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http断点续传简单实现(java)

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/* 9kojLqCT  
**SiteFileFetch.java _|]x2xb)  
*/ 8f7>?BUS,  
package NetFox; | 3%8&@ho  
import java.io.*; 7|D+Ihy;  
import java.net.*; {[(h[MW#  
OTp]Xe/  
fV:83|eQ  
public class SiteFileFetch extends Thread { .o8t+X'G  
Y~Ifj,\  
IAEAhqp  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4=.so~9odX  
long[] nStartPos; //开始位置 ^&)|sP  
long[] nEndPos; //结束位置 b2]Kx&!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jIF |P-  
long nFileLength; //文件长度 Bf:Q2slqI  
boolean bFirst = true; //是否第一次取文件 {U1m.30n  
boolean bStop = false; //停止标志 XM}hUJJW  
File tmpFile; //文件下载的临时信息 l]cFqL p  
DataOutputStream output; //输出到文件的输出流 to\N i~a&  
TKjFp%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  9a kH  
public SiteFileFetch(SiteInfoBean bean) throws IOException |M_UQQAB|  
{ !wp3!bLp  
siteInfoBean = bean; <1 pEwI~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }i2V.tVB-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E e]-qN*8  
if(tmpFile.exists ()) B;WCTMy}  
{ KU;9}!#  
bFirst = false; d1kJRJ   
read_nPos(); iCyf Oh  
} 0g\(+Qg^  
else [r-p]"R  
{ SB7c.H,  
nStartPos = new long[bean.getNSplitter()]; >Se,;cB'/]  
nEndPos = new long[bean.getNSplitter()]; [:V$y1  
} %UM *79  
_~pbqa,  
5PW^j\G-f  
2-b6gc7  
} =mGez )T5\  
MW{8VH6+  
vFsLY  
public void run() o14cwb  
{ 4OX^(  
//获得文件长度 o Rzi>rr  
//分割文件 c|1&lYal;  
//实例FileSplitterFetch Ev P{p  
//启动FileSplitterFetch线程 i?~3*#IpD  
//等待子线程返回 pNIf=lA  
try{ y?:.;%!E  
if(bFirst) TPY}C  
{ rbpSg7}Q  
nFileLength = getFileSize(); ty`DJO=Omj  
if(nFileLength == -1) CP{cAzHO  
{ @I*{f  
System.err.println("File Length is not known!");  bF(f*u  
} 03(4 x'z  
else if(nFileLength == -2) o]:9')5^  
{ 4&f3%eTi  
System.err.println("File is not access!"); 0RK!/:'  
} LK"69Qx?5q  
else |I|fMF2K  
{ R$Q.sE  
for(int i=0;i<nStartPos.length;i++)  *,m;  
{ ? qA]w9x  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F>cv<l =6l  
} @K]|K]cby  
for(int i=0;i<nEndPos.length-1;i++) *:NQ&y*uj  
{ 8*fv'  
nEndPos = nStartPos[i+1]; HKr Mim-  
} )WoxMmz  
nEndPos[nEndPos.length-1] = nFileLength; .6V}3q$-@  
} ^I)N. 5  
} e$pV%5=  
hzRYec(  
g[t [/TV   
//启动子线程 * H9 8Du  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V_:&S2j  
for(int i=0;i<nStartPos.length;i++) :hV7> rr  
{ )0R'(#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )Beiu*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?rup/4|  
nStartPos,nEndPos,i); m9A!D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Bw{I;rW{2  
fileSplitterFetch.start(); ukY"+&  
} Bnd [X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [sb[Z:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M xG W(p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e!r-+.i(  
nEndPos = " + nFileLength); AvHCO8h|  
// fileSplitterFetch[nPos.length-1].start(); @gtQQxf"  
^BL"wk  
2>H24F  
//等待子线程结束 FEVlZ<PW3I  
//int count = 0; Wr5V`sM  
//是否结束while循环  {>%&(  
boolean breakWhile = false; z"4~P3>{g  
BX^tR1  
(3&?wy_l  
while(!bStop) -)/$M(Pu"  
{ h65-s  
write_nPos(); -Vhw^T1iV  
Utility.sleep(500); uOGw9O-d9  
breakWhile = true; ilva,WFa^  
-o.:P>/  
W"3ph6[eW  
for(int i=0;i<nStartPos.length;i++) )];K .zP  
{ 5P$4 =z91  
if(!fileSplitterFetch.bDownOver) 0P(!j_2m  
{ 1>&]R=  
breakWhile = false; I)W`sBL  
break;  ^Va1f'g  
} Lu0x (/  
} R^e.s -  
if(breakWhile) s|B3~Q]  
break; t!\tF[9e  
XF_pN[}  
C{XmVc.  
