http断点续传简单实现（java)

/* hB!>*AsG  
**SiteFileFetch.java *(?tf{  
*/ $*KM%M6  
package NetFox; /qKO9M5A  
import java.io.*; y5p)z"  
import java.net.*; "8NhrUX  
:c_>(~  
Z{MR#.I  
public class SiteFileFetch extends Thread { LGau!\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u>K(m))5W3  
long[] nStartPos; //开始位置 4U;Zs3  
long[] nEndPos; //结束位置 0+iaO"%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?k}"g$JFn  
long nFileLength; //文件长度 8Hf:yG,  
boolean bFirst = true; //是否第一次取文件 Uyuvmt>  
boolean bStop = false; //停止标志 (oUh:w.]Gw  
File tmpFile; //文件下载的临时信息 e2}5< 7  
DataOutputStream output; //输出到文件的输出流 4GL-3e  
Y*KP1=Md  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6>hW.aq}  
public SiteFileFetch(SiteInfoBean bean) throws IOException HRG2sv T4t  
{ CY
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siteInfoBean = bean; $YPU(y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HQ7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /}ADV2sF  
if(tmpFile.exists ()) A_ftf7,  
{ -(Z%?]+  
bFirst = false; T1([P!
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read_nPos(); /Cl=;^)  
} pO10L`|  
else d~>d\K%v  
{ ^@4$O|3Wh'  
nStartPos = new long[bean.getNSplitter()]; H[u
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nEndPos = new long[bean.getNSplitter()]; #C`IfP./  
} m|c5X)}-  
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l)d(N7HME  
x=7qC#+)  
} Wpdn^=dhL  
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public void run() `yvH0B -  
{ e*Y>+*2y  
//获得文件长度 )
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//分割文件 n{@^ne4m  
//实例FileSplitterFetch .O1Kwu  
//启动FileSplitterFetch线程 k
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//等待子线程返回 
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try{ aOOkC&%  
if(bFirst) mT3'kUZ}]  
{ z+=wql*Eo  
nFileLength = getFileSize(); 6z-&Zu7@  
if(nFileLength == -1) >}p'E9J?r  
{ jW!x!8=  
System.err.println("File Length is not known!"); 5RUhrE   
} u~-,kF@  
else if(nFileLength == -2) c[6=&  
{ Rr!oT?6J?  
System.err.println("File is not access!"); Pi!3wy  
} DEFh&n  
else zg[.Pws:E  
{ 1%^d<%,]  
for(int i=0;i<nStartPos.length;i++) jW<aAd  
{ )d^b\On  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SR<*y

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} Ia'm9Z*  
for(int i=0;i<nEndPos.length-1;i++) 0\X'a}8Bu  
{ >(9"D8  
nEndPos = nStartPos[i+1]; ?04$1n:  
} EYaX@|)  
nEndPos[nEndPos.length-1] = nFileLength; /DC\F5 G  
} X^%E"{!nU  
} Aq5@k\[  
%ylpn7I\6  
:8CYTEc  
//启动子线程 Ev)a
XP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \U
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for(int i=0;i<nStartPos.length;i++) 7Gs0DwV  
{ ;/-X;!a>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1f/8XxTB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KD*q|?Z  
nStartPos,nEndPos,i); F,NS:mE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ss4<s 5:y  
fileSplitterFetch.start(); flr&+=1?D  
} qUuvM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %(v<aEQtt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @9}SHS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !vQDPLBL  
nEndPos = " + nFileLength); 4pw:O^v  
// fileSplitterFetch[nPos.length-1].start(); Rc.8j,]  
.%3qzOrN  
efnj5|JSV  
//等待子线程结束 [h=[@ji
B  
//int count = 0; Q*c |!< &e  
//是否结束while循环 F# a)"$j;  
boolean breakWhile = false; E~| XY9U36  
,iYKtS3  
;A3aUN;"I  
while(!bStop) BGSqfr1F  
{ 5"cYZvGkJ  
write_nPos(); >_m4 idq1  
Utility.sleep(500); @?gN &Z)I  
breakWhile = true; {R{Io|  
;=ci7IT'  
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for(int i=0;i<nStartPos.length;i++) OQC.p,SO  
{ J]=2] oI2  
if(!fileSplitterFetch.bDownOver) w*-1*XNA  
{ \@eC^D2  
breakWhile = false; o@!!I w  
break; ==W`qC4n?n  
} HbUadPr  
} $S(q;Y  
if(breakWhile) ]L?DV3N  
break; :87HXz6]jS  
wsg u# as|  
G1`H H&  
//count++; F87aIJ.pGN  
//if(count>4) wwI'n*Q'$  
// siteStop(); ap% Y}  
} h4 X>  
$>M A  
3~uWrZ.u  
System.err.println("文件下载结束！"); _hy<11S;  
} O:
>9yZhV  
catch(Exception e){e.printStackTrace ();} x.:k0;%Q  
} Hswgv$n  
9"RGf 1]  
n!>#o1Qr  
//获得文件长度 ?4&C)[^  
public long getFileSize() cYafQyU  
{ 61}hB>TT:  
int nFileLength = -1; $[NC$*N7  
try{ :+nECk 
 
