
k ]T  
//读取保存的下载信息(文件指针位置) jse!EtB:  
private void read_nPos() WgG$ r  
{ Um4DVg5  
try{ $RB p!7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0rQ r#0`  
int nCount = input.readInt(); "'GhE+>Z  
nStartPos = new long[nCount]; Q, "8Ty  
nEndPos = new long[nCount]; f& \ Bs8la  
for(int i=0;i<nStartPos.length;i++) ]5K(}95&'  
{ *z#du*f[  
nStartPos = input.readLong(); )m[<lJ bw  
nEndPos = input.readLong(); ^fyue~9u  
} ,KD?kSIf  
input.close(); | lZJt  
} Fa\jVFIQ  
catch(IOException e){e.printStackTrace ();} ?Z4%u8Krvz  
catch(Exception e){e.printStackTrace ();} Vy|4k2  
} Rry] 6(  
-rjQ^ze  
k4!_(X%8  
private void processErrorCode(int nErrorCode) V1GkX =H},  
{ 4*9t:D|}  
System.err.println("Error Code : " + nErrorCode); lzz;L z  
} )v11j.D  
ms!|a_H7 r  
ywkRH  
//停止文件下载 m2YsE  j7  
public void siteStop() U* c'xoP  
{ fL d2{jI,  
bStop = true; Rjlp<  
for(int i=0;i<nStartPos.length;i++) r b\t0tg  
fileSplitterFetch.splitterStop(); 2_6ON   
h:U#F )  
aG]^8`~>'  
} }%jpqip  
} 1X`,7B@pz  
//负责部分文件的抓取 bq8Wvlv04  
**FileSplitterFetch.java >M!LC  
*/ Jw&Fox7p  
package NetFox; Ziub%C[oV  
(fr=N5   
^c >Bh[  
import java.io.*; ;"ESN)*|i  
import java.net.*; ]NI CQ9  
<5 OUk  
:vx<m_  
public class FileSplitterFetch extends Thread { T9!NuKfur  
om9'A=ZU  
lKQevoy'  
String sURL; //File URL c#`IF6qj  
long nStartPos; //File Snippet Start Position dFhyT.Y?  
long nEndPos; //File Snippet End Position m[iQ7/  
int nThreadID; //Thread's ID md? cvGDE  
boolean bDownOver = false; //Downing is over #qR6TM&;  
boolean bStop = false; //Stop identical 5XzsqeG|  
FileAccessI fileAccessI = null; //File Access interface A+frKoi  
ZZHzC+O#^  
Iz'Et'w8!  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException sKsMF:|OT  
{ @iXBy:@  
this.sURL = sURL; a j$& 9][  
this.nStartPos = nStart; ?*yB&(a:8  
this.nEndPos = nEnd; aI ;$N|]u  
nThreadID = id; QtXiUx^ k<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vD:J!|hs(  
} : ir3u  
YTmHht{j#  
\%bJXTK&W  
public void run() @Tq-3Um  
{ Lj#xZ!mQS  
while(nStartPos < nEndPos && !bStop) qO8:|q1%;\  
{ V/#J>-os}W  
Iz j-,a  
5 r_Z3/%  
try{ 6&0G'PMf  
URL url = new URL(sURL); +]( y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?6nB=B)/  
httpConnection.setRequestProperty("User-Agent","NetFox"); zS|4@t\__  
String sProperty = "bytes="+nStartPos+"-"; JC-> eY"O2  
httpConnection.setRequestProperty("RANGE",sProperty); C& XPn;f  
Utility.log(sProperty); L-S5@;"  
_KkaseR  
XqUQ{^;aI  
InputStream input = httpConnection.getInputStream(); ov H'_'  
//logResponseHead(httpConnection); izGU&VeB  
b]Kb ~y|  
<uJ {>~  
byte[] b = new byte[1024]; 3!/J!X3L  
int nRead; TQNdBq5I6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5}Ge  
{ +!px+*)bW  
nStartPos += fileAccessI.write(b,0,nRead); "v`q%(TA  
//if(nThreadID == 1) *i#N50k*j'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (|o @  
} $gz8! f?  