//count++; f>Jr|#k  
//if(count>4) K!]/(V(}  
// siteStop(); *r% c  
} 9RI-Lq`  
m<g~H4  
{$Gd2g O  
System.err.println("文件下载结束!"); c:u5\&~{  
} uL/m u<  
catch(Exception e){e.printStackTrace ();} Ji 0 tQV  
} FjI`uP  
,<p}o\6  
U!Z,xx[]  
//获得文件长度 K:Q<CQ2  
public long getFileSize() iRi-cQVy  
{ %-e 82J1  
int nFileLength = -1; s&!a  
try{ '-/xyAzS  
URL url = new URL(siteInfoBean.getSSiteURL()); k,F6Tx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xpx\=iAe  
httpConnection.setRequestProperty("User-Agent","NetFox"); \K<QmK  
a+T.^koY  
K>l~SDcZ3  
int responseCode=httpConnection.getResponseCode(); qXjxNrK  
if(responseCode>=400) Nm>A'bLM  
{ LAe6`foW/  
processErrorCode(responseCode); 4vV:EF-  
return -2; //-2 represent access is error v2;`f+  
} ,T8~L#M~  
!GEJIefx_  
e,XYVWY%  
String sHeader; ; p{[1  
_W'-+,  
\A6B,|@  
for(int i=1;;i++) fLm*1S|%\  
{ |WdPE@P  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \`\ZTZni  
//Utility.log(in.readLine()); B i<Q=x'Z;  
sHeader=httpConnection.getHeaderFieldKey(i); DXK}-4"\  
if(sHeader!=null) JOim3(5?s  
{ Z@@K[$  
if(sHeader.equals("Content-Length")) fn 6J *[`  
{ f[^Aw(o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 84pFc;<  
break; =+MPFhvg!  
} -n<pPau2  
} Y~E`9  
else ; XN{x  
break; :7?FF'u  
} X=8{$:  
} M b1s F  
catch(IOException e){e.printStackTrace ();} j;iAD:nf  
catch(Exception e){e.printStackTrace ();} ;Nj7qt  
 !V g`  
4J([6<  
Utility.log(nFileLength); pDCeQ6?  
 3 +fp2  
\1 &,|\E#  
return nFileLength; l9u!aD  
} FA3~|Zg  
EJ:%}HhA  
nl,uuc*;  
//保存下载信息(文件指针位置) EeRX+BM,  
private void write_nPos() c[1oww  
{ V0XvJ  
try{ 6}Y#=}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O ,h;hQZ  
output.writeInt(nStartPos.length); :| 8M`18lZ  
for(int i=0;i<nStartPos.length;i++) {"QNJq#:  
{ zY!j:FT1HY  
// output.writeLong(nPos); FfPar:PHj  
output.writeLong(fileSplitterFetch.nStartPos); k<{{*  
output.writeLong(fileSplitterFetch.nEndPos); spPNr  
} oVfLnI ;  
output.close(); &,CiM0  
} P8)=Kbd  
catch(IOException e){e.printStackTrace ();} ,.1Psz^U  
catch(Exception e){e.printStackTrace ();} Y@ksQ_u  
} qd)/9*|Jl  
Fv<F}h?6  
.KUv( -  
//读取保存的下载信息(文件指针位置) Z%/=|[9i  
private void read_nPos() }YNR"X9*)/  
{ NI [ pp`  
try{ C-MjJ6D<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zvH8^1yzG  
int nCount = input.readInt(); 2=`o_<P'"  
nStartPos = new long[nCount]; l6 H|PR{  
nEndPos = new long[nCount]; \(Y\|zC'0$  
for(int i=0;i<nStartPos.length;i++) e`xdSi>E  
{ mFaZio0GK  
