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http断点续传简单实现(java)

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/* fN0D\Mu!)b  
**SiteFileFetch.java ?B@hCd)  
*/ CrS[FM= +W  
package NetFox; aFIet55o  
import java.io.*; pRMM1&H  
import java.net.*; <u4GIi <sm  
ZJy D/9y  
SkvKzV.R;  
public class SiteFileFetch extends Thread { )I1LBvfQ  
uKpl+>  
qaw5<  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8y|(]5 'r  
long[] nStartPos; //开始位置 :JW~$4  
long[] nEndPos; //结束位置 i;/qJKr&#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?xN8 HG4  
long nFileLength; //文件长度 *aG0p&n}  
boolean bFirst = true; //是否第一次取文件 `q$DNOrS  
boolean bStop = false; //停止标志 f}Uw%S=w,  
File tmpFile; //文件下载的临时信息 -BEPpwb<g  
DataOutputStream output; //输出到文件的输出流 o<V-gS  
_QXo4z!a8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,wRrx&  
public SiteFileFetch(SiteInfoBean bean) throws IOException HK2`.'D  
{ \+cQiN b@  
siteInfoBean = bean; C$,S#n@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b#82G`6r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )h+JX8K)l  
if(tmpFile.exists ()) !Z4,UTu|Q  
{ ;uba  
bFirst = false; fC~WuG 3  
read_nPos(); >D-$M_  
} 1$xt=*.u|  
else N3x}YHFF  
{ <<UlFE9"  
nStartPos = new long[bean.getNSplitter()]; 5O*+5n  
nEndPos = new long[bean.getNSplitter()]; @B&hR} 4  
} K"g[%O<  
W@UHqHr:\  
aQRZyE}  
Y~Jq!  
} Ef?_d]  
` -w;=_Bm  
OW #pBeX99  
public void run() ](Sp0t  
{ kkzXv`+  
//获得文件长度 @|d|orMC  
//分割文件 \!w7 N :m  
//实例FileSplitterFetch iqOd]H]v  
//启动FileSplitterFetch线程 & JF^a  
//等待子线程返回 ):.]4n{L  
try{ y<;#*wB  
if(bFirst) /ox}l<ha  
{ ryPz?Aw(4  
nFileLength = getFileSize(); 7J 0!v q  
if(nFileLength == -1) Z/_RQ q   
{ >+$1 p_  
System.err.println("File Length is not known!"); hwC3['  
} qbT].,?!U  
else if(nFileLength == -2) VBd.5YW  
{ &}P62&  
System.err.println("File is not access!"); koAc-o  
} D.\p7 NJ  
else 3UH=wmG0w  
{ H"n"Q:Yp  
for(int i=0;i<nStartPos.length;i++) NB, iC [e  
{ sRYFu%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 85H8`YwPh  
} `qr[0wM  
for(int i=0;i<nEndPos.length-1;i++) `FmI?:Cv  
{ LiN{^g^fx  
nEndPos = nStartPos[i+1]; e`C'5`d]  
} KU$.m3A>  
nEndPos[nEndPos.length-1] = nFileLength; O(!wDnhc  
} }l_) d  
} IJ=~hBI  
G>H&M#7K  
2TIZltFS0e  
//启动子线程 O'j;"l~H|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lRentNg0b  
for(int i=0;i<nStartPos.length;i++) OcIJT1  
{ C>j"Ck^<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ip<STz]-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C' ny 2>uA  
nStartPos,nEndPos,i); 3+(Fq5I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;O.U-s  
fileSplitterFetch.start(); F lbL`@4M  
} uTn(fs) D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bz ]64/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?hmj0i;XC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S . 1~#  
nEndPos = " + nFileLength); 7gPkg63  
// fileSplitterFetch[nPos.length-1].start(); f<y""0L9  
LN_6>u  
UWmWouA  
//等待子线程结束 .dl1sv U  
//int count = 0; N?R1;|Z]  
//是否结束while循环 +EkZyM~z2  
boolean breakWhile = false; Cee?%NaTS  
2j( w*k q~  
0M:.Jhp  
while(!bStop) _DH,$evS%  
{ *I>1O*  
write_nPos(); t;ggc{  
Utility.sleep(500); ~6{;3"^<  
breakWhile = true; 2<|+h= &  
&]uhPx/  
|'1[\<MM3  
for(int i=0;i<nStartPos.length;i++) V#5BZU-  
{ !3d +"tL S  
if(!fileSplitterFetch.bDownOver) +&Sf$t 1  
{ J/ <[irC  
breakWhile = false; He&dVP  
break; e7 5*84  
} |67<h5Q1  
} 2h u;N  
if(breakWhile) piY=(y&3  
break; mp !6MOQ  
/GfC/)1_  
+9,"ne1'e  
//count++; 64`V+Hd  
//if(count>4) NDCZc_  
// siteStop(); xZbm,. v  
} Oh-HfJyi  
jjEkz 5  
%w_h8  
System.err.println("文件下载结束!"); [ @&  
} B9Y "J  
catch(Exception e){e.printStackTrace ();} LlX 7g _!  