4F0w+w JD  
z;2& d<h  
Utility.log("Thread " + nThreadID + " is over!"); yufw}Lo-  
bDownOver = true; .d[ ^&<^  
//nPos = fileAccessI.write (b,0,nRead); );TB(PQsBT  
} %mU$]^Tw(  
catch(Exception e){e.printStackTrace ();} P]y{3y:XxM  
} NIQ}+xpC  
} F%&lM[N%  
":qHDL3  
C;/ONF   
//打印回应的头信息 &8Vh3QLEx  
public void logResponseHead(HttpURLConnection con) 1y6<gptx  
{ ^E\n^D-RV  
for(int i=1;;i++) B hx.q,X  
{ ~vA8I#.  
String header=con.getHeaderFieldKey(i); *S}CiwW>/  
if(header!=null) islHtX VE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x7^VU5w#  
Utility.log(header+" : "+con.getHeaderField(header)); qUmSB"#Z  
else a?GXVQ  
break; m-tn|m!J  
} H Q[  
} Opg_-Bf  
||TZ[l  
?SO!INJ  
public void splitterStop() j7a }<\  
{ O/ItN5B ;  
bStop = true; st)v'ce,  
} %g5#q64  
>b9J!'G,(  
5[B)U">]  
} OvwoU=u  
[bX ^_ Y  
FW;}S9u3  
/* SB('Nqih  
**FileAccess.java }|) N5bGQe  
*//文件访问(定位,写) L aA<`  
package NetFox; .{?; #Cdn  
import java.io.*; PZ'|)  
%(6+{'j~#  
BQ[R)o  
public class FileAccessI implements Serializable{ 9ei'oZ  
B=^M& {  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 g@M5_I(W  
RandomAccessFile oSavedFile; :8}Qt^p  
long nPos; e:4,rfF1  
kCz2uG)l  
i?@7>Ca  
public FileAccessI() throws IOException 3Rsrb  
{ TC'SDDX  
this("",0); v^Fu/Y  
} 33eOM(`D[  
{6Nbar@3  
Gl3g.`X{$@  
public FileAccessI(String sName,long nPos) throws IOException 5eF tcK  
{ dQ_'8 )  
oSavedFile = new RandomAccessFile(sName,"rw"); \Wppl,"6c  
this.nPos = nPos; s?1Aj<  
oSavedFile.seek(nPos); l?m 3 *  
} jpR]V86G  
'x? |tKzd  
8p}z~\J{a:  
public synchronized int write(byte[] b,int nStart,int nLen) .`J*l=u$  
{ [h' 22 W  
int n = -1; iK1{SgXrFI  
try{ D,FgX/&i/  
oSavedFile.write(b,nStart,nLen); Ygg(qB1q  
n = nLen; .}+3A~  
} 4$N,|bt  
catch(IOException e) #wvGS%  
{ ^e =xEZD  
e.printStackTrace (); m432,8 K3r  
} =)i^E9  
+gBD E :  
3^q9ll7Op  
return n; =Ov,7<8o  
} Y4,p_6aKJ]  
Zg4wd/y?  