URL url = new URL(siteInfoBean.getSSiteURL()); }K%y'D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #ivN-WKCl  
httpConnection.setRequestProperty("User-Agent","NetFox"); j& x=?jX  
]*Tnu98G}  
*z{.9z`  
int responseCode=httpConnection.getResponseCode(); ~LKX2Q:S  
if(responseCode>=400) )ZP-t!).G#  
{ >aaHN1Ca  
processErrorCode(responseCode); _H(:$=$Q  
return -2; //-2 represent access is error HR> X@g<c  
} [61T$.  
WV8?zB1  
ZGHh!Ds;  
String sHeader; NL-<K  
XJ.ERLR.  
.bT|:Q~@{  
for(int i=1;;i++) H|K}m,g  
{ =%Yw;%0)Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yN Bb(!u  
//Utility.log(in.readLine()); -UhGacw  
sHeader=httpConnection.getHeaderFieldKey(i); IRxFcLk  
if(sHeader!=null) fjh0Z i45  
{ 1 iWe&I:  
if(sHeader.equals("Content-Length")) 8UANB]@Y}  
{ s7~[7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wB0zFlP  
break; @A-^~LoP.  
} 2\:z 
 
} 51\N+  
else ]("5O V5  
break; Q6r!=yOEY  
} OGjeE4  
} Q;3v ]h_  
catch(IOException e){e.printStackTrace ();} 4GY:N6qe'  
catch(Exception e){e.printStackTrace ();} UQ ~7,D`=#  
0qV"R7TW  
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Utility.log(nFileLength); 6a=Y_fma  
xzRs;AXOp  
2EdKxw3$]  
return nFileLength; `i
iZ  
} t#p*{S 3u  
eZr}xo@9  
l*yh(3~}  
//保存下载信息（文件指针位置） A>c/q&WUk  
private void write_nPos() >;;tX3(  
{ _cW(R,i  
try{ Yp_R+a^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9b0M'x'W5  
output.writeInt(nStartPos.length); P 3CzX48^  
for(int i=0;i<nStartPos.length;i++) $)5-}NJf'  
{ 5G-}'-
R  
// output.writeLong(nPos); !Hk$ t  
output.writeLong(fileSplitterFetch.nStartPos); LcA~a<_  
output.writeLong(fileSplitterFetch.nEndPos);
}#rdMh  
} 4G%!t`?q  
output.close(); \G}$+  
} DB^"iof
 
