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http断点续传简单实现(java)

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/* q,:\i+>K*  
**SiteFileFetch.java 1M 3U)U  
*/ SF.,sCk  
package NetFox; a S<JsB  
import java.io.*; _^a.kF  
import java.net.*; m@zxjIwT  
^S<Z'S  
8kMMQES  
public class SiteFileFetch extends Thread { kJDMIh|g  
tAc;O[L  
(5yg\3Jvp  
SiteInfoBean siteInfoBean = null; //文件信息Bean XLmbpEh  
long[] nStartPos; //开始位置 Opjt? ]  
long[] nEndPos; //结束位置 $ng\qJ"HF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PI{sO |  
long nFileLength; //文件长度 }1 _gemlf  
boolean bFirst = true; //是否第一次取文件 Wb4sfP_  
boolean bStop = false; //停止标志 d9Q%GG0]  
File tmpFile; //文件下载的临时信息 3[V|C=u0  
DataOutputStream output; //输出到文件的输出流 3Ji,n;QLm  
*f4KmiQ~ %  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) M/1Q/;0P  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4&y_+  
{ L\-T[w),z7  
siteInfoBean = bean; q>Q|:g&:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); siD Sm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &0>{mq}p,:  
if(tmpFile.exists ()) @Rx/]wyH  
{ K/%aoTO}  
bFirst = false; QGshc  
read_nPos(); Upv2s:wa}z  
} C62<pLJf  
else .Zwn{SMtu  
{ Np/[MC  
nStartPos = new long[bean.getNSplitter()]; iOJgZuP  
nEndPos = new long[bean.getNSplitter()]; }VFSF/\^  
} c89RuI `B~  
Hy `r}+  
@EZXPU  
g` h>:5]  
} MI@ RdXkY  
zM@iG]?kc  
o_5|L9  
public void run() 0 \h2&  
{ Ft>ixn  
//获得文件长度 R#T6I i  
//分割文件 P{}Oe *9"  
//实例FileSplitterFetch 5:s]z#8)  
//启动FileSplitterFetch线程 0c3G_I=  
//等待子线程返回 lZ.,"F@  
try{ Q`//HOM,  
if(bFirst) KX9ZwsC0  
{ /4T%&#6s  
nFileLength = getFileSize(); Wc]Fg9E  
if(nFileLength == -1) ,]cd%w9  
{ D:F!;n9  
System.err.println("File Length is not known!"); AVcZ.+?  
} SU#|&_wtr!  
else if(nFileLength == -2) { j/w3  
{ KK] >0QAY  
System.err.println("File is not access!"); d9^=#ot  
} pixI&iQ  
else ' l!QGKz  
{ lhjPS!A~  
for(int i=0;i<nStartPos.length;i++) Yb6\+}th  
{ &1?Q]ZRp  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qh&K{r*T  
} 6Edqg   
for(int i=0;i<nEndPos.length-1;i++) QU#/(N(U#T  
{ '8Gw{&&  
nEndPos = nStartPos[i+1]; R -h7c!ko  
} Tl1?5  
nEndPos[nEndPos.length-1] = nFileLength; ~]yqJYiid^  
} my} P\r.  
} L`Ic0}|lzy  
Z7f~|}  
G6J3F  
//启动子线程 ILVbbC`D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X:e'@]Z)?  