} 7S1 Y)  
EC&w9:R  
o= N=W  
//获得文件长度 }-YD_Pm K-  
public long getFileSize() ="<+^$7:k  
{ EZE/~$`3   
int nFileLength = -1; )\'U$  
try{ KS3 /  
URL url = new URL(siteInfoBean.getSSiteURL()); fg+Q7'*Vq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h#'(UZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); fMI4'.Od  
,W7\AY07]  
ES }@mO  
int responseCode=httpConnection.getResponseCode(); x gnt)&7T  
if(responseCode>=400) doVBVTk^  
{ 1k3wBc 5<  
processErrorCode(responseCode); 69TQHJ[  
return -2; //-2 represent access is error mEr* n  
} \0'o*nlJ  
d,6 Z  
xSug-  
String sHeader; HE7JQP!q  
N1zB; -0t  
f-tjMa /_  
for(int i=1;;i++) 0:Yz'k5  
{ `lqMifD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fp|b@  
//Utility.log(in.readLine()); U}_l]gNn  
sHeader=httpConnection.getHeaderFieldKey(i); JrQ*.lJj  
if(sHeader!=null) w*uHB;?  
{ _<=U.T`  
if(sHeader.equals("Content-Length")) 8s6[?=nM  
{ >A7),6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w91{''sK  
break; t8E'd :pE  
} wJ/k\  
} (Lo<3a-]  
else J`Q#p%W  
break; 6Z\[{S];  
} ,3!l'|0jJ  
} ''s]6Jjw  
catch(IOException e){e.printStackTrace ();} oJvF)d@gU  
catch(Exception e){e.printStackTrace ();} %o.{h  
d_-{-@  
*ukE"Aj  
Utility.log(nFileLength); ~^UQw? ;  
6~ev5SD;f  
66,?f<b  
return nFileLength; g0 \c  
} C(Yk-7  
OAEJ?ik  
hS OAjS  
//保存下载信息(文件指针位置) 6(f[<V!r  
private void write_nPos() q UY;CEf  
{ W1w)SS  
try{ BVC{Zq6hi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0OMyE9jJJ  
output.writeInt(nStartPos.length); xUD$i?3z  
for(int i=0;i<nStartPos.length;i++) F*d{<  
{ `<>8tZS9"  
// output.writeLong(nPos); A{E0 a:v  
output.writeLong(fileSplitterFetch.nStartPos); Y4Z?`TL  
output.writeLong(fileSplitterFetch.nEndPos);  1Nk}W!v  
} (t9qwSS8z  
output.close(); Tj{!Fx^H  
} 'ej{B0rE  
catch(IOException e){e.printStackTrace ();} >~$ S!  
catch(Exception e){e.printStackTrace ();} .6 E7 R  
} AMYoSc  
A_%}kt (6  
t@/r1u|iq  
//读取保存的下载信息(文件指针位置) 5Wi5`8m  
private void read_nPos() ]~(Ipz2NP  
{ ZH%[wQ~4  
try{ =fHt|}.K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cuR|cUK  
int nCount = input.readInt(); &T}v1c7)  
nStartPos = new long[nCount]; U<r<$K  
nEndPos = new long[nCount]; &fj&UBA  
for(int i=0;i<nStartPos.length;i++) &K^h'>t'  
{ o\Hg2^YY>  
nStartPos = input.readLong(); _}!Q4K  
nEndPos = input.readLong(); j<+iL]b  
} .@APxeU  
input.close(); "MXd!  