catch(IOException e){e.printStackTrace ();} V`n;W6Q17  
catch(Exception e){e.printStackTrace ();} -UPl
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} bwm?\l.A  
6#JdQ[IP6  
wM^_pah#Y5  
//读取保存的下载信息（文件指针位置） ~4Gs\U:!Q  
private void read_nPos() kUdl2["MZ  
{ A!K/92[#@  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 
'Gw;@[  
int nCount = input.readInt(); CulU?-[i  
nStartPos = new long[nCount]; \rw/d5.  
nEndPos = new long[nCount]; iE|qU_2Y  
for(int i=0;i<nStartPos.length;i++) S!<1CFh  
{ =.]>,N`C  
nStartPos = input.readLong(); b$24${*'  
nEndPos = input.readLong(); sp0j2<$a  
} CFW\  
input.close(); }Ot I8;>  
} G$5N8k[2  
catch(IOException e){e.printStackTrace ();} O>E2G]K]\  
catch(Exception e){e.printStackTrace ();} .=VtMi
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} fDn|o"  
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o@o6<OP^  
private void processErrorCode(int nErrorCode) myVV5#{  
{ ~9:ILCfX  
System.err.println("Error Code : " + nErrorCode); Zm:Wig ,a  
} _Gf.1Bsf@S  
l @hXQ/  
pLFJ"3IJB  
//停止文件下载 \k=.w  
public void siteStop() &~u=vuX  
{ 7I6bZ;}d  
bStop = true; PC_#kz  
for(int i=0;i<nStartPos.length;i++) m})q8b!S  
fileSplitterFetch.splitterStop(); %G<!&E!0h  
Sv7_-#SW<(  
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} _)7dy2%{q  
} s7FJJTn  
//负责部分文件的抓取 N F[v/S  
**FileSplitterFetch.java _u`NIpXSP  
*/ s_=/p5\  
package NetFox; ~=Y<B/  
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hSZ0 }/  
import java.io.*; S^GB\uJ  
import java.net.*; 0x}8}  
!9!kb  
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public class FileSplitterFetch extends Thread { +$#YW5wy  
C*}TY)8  