nStartPos = input.readLong(); D(RTVef  
nEndPos = input.readLong(); c%G{#}^2  
} /M4{Wc  
input.close(); c>Xs&_  
} QY?~ZwYB  
catch(IOException e){e.printStackTrace ();} gPsi  
catch(Exception e){e.printStackTrace ();} (l- ab2'  
} YccH+[X;  
H'HA+q  
j<@lX^  
private void processErrorCode(int nErrorCode) s`'{I8'p/  
{ )PuFuf(wz  
System.err.println("Error Code : " + nErrorCode); ?>rW>U6:P  
} sN2p76KN  
 &NK,VB;  
j4`0hnqI  
//停止文件下载 v`zJb00DT  
public void siteStop() gSUcx9f]  
{ MET' (m  
bStop = true; $79=lEn,  
for(int i=0;i<nStartPos.length;i++) "4+ WZR]  
fileSplitterFetch.splitterStop(); 0rDh}<upjk  
i/ )am9  
giIWGa.a+  
} ]d0tE?9  
} \$e)*9)  
//负责部分文件的抓取 Xudg2t)+K  
**FileSplitterFetch.java _p&]|~a  
*/ [@b&? b~K  
package NetFox; iIa'2+  
pDIVZC  
u TK,&  
import java.io.*; uPG4V2  
import java.net.*; 2fR02={-  
Md2>3-  
khrb-IY@  
public class FileSplitterFetch extends Thread { DB:+E|vSD  
/.MN  
;1.,Sn+zO  
String sURL; //File URL _Khc3Jo  
long nStartPos; //File Snippet Start Position 87P>IO  
long nEndPos; //File Snippet End Position +hT:2TXn  
int nThreadID; //Thread's ID )oPLl|=h  
boolean bDownOver = false; //Downing is over /bi[ e9R  
boolean bStop = false; //Stop identical \LppYXz  
FileAccessI fileAccessI = null; //File Access interface Q/_f zg  
`-l6S  
DhT>']Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v` 7RCg`  
{ ]0)|7TV*  
this.sURL = sURL; O 8u j`G 9  
this.nStartPos = nStart; -}=%/|\FG  
this.nEndPos = nEnd; ,:H\E|XeBw  
nThreadID = id; FUOI3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b6F4>@gjg  
} )3w@]5j  
&[/w_| b  
)Es"LP]  
public void run() muZ~*kMc  
{ DRgTe&+  
while(nStartPos < nEndPos && !bStop) ul2")HL];  
{ CS-uNG6  
ayD}r#7  
pxf$ 1  
try{ k |%B?\m  
URL url = new URL(sURL); }J1tdko#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F\k+[`%{  
httpConnection.setRequestProperty("User-Agent","NetFox"); hn=[1<#^(  
String sProperty = "bytes="+nStartPos+"-"; YmgLzGk`  
httpConnection.setRequestProperty("RANGE",sProperty); ?5 cI'  
Utility.log(sProperty); &n?^$LTPY  
0[*qY@m:Z  
q+]h=:5=I  
InputStream input = httpConnection.getInputStream(); ^(h+URFpA  
//logResponseHead(httpConnection); TGe;HZ  
T{Uc:Z  
c|62jY"$-2  
byte[] b = new byte[1024]; *2Ht &  
int nRead; dJ""XaHqf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [P7N{l=I  
{ &2zq%((r  
nStartPos += fileAccessI.write(b,0,nRead); 0B@Jity#!  
//if(nThreadID == 1) Qj6/[mUr~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R>"OXFaE  
} y+6o{`0  
pg%aI,  
)>-ibf`#?  