} )}c$n  
catch(IOException e){e.printStackTrace ();} +X;6%O;  
catch(Exception e){e.printStackTrace ();} ]'_z (s}  
} L#u6_`XJ+  
RkLH}`#  
XR\ iQ  
private void processErrorCode(int nErrorCode) hBE}?J>  
{ <UQ:1W8>B  
System.err.println("Error Code : " + nErrorCode); (7ew&u\Li  
} eOn,`B1  
fD\h5`-  
 df 1* [  
//停止文件下载 u(ZS sftat  
public void siteStop() 1"odkM  
{ BJj~fNm1Zr  
bStop = true; 3 XfXMVm  
for(int i=0;i<nStartPos.length;i++) }C#YR( ]  
fileSplitterFetch.splitterStop(); 6w}:w?=6  
jd2Fh):q  
m2|0<P@k!  
} !gf&l ^)  
} 'KQu z)-  
//负责部分文件的抓取 g\(7z P  
**FileSplitterFetch.java VY _(0  
*/ hkU# lt  
package NetFox; Ky nZzR  
(I[o;0w  
t41cl  
import java.io.*; _i8$!b2Mr  
import java.net.*; ,(`@ZFp$  
RL&3 P@r  
%q*U[vv  
public class FileSplitterFetch extends Thread { nLtP^ 1~9H  
cR5<.$aY  
KH KqE6  
String sURL; //File URL &`TX4b^/!  
long nStartPos; //File Snippet Start Position =_yOX=g|  
long nEndPos; //File Snippet End Position N%B#f\N  
int nThreadID; //Thread's ID <O>Q;}>gfc  
boolean bDownOver = false; //Downing is over Zo0&<QWj  
boolean bStop = false; //Stop identical ,XA;S5FE  
FileAccessI fileAccessI = null; //File Access interface Pm?6]] 7  
,+X8?9v  
c~RIl5j  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >M1/m=a  
{ II<<-Y6  
this.sURL = sURL; fRa1m?%s  
this.nStartPos = nStart; p[uwG31IL`  
this.nEndPos = nEnd; E?XA/z !  
nThreadID = id; D9LwYftZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xj/ X.  
} g(5s{njL  
Oy|9po  
lHGv:TN  
public void run() Xj-3C[ 8@  
{ \:=Phbn  
while(nStartPos < nEndPos && !bStop) Sej$x)Q\t  
{ ;OKQP~^iH2  
,Xh4(Gn#b  
.M! (|KE4  
try{ i5n 'f6C  
URL url = new URL(sURL); QHM39Eu]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ./g0T{&  
httpConnection.setRequestProperty("User-Agent","NetFox"); kv5Qxj}  
String sProperty = "bytes="+nStartPos+"-"; S$H4xkKs  
httpConnection.setRequestProperty("RANGE",sProperty); Qp=uiXs  
Utility.log(sProperty); cn\_;TYiJ  
%eah=e  
lT:<ZQyjT  
InputStream input = httpConnection.getInputStream(); rzTyHK[  
//logResponseHead(httpConnection); 3?geJlD4  
7]v-2 *  
wM&G-~9ujk  
byte[] b = new byte[1024]; fzKKK+   
int nRead; YT:1=Nf}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ci*5E$+\  
{ x9ws@=[:  
nStartPos += fileAccessI.write(b,0,nRead); 0?:ZERv  
//if(nThreadID == 1) -Qgfo|po  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eQLa.0  
} ^4fkZh  
|-|BM'Y  
?eO|s5r  
Utility.log("Thread " + nThreadID + " is over!"); an7N<-?  