eej#14 &  
} tx+P@9M_Aq  
eDNY|}$}v  
8<Yv:8%B6  
/* 4 PU@W o  
**SiteInfoBean.java lY,9bSF$  
*/ MDd 2B9cy[  
package NetFox; 3qNuv];2  
@RoU   
@ZV>Cl@%2  
public class SiteInfoBean { ?,hGKSC  
KlBT9"6"  
AtAu$"ue  
private String sSiteURL; //Site's URL ]:?hU^H]<  
private String sFilePath; //Saved File's Path n36@&q+B&  
private String sFileName; //Saved File's Name \sW>Y#9]  
private int nSplitter; //Count of Splited Downloading File ~e){2_J&n  
+8|Xj!!*}  
,~l4-x.,  
public SiteInfoBean() | ObA=[j  
{//nSplitter的缺省值为5 )B~{G\jS  
//default value of nSplitter is 5 @fVz *  
this("","","",5); 'q8:1i9\[  
} }ri7@HCY4  
irB}h!@  
;\/ RgN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {K/xI  
{ ;1TQr3w  
sSiteURL= sURL; << YH4}wZ  
sFilePath = sPath; |oR{c%z05  
sFileName = sName; Zjc 0R   
this.nSplitter = nSpiltter; "88<{xL  
2&o3OKt  
S^i<_?nwg  
} =}SC .E\  
bD 1IY1  
2)q$HUIX  
public String getSSiteURL() nqcD#HUv  
{ = o1&.v2j  
return sSiteURL; >lO]/3j1  
} P>*`<$FR  
w~e$ul(IQM  
Jy]}'eE?pr  
public void setSSiteURL(String value) M>jk"*hA|  
{ ?SoRi</1  
sSiteURL = value; 6bbzgULl  
} nh"LdHqiDB  
`hU 2Ss~  
QUc&f+~  
public String getSFilePath() ^JB5-EtL(  
{ }/%^;@q;  
return sFilePath; 2wYY0=k2  
} D}pN sQ  
lXrAsm$  
'c/Z W  
public void setSFilePath(String value) H3BMN}K~  
{ m'L8z fX  
sFilePath = value; J|WkPv2  
} /p[lOg  
SBG.t:  
Z<[f81hE&  
public String getSFileName() _/a8X:[(  
{ 6^Ax3# q  
return sFileName; :*E#w"$,j  
} "]1|%j  
`bRt_XGPmF  
]1i1_AR'`  
public void setSFileName(String value) N51RBA  
{ K<D=QweOon  
sFileName = value; !>QD42  
} '0E^th#u-0  
A>Oi9%OY:  
vip& b}u  
public int getNSplitter() CXhE+oS5z'  
{ H7R6Ljd?&S  
return nSplitter; $_0~Jzt,  
} Ni) /L( &  
81 /t)Cp  
Z3Y(g  
public void setNSplitter(int nCount) c/ABBvd|  
{ m}>#s3KPA  
nSplitter = nCount; }6^d/nE*T  
} t"L-9kCM  
} aMycvYzH  
-H(\[{3{V  
d#]XyN>  
/* lDm0O)Dh!  
**Utility.java Hwm] l`E]  
*/ A +J&(7N  
package NetFox; ~^pV>>LX|  
[qGj*`@C  
bB`p-1  
public class Utility { %nkP?gn"a  
('7qJkV  
c$[cDf~  
public Utility() Qt+;b  
{ c O[Hr  
\ZPmPu9^(  
7`IoQvX  
} BYBf`F)4  
%qf ?_2v  
//线程睡眠 Tf1G827  
public static void sleep(int nSecond) G`1FD  
{ r#CQCq  
try{ o> i`Jq&  
Thread.sleep(nSecond); vw/L|b7G  
} a J&)-ge  
catch(Exception e) @L ,hA v ^  
{ |wFfVDp  
e.printStackTrace (); fxKhe[;  
} k;bdzcMkQ  
} QC+K:jL  
 A/zZ%h  
//日志 O!7v&$]1  
public static void log(String sMsg) @ !UuK;  
{ nA#FGfZ{Ge  
System.err.println(sMsg); :t36]NM  
} bm+ #OI  
KkJK5dZo  
=83FCq"  
public static void log(int sMsg) L\u6EMyV  
{ ; n)9  
System.err.println(sMsg); nYc8+5CcK'  
} */ ~_3  
} vl{G;[6  
XsVp7zk\  
TC%ENxDR  
/* ]N\J~Gm  
**TestMethod.java 6!eI=h2P  
*/ X?'v FC  
package NetFox; ,a&&y0,  
Sl?@c/Ng  
k_^| %xJ  
public class TestMethod { X<OOgC  
g=T !fF=  
k{?Pgf27  
public TestMethod() /i${[1  
{ ///xx/weblogic60b2_win.exe [-*1M4D9  
try{ ># {,(8\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2,nVo^13}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1${lHVx]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ws tH&^  
fileFetch.start(); Oc|`<^m  
} )_vE"ryThA  
catch(Exception e){e.printStackTrace ();} 23F<f+2S  
v7i5R !  
/qYo*S_cG  
} /ynvQ1#uA  
XpFo SW#K  
jP]I>Tq  
public static void main(String[] args) ^X&n-ui   
{ ymIjm0jVh  
new TestMethod(); ^sWsP`DV  
} _x.<Zc\x  
} KNkVI K  
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