NX$S^Z\QI  
String sURL; //File URL ?I`BbT}  
long nStartPos; //File Snippet Start Position i>9/vwe  
long nEndPos; //File Snippet End Position CjzfU*G  
int nThreadID; //Thread's ID o|7]8K=  
boolean bDownOver = false; //Downing is over rAdYBr=0  
boolean bStop = false; //Stop identical }LH>0v_<Y  
FileAccessI fileAccessI = null; //File Access interface wl{Fx+<^3  
:<OInKE>Cx  
?"p:6%GFz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =?`5n|A*  
{ a2dlz@)J  
this.sURL = sURL; SWjOJjn  
this.nStartPos = nStart; OQ$77]XtvL  
this.nEndPos = nEnd; Jlw oSe:S  
nThreadID = id; ZDZPJp,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lD!o4ZAo  
} $X%GzrN  
1n! JfsU  
APT'2-I_  
public void run() AW8"@  
{ P!C!E/Jf5  
while(nStartPos < nEndPos && !bStop) x@F"ZiYD@O  
{ G 1{F_  
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R|T_9/#)  
try{ M%wj6!5  
URL url = new URL(sURL); BJ3st  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 29K09 0f  
httpConnection.setRequestProperty("User-Agent","NetFox"); td@
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String sProperty = "bytes="+nStartPos+"-"; R>"E Xq  
httpConnection.setRequestProperty("RANGE",sProperty); " }@QL`  
Utility.log(sProperty); E'=~<&  
@WX]K0$;  
kb?QQ\e  
InputStream input = httpConnection.getInputStream(); VT1W#@`e-  
//logResponseHead(httpConnection); YF=@nR$_~j  
k/vE|  
Q)}sX6TB  
byte[] b = new byte[1024]; hq.z:D  
int nRead; cLH|;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x.r~e)x=  
{ t;9f7~  
nStartPos += fileAccessI.write(b,0,nRead); [8/E ;h  
//if(nThreadID == 1) 3LZ0EYVL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @]Ye36v0#L  
} }%EQ  
93%U;0w[Nw  
M:OY8=V  
Utility.log("Thread " + nThreadID + " is over!"); \xk`o5/{  
bDownOver = true; dL<okw  
//nPos = fileAccessI.write (b,0,nRead); >9D=PnHnD  
} 1Y410-.3w{  
catch(Exception e){e.printStackTrace ();} S%b7NK  
} ZoB?F  
} 7-+X -Y?  
"k\W2,q[  
rr2'bf<]  
//打印回应的头信息 B`a5%asJn  
public void logResponseHead(HttpURLConnection con) w .l2  
{
7ZHM;_ -  
for(int i=1;;i++) SX|b0S,  
{ $kJvPwRO  
String header=con.getHeaderFieldKey(i); GLA,,i'i9  
if(header!=null) !3K6ew>Sf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OqDLb  
Utility.log(header+" : "+con.getHeaderField(header)); x+(h#+F  
else Z>Nr"7k  
break; }U'fPYYi8  
} yqqP7  
} :|oH11y  
.:c^G[CQ^9  
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public void splitterStop() 1i9}mzy%  
{ -[~UX!XFM  
bStop = true; G*e/Ft.wf8  
} `9eE139V='  
\1f$]oS  
.l5y!?  
}  %"j<`  
lyKV^7}  
Mw7 ~:O`  
/* GiB3.%R`  
**FileAccess.java gNl@T  
*//文件访问(定位，写) gOa'o<  
package NetFox; PdJtJqA8h\  
import java.io.*; }:YS$'by  
4~4PZ  
y[S5  
public class FileAccessI implements Serializable{ 0R<@*  
G@h6>O  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]i\D*,FfU  
RandomAccessFile oSavedFile; lRnst-inlI  
long nPos; 2t\a/QE)E  
3> -/sii  
|)i-c`x  
public FileAccessI() throws IOException Y1
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{ L.lmbxn  
this("",0); R3wK@D  
} X!,P] G  
YEAiLC+q  
uXW<8( %W  
public FileAccessI(String sName,long nPos) throws IOException w``t"v4  
{ yInW?3  
oSavedFile = new RandomAccessFile(sName,"rw"); BqK|4-Pf  
this.nPos = nPos; aDR<5_Yb  
oSavedFile.seek(nPos); k&ujr:)5Y5  
} ( }5k"9Z  
_Qs)~  
/s uz>o\  
public synchronized int write(byte[] b,int nStart,int nLen) e-H:;m5R  
{ 25*/]iu  
int n = -1; S #%'Vrp  
try{ cC1nC76[  
oSavedFile.write(b,nStart,nLen); H:4r6-{  
n = nLen; 4VSIE"8e  
} %Vrl"4^}t  
catch(IOException e) lh3%2Dq$  
{ ^%|{>Mz;c  
e.printStackTrace (); c, \TL ]  
} V:)k@W?P  
,*a8]L  
qS>P,>C  
return n; OF,<K%A  
} 8 wQV^G  
[oKc<o7)~"  
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} 2X;,s`)  
BgJ;\NV  
/A[AHJ<[?  
/* y _>HQs,:  
**SiteInfoBean.java YN9ug3O+  
*/ %#2[3N{  
package NetFox; S%-L!V ,  
-4Zf0r1u  
:,y V?E6]  
public class SiteInfoBean { d%VGfSrKq  
W@AZ
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G+ Y`65  
private String sSiteURL; //Site's URL :D}x
T]  
private String sFilePath; //Saved File's Path j\f;zb?F  
private String sFileName; //Saved File's Name jY$Bns&.w  
private int nSplitter; //Count of Splited Downloading File 2!cP[Ck  
i;y<gm"  

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public SiteInfoBean() Vd4x!Vk  
{//nSplitter的缺省值为5 ;" '`P[  
//default value of nSplitter is 5 }:5r#Cd  
this("","","",5); &`Q0&8d5  
} }7+G'=XI/  
i>_V?OT#5  
+*a:\b"fx  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G#@o6r  
{ v)!Rir5  
sSiteURL= sURL; 'h%)@q)J)  
sFilePath = sPath; Uc!}D  
sFileName = sName; Hwklk9U
 