bDownOver = true; X%-4x   
//nPos = fileAccessI.write (b,0,nRead); ?SAi t Q3  
} 7RLh#D|  
catch(Exception e){e.printStackTrace ();} *= 71/&B  
} m,KY_1%M  
} hB.dqv]^  
Kq?7#,_  
B%pvk.`  
//打印回应的头信息 ) )F.|w  
public void logResponseHead(HttpURLConnection con) 1,QRfckks  
{ _SaK]7}m!  
for(int i=1;;i++) f/B--jq  
{ h>/ViB@"W|  
String header=con.getHeaderFieldKey(i); !+6l.`2WI  
if(header!=null) ,J^Op   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); eXd(R>Mx  
Utility.log(header+" : "+con.getHeaderField(header)); R3PhKdQ"  
else st2>e1vg  
break; Jc)1}  
} _e 3'f:  
} }B- A*TI<h  
U)!AH^{32  
W% [5~N  
public void splitterStop() ts]7 + 6V  
{ GN<I|mGLJK  
bStop = true; w}0Qy  
} JK(&E{80  
-AT@M1K7%  
hvyN8We  
} 6!nb)auVi  
D:(f"  
b{rmxtx  
/* ttnXEF  
**FileAccess.java 7|-xM>L$A  
*//文件访问(定位,写) D$cMPFa2Nt  
package NetFox; h 3&:"*A2  
import java.io.*; @nP}q!y  
Ic K=E ]p  
2YKM9Ks  
public class FileAccessI implements Serializable{ O[y`'z;C  
}dUC^04  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 uKy*N*}  
RandomAccessFile oSavedFile; O+?zn:  
long nPos; |S{P`)z%f  
[,^dM:E/  
s%oAsQ_y  
public FileAccessI() throws IOException {1aAm+  
{ !yX<v%>_0  
this("",0); ~8(X@~Tn*  
} ^-u HdafP  
#sU~fq  
Wp}9%Mq~Jy  
public FileAccessI(String sName,long nPos) throws IOException ]$*{<  
{ aT#{t {gkA  
oSavedFile = new RandomAccessFile(sName,"rw"); eC?/l*gF 3  
this.nPos = nPos; *\KMkx  
oSavedFile.seek(nPos); nn L$m_K~  
} uV_)JZ W,L  
q7&yb.<KD.  
7;'.5,-3c  
public synchronized int write(byte[] b,int nStart,int nLen) 9K46>_TyH  
{ =t$mbI   
int n = -1; i?>> 9f@F  
try{ Kxc$wN<  
oSavedFile.write(b,nStart,nLen); 2ZbY|8X$r  
n = nLen; o:8S$F`O@  
} R}wwC[{  
catch(IOException e) ckN(`W,xp  
{ #IaBl?}r^  
e.printStackTrace (); o+-Ge J  
} C.eV|rc@T  
l~4e2xoT  
QP5:M!O<)  
return n; l8xd73D)8  
} wYQ1Z  
i %hn  
+%}5{lu_e  
} ]2\2/~l  
qa$[L@h>  
EkStb#  
/* M-Z6TL  
**SiteInfoBean.java GQ-e$D@SfB  
*/ t6bWSz0  
package NetFox; Gj7QG IKx  
hw ;dm  
e,#+Xx0M  
public class SiteInfoBean { [wy3Ld  
|T$a+lHMD  
O5TK&j  
private String sSiteURL; //Site's URL fb0T/JT w  
private String sFilePath; //Saved File's Path Eo { 1y  
private String sFileName; //Saved File's Name GrLM${G  
private int nSplitter; //Count of Splited Downloading File &FJU%tFA  
@8M'<tr<z  
yToT7 X7F7  
public SiteInfoBean() D)*_{   
{//nSplitter的缺省值为5 a(x.{}uG,  
//default value of nSplitter is 5 yA !3XUi  
this("","","",5); 5gc:Y`7t  
} dWW-tHv#  
^b"x|8  
e<L 9k}c  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kKxL04  
{ c+E//X|  
sSiteURL= sURL; } Jdh^t.  
sFilePath = sPath; r>@ B+Xi  
sFileName = sName; de=5=>P7  
this.nSplitter = nSpiltter; w>z8c3Dq}  
x;ERRK  
$vgmoJ@X0  
} =0 C l  
, `[Z`SUk`  
Qe @A5#  
public String getSSiteURL() =e-a&Ep-z  
{ Ersr\ZB  
return sSiteURL; (s V]UGrZ  
} j#LV7@H.e?  