Utility.log("Thread " + nThreadID + " is over!"); Zx  bq  
bDownOver = true; glXZZ=j  
//nPos = fileAccessI.write (b,0,nRead); iN0nw]_*  
} Yvjc1  
catch(Exception e){e.printStackTrace ();} -'BA{#e}L  
} $.v5~UGb{\  
} $K'|0   
UHxE)]J  
MR<;i2p  
//打印回应的头信息 C[Dav&=^F  
public void logResponseHead(HttpURLConnection con) aj,T)oDbt6  
{ I=9!Rs(QF  
for(int i=1;;i++) z` FCs,?K  
{ B0WJ/)rK<  
String header=con.getHeaderFieldKey(i); ez!C?  
if(header!=null) mAW, ?h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ' n$ %Ls}S  
Utility.log(header+" : "+con.getHeaderField(header)); ql?=(b;D  
else e=;AfK  
break; % v7[[U{T  
} Zg`Mz _?  
} S"k *6 U  
OP|8Sk6 r  
e-*.Ca  
public void splitterStop() (B-43!C  
{ `8>Py~  
bStop = true; 9*=W-v  
} |{ PI102  
['*8IWg  
X'% ;B  
} QZhj b  
g HbxgeL  
njnDW~Snb  
/* -7&Gi +]  
**FileAccess.java D<X.\})Md  
*//文件访问(定位,写) R% ,<\d7  
package NetFox; ZwerDkd  
import java.io.*; NDAw{[.%  
#\ n8M  
M7+h(\H]2  
public class FileAccessI implements Serializable{ &o97u4xi  
,qrQ"r9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GS Q/NYK  
RandomAccessFile oSavedFile; 7ei|XfR  
long nPos; 3^ ~KB'RZ  
V{&rQ@{W  
`TPOCxM Mo  
public FileAccessI() throws IOException m7GR[MR  
{ u=/CRjot  
this("",0); pOkLb #  
} JiU9CeD3  
dG71*)<)t  
}sFm9j7yR  
public FileAccessI(String sName,long nPos) throws IOException P?]aWJ  
{ {]]|5 \F  
oSavedFile = new RandomAccessFile(sName,"rw"); :C8$Xi_i}  
this.nPos = nPos; LtKI3ou  
oSavedFile.seek(nPos); FSb Hn{@  
} )Cw`"n  
;kJA'|GX  
g@Qgxsyk>  
public synchronized int write(byte[] b,int nStart,int nLen) b (I2m  
{ PeE/iZ.  
int n = -1; 2kUxD8BcN  
try{ F5qFYL;  
oSavedFile.write(b,nStart,nLen); AkT<2H|4  
n = nLen; A &9(mB  
} okFvn;  
catch(IOException e) T'aec]u  
{ l?)ZJ3]a  
e.printStackTrace (); H7k PM[  
} A?T<",bO  
FsGlJ   
9A7@ 5F  
return n; !!nuAQ"E[  
} h<\_XJJ  
H<G4O02i_  
3o|I[!2.  
} ,mL !(US  
k%op> &  
v^7LctcVm  
/* !;!~n`  
**SiteInfoBean.java b2b75}_A  
*/ + EM_TTf4  
package NetFox; Y05P'Q  
}/,CbKi,+  
on7I l  
public class SiteInfoBean { oq_6L\ ~  
EIf ~dOgH  
Q!FLR>8  
private String sSiteURL; //Site's URL #s%-INcR  
private String sFilePath; //Saved File's Path ?<yM7O,4  
private String sFileName; //Saved File's Name WmQ 01v  
private int nSplitter; //Count of Splited Downloading File )*d W=r/$V  
9r2IuS0  
$.489x+'Z  
public SiteInfoBean() xT)psM'CL  
{//nSplitter的缺省值为5 <p?&udqD  
//default value of nSplitter is 5  X}6#II  
this("","","",5); *$M'`vj:  
} V8~jf-\$b  
U#o'H @  
6R29$D|HFO  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *AIEl"29  
{ 9=/N|m8.  
sSiteURL= sURL; Bz`yfl2  
sFilePath = sPath; )P>u9=?,=E  
sFileName = sName; /+3a n9h  
this.nSplitter = nSpiltter; N6[i{;K@N{  
Gj /3kS~@  
jUqy8q&  
} 6dEyv99  
PZD>U)M  
rB%$;<`/  
public String getSSiteURL() #9LzY  
{ ksjUr1o  
return sSiteURL; jAsO8  
} \ U-vI:J_  
il:nXpM!  