this.nSplitter = nSpiltter; [IF3,C  
'{QbjG%<P  
4Wk/^*?  
} #q9jFW8  
zPWG^  

>1T=Aw2Z.  
public String getSSiteURL() C]K@SN$   
{ 2TmQaDu%b  
return sSiteURL; {jcrTjmxe  
} ^, q\S  
L9Z:>i?  
-wvrc3F  
public void setSSiteURL(String value) LtJ$ZE^GB  
{ G?&0Z++  
sSiteURL = value; ,m{Zn"?kS  
} ]L^X}[SH  
l131^48U  
5Lo{\7%  
public String getSFilePath() )/HSt%>  
{ mNc(  
return sFilePath; :@KWp{ D7  
} `XB(d@%  
*eH[~4  
;<Oe\X  
public void setSFilePath(String value) {kD|8["Ie'  
{ R}8!~Ma`|  
sFilePath = value; `LVItP(GUM  
} &Zs h-|N  
{vx{H
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CSRcTxH  
public String getSFileName() z,87;4-  
{ =&U JFu  
return sFileName; NYM$0v`0YK  
} $fPf/yQmC  
vY7C!O/y_k  
k=Pu4:RF  
public void setSFileName(String value) 0V{-5-.  
{ V?kJYf(<  
sFileName = value; D*|h c  
} Mou>|U1e"  
|#^u%#'[2  
"KcSOjvJ  
public int getNSplitter() Z=|:D,&  
{ 8RVNRV@g%  
return nSplitter; 2shr&Mfp[  
} m@;X%wf<U  
UN'hnqC  
CtTG`)"|  
public void setNSplitter(int nCount) ?9mFI(r~  
{ 1t+]r:{  
nSplitter = nCount; oil s;*q  
} ~j^HDHY@  
} T|GRkxd,E3  
[(BA:x1  
Nj1vB;4Nx  
/* <8|vj2d2  
**Utility.java br.jj  
*/ { .B^  
package NetFox; f$Q#xlQM  
/d%&s^M:  
^DS9D:oE  
public class Utility { h$)!eSu  
6k%N\!_TUW  
F[ N{7C3  
public Utility() sI,T"D?  
{ \S[:  
, b ,`;I  
1`Cr1pH  
} Q!7Er  
l]%_D*<Y  
//线程睡眠 INby0S  
public static void sleep(int nSecond) w}zl=w{G  
{ KV k 36;$  
try{ ld-c?  
Thread.sleep(nSecond); 5u'"m<4  
} ^Jcs0c @\  
catch(Exception e) ,DqI> vx|  
{ n,hHh=.Fu  
e.printStackTrace (); {xi$'r  
} t/yGMR=  
} 1Cki}$k@  
]sE~gro  
//日志 (NyS2`  
public static void log(String sMsg) , ?WTX  
{ DPw"UY:  
System.err.println(sMsg); z\*ii<-@  
} EjV,&7o)  
'b]GcAL  
'*MNRduE6  
public static void log(int sMsg)  ]hpocr  
{ MLtfi{;LH  
System.err.println(sMsg); jY-{hW+r  
} HUuL3lYka  
} ?k<i e2  
tH,}_Bp  
v T2YX5k&,  
/* *.K+"WS%  
**TestMethod.java DlC`GZEtqh  
*/ 8fKt6T  
package NetFox; r@5_LD@f  
y-m<&{q  
6]^ShOX_Z  
public class TestMethod { L(XGD  
y2gI]A  
1`)ie%=  
public TestMethod() fWhwI+  
{ ///xx/weblogic60b2_win.exe xbnx*4o0  
try{ h-+9Bv]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C=2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  Iz*'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); f9W@!]LHJ  
fileFetch.start(); ?M.n 9|}y  
} fNPHc_?Ybj  
catch(Exception e){e.printStackTrace ();} kngkG|du  
}26?bd@e`  
\`
}Rdr!p%  
} k"Y9Kc0XoU  
7tP?([o%F  
9G_bM(q'^2  
public static void main(String[] args) 8VQJUwf;  
{ Gu}|CFL\  
new TestMethod(); /.9j$iK#  
}  ;)s$Et%  
} wkOo8@J\  
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