D y`W5_xSz  
B7Ki @)  
public void setSSiteURL(String value) ]|C_`,ux  
{ 1*!c X  
sSiteURL = value; 0,1L e$)6  
} @wYQLZ  
P EX26==  
_q$0lqq~u  
public String getSFilePath() %2@ Tj}xa  
{ |z!q r}i  
return sFilePath; Q QsVIHA  
} {UX"Epd);n  
5bF9I H  
]689Q%D  
public void setSFilePath(String value) H7z>S G0  
{ AQnJxIL:  
sFilePath = value; z&C{8aQ'  
} -(/2_&"  
a2c x  
c]s (u+i  
public String getSFileName() c ,h.`~{  
{ O:`GL1{ve?  
return sFileName; RQj`9F  
} xVsa,EX b  
LT,iS)dY+  
*/%$6s~  
public void setSFileName(String value) ~4MtDf  
{ g( ]b\rj  
sFileName = value; 8Z9MD<RLw  
} ~h>rskJ _  
"fX_gN?  
hV3,^#9o  
public int getNSplitter() [Vrc:%Jk  
{ ;-3h~k  
return nSplitter; '|YtNhWZ?  
} V9+xL 1U#  
`YFkY^T  
p/ziFpU  
public void setNSplitter(int nCount) Z-4K?;g'k  
{ U7nsMD  
nSplitter = nCount; iN:G/ss4O  
} a^RZsR  
} ^#a#<8Jz  
K?h[.`}  
|Q5H9<*  
/* c0!Te'?  
**Utility.java $Qn& jI38  
*/ S2koXg(  
package NetFox; C $]5l; `  
bh=\  
KcIc'G 9  
public class Utility { "_ nX5J9  
)x$!K[=  
IT8B~I\OY  
public Utility() JiKImz  
{ ?~F]@2)5w  
hVlyEsLg  
,DE(5iDS  
} !&@2  
NJ >I%u*  
//线程睡眠 y\[L?Rmd  
public static void sleep(int nSecond) fdd~e52f  
{ re7!p(W?,  
try{ =L:[cIRrT;  
Thread.sleep(nSecond); bZxv/\  
} cNdu.c[@  
catch(Exception e) x2sN\tOh^  
{ r`?&m3IOP  
e.printStackTrace (); fy9uLl}h  
} ILNE 4n  
} 91BY]N  
V78Mq:7d  
//日志 K3La9O)>  
public static void log(String sMsg) G"}qV%"6"  
{ )URwIe{  
System.err.println(sMsg); Sq?,C&LsA  
} g* %bzfk=|  
}%_qx|(P|t  
HTxB=Q|  
public static void log(int sMsg) O:2 #_  
{ Tsu\oJ[  
System.err.println(sMsg); b21}49bHN  
} k"t >He  
} C,[ L/!  
P~&O4['<  
TLy ;4R2Nn  
/* &q.)2o#Q.  
**TestMethod.java mG X\wta  
*/ P<8LAc$T  
package NetFox; yxqTm%?y  
wyp{KIV  
STv(kQs  
public class TestMethod { \{kHSV%z  
EH(tUwY%{  
FSv1X  
public TestMethod() %cS#+aK6M'  
{ ///xx/weblogic60b2_win.exe aWdUuid  
try{ nZe\5`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AmZuo_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MdLj,1_T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R j-jAH  
fileFetch.start(); m^ z,,t9  
}  /; +oz  
catch(Exception e){e.printStackTrace ();} `Rrr>vj  
0"hiCGm'  
Ec+22X  
} ?.8<-  
q5!0\o:  
/\~l1.6`  
public static void main(String[] args) R;%^j=Q  
{ NOV.Bs{ yL  
new TestMethod(); 8:~b &>   
} miPmpu!  
} 8`a,D5U:  
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