@oG)LT  
public void setSSiteURL(String value) ~H}en6Rc  
{ qUF1XJZ }z  
sSiteURL = value; 0X(]7b&~R  
} J:F^ #gW  
BXUF^Hj%  
efuK  
public String getSFilePath() kDz>r#%  
{ wn11\j&  
return sFilePath; 2PSTGG8JV  
} n|4;Hn1V  
hD<f3_k  
XL}<1- }  
public void setSFilePath(String value) L6i|:D32p  
{ %E27.$E_  
sFilePath = value; ".~{:=  
} uC]Z8&+obb  
7=*VpX1  
[Id}4[={e  
public String getSFileName() IGAzE(  
{ 4o9$bv  
return sFileName; I 2HT2c$  
} qU[O1bN  
}o9Aa0$*$  
]9S`[c$  
public void setSFileName(String value) S C_|A9  
{ RwTzz] M  
sFileName = value; X^@[G8v%  
} BZ F,=v  
}1%r%TikY  
|[cdri^?D  
public int getNSplitter() I&1!v8  
{ C/v}^#cLD  
return nSplitter; |&hU=J o  
} 0D)`2W  
Z]-WFU_ N  
s!6=|SS7  
public void setNSplitter(int nCount) p#_[  
{ `!w^0kZ  
nSplitter = nCount; 8t .dPy<  
} N)43};e  
} =V^@%YIn  
i|\{\d  
a]VGUW-  
/* $<ddy/4  
**Utility.java GF--riyfB  
*/ iY.eJlfH  
package NetFox; KC&`x |  
+|C[-W7Sw  
:J(sXKr[C  
public class Utility { @PcCiGZ  
nJVp.*S  
{(vOt'  
public Utility() ,{j4  
{ +*t|yKO>[  
TV{)n'aA  
t^@T`2jL  
} c#q"\"  
6d{j0?mM  
//线程睡眠 ?TuI:dC  
public static void sleep(int nSecond) "]]q} O?  
{ d]M[C[TOX  
try{ 2X @G"  
Thread.sleep(nSecond); } 21j  
} .u< U:*  
catch(Exception e) K ~>jApZ%  
{ ~5t?C<wo  
e.printStackTrace (); xtJAMo>g  
} _IYY08&(r  
} t>U!Zal"  
gEKO128  
//日志 X7e/:._SAH  
public static void log(String sMsg) sA_X<>vAKJ  
{ /Antb6E  
System.err.println(sMsg); .k]#XoE  
} z/vDgH!s  
org*z!;.   
r69WD .  
public static void log(int sMsg) cTj~lO6  
{ V<$*Y>;  
System.err.println(sMsg); POBpJg  
} _ +KmNfR  
} RWahsJTu  
B/Ba5z"r$  
#S i|!  
/* 3Hm7 uBZ  
**TestMethod.java caD5Pod4  
*/ ,35Ag#va  
package NetFox; deM~[1e[  
~N[|bPRmhE  
3zb)"\(R  
public class TestMethod { ma7fDo0,`h  
<R~KM=rL  
Cj$H[K}>  
public TestMethod() d[U1.SNL  
{ ///xx/weblogic60b2_win.exe 5<r)+?!n  
try{ a paIJ+^[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WOH9%xv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {U P_i2`.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oYq E*mA  
fileFetch.start(); \G=bj;&eF  
} ' PL_~  
catch(Exception e){e.printStackTrace ();} s?<!&Y  
3*\8p6G  
i;HH ! TaN  
} V~c(]K)-  
Isp_U5M  
u-M] A z-  
public static void main(String[] args) Fc{((x s  
{ h*l4Y!7  
new TestMethod(); TA9dkYlE/  
} T`mEO\f  
} Dtt\~m;AR  
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