for(int i=0;i<nStartPos.length;i++) N&GcWcq  
{ 3{c&%F~!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *FAg^G&1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N&ddO-r[s  
nStartPos,nEndPos,i); WI6er;D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K{iay g!k  
fileSplitterFetch.start(); *1%g=vb  
} {Ise (>V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \ agC Q&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?3|ZS8y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eU12*(  
nEndPos = " + nFileLength); )l"0:1Ig  
// fileSplitterFetch[nPos.length-1].start(); S4(IYnwN  
S_QDYnF)`  
+amvQ];?Q8  
//等待子线程结束  z7K?rgH  
//int count = 0; O@$hG8:  
//是否结束while循环 3gM{lS}h#  
boolean breakWhile = false;  qJK^i.e  
2cDC6rul  
Wu}Co  
while(!bStop) ._R82 gy  
{ "d#s|_n,d)  
write_nPos(); #zQkQvAT9  
Utility.sleep(500); rvG qUmSUs  
breakWhile = true; cK258mY  
NMDNls&)k  
O]Hg4">f  
for(int i=0;i<nStartPos.length;i++) ?y '.sQ  
{ vbFAS:Y:+  
if(!fileSplitterFetch.bDownOver) ~ 52  
{ dqe_&C@*O  
breakWhile = false; ^g0 Ig2'  
break; E`s_Dr}K  
} pQ/:*cd+M  
} L fi]s  
if(breakWhile) }E=kfMu  
break; tyDtwV|  
)CmuC@ Q"  
m0edkt-x  
//count++; OYzJE@r^  
//if(count>4) ZN)/doK  
// siteStop(); SB;Wa%  
} >}I}9y+  
}+B7C2_\  
f&`*x t/  
System.err.println("文件下载结束!"); \?g%>D:O;  
} (r|T&'yK  
catch(Exception e){e.printStackTrace ();} 7q?Yd AUz  
} < d]|5  
kal8k-$#  
s=$7lYX  
//获得文件长度 nqH^%/7)A@  
public long getFileSize() dOhV`8l  
{ -`RJ k(  
int nFileLength = -1; 0{ ,zE  
try{ s%:fB(  
URL url = new URL(siteInfoBean.getSSiteURL()); y >OZ<!`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GWW@8GNI  
httpConnection.setRequestProperty("User-Agent","NetFox"); zZxP= c  
T'V(%\w  
V ": BAn  
int responseCode=httpConnection.getResponseCode(); J!H5{7.efN  
if(responseCode>=400) w(yU\ N  
{ 08f~vw"  
processErrorCode(responseCode); -3V~YhG  
return -2; //-2 represent access is error i`Yf|^;@2>  
} b'OO~>86  
!69^ kIi$  
1D`RR/g&  
String sHeader; {7wvC)WW  
ky#6M? \  
e\dT~)c  
for(int i=1;;i++) sV6A& Aw  
{ w0IB8GdF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y(R*Z^c}d,  
//Utility.log(in.readLine()); !G,$:t1-=V  
sHeader=httpConnection.getHeaderFieldKey(i); ^Pf&C0xXv  
if(sHeader!=null) gv,T<A?Z2  
{ yI%> w4Z  
if(sHeader.equals("Content-Length")) w?*KO?K  
{ WU4i-@Bm8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w(U/(C7R  
break; YfalsQ8  
} ? 1{S_  
} jysV%q 3  
else ^ZlV1G;/W@  
break; Rf^cw}jU  
} ""+*Gn 7^8  
} U,M,E@  
catch(IOException e){e.printStackTrace ();} NQJqS?^W&M  
catch(Exception e){e.printStackTrace ();} :6/OU9f/R  
#R8l"]fxr?  
L1xD$wl  
Utility.log(nFileLength); iK]g3ew|  
^zJ. W  
OW}A48X[+  
return nFileLength; StL[\9~:  
} gB(W`:[  
9O Q4\  
Ib\G{$r  
//保存下载信息(文件指针位置) kn"x[{d  
private void write_nPos() jq]"6/xxb  
{ GN9_ZlC  
try{ 9/M!S[N9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?>8zU;Aj  
output.writeInt(nStartPos.length); #[W[ |m  
for(int i=0;i<nStartPos.length;i++) UT~2}B9fc  
{ E, fp=.  
// output.writeLong(nPos); @qDrTH]5  
output.writeLong(fileSplitterFetch.nStartPos); @,&m`qzd+  
output.writeLong(fileSplitterFetch.nEndPos); @>@Nu g2   
} QL2y,?Mz7  
output.close(); B|=maz:_  
} aTm.10{^  
catch(IOException e){e.printStackTrace ();} weV#%6=5\  
catch(Exception e){e.printStackTrace ();} pCUOeQL(  
} zrO|L|F&P  
ss{=::#  
uq%3;#[0  
//读取保存的下载信息(文件指针位置) I0vn d7  
private void read_nPos() J\+gd%  
{ /&:9VMMj  
try{ .K1E1Z_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BDRVT Y(s  
int nCount = input.readInt(); Vk_&W.~  
nStartPos = new long[nCount]; t)Q @sKT6  
nEndPos = new long[nCount]; Y^Q|l%Qrb  
for(int i=0;i<nStartPos.length;i++) ?1:/ 6  
{ SQU%N  
nStartPos = input.readLong(); ]~Vu-@ /}  
nEndPos = input.readLong(); #ljg2:I+  
} 9:i,WJO  
input.close(); *.c9$`s  
} (I ds<n"  
catch(IOException e){e.printStackTrace ();} K=?F3tX^  
catch(Exception e){e.printStackTrace ();} ]C6[`WF  
} idS RWa  
QeJ.o.m{  
%OW9cqL>l  
private void processErrorCode(int nErrorCode) fsc~$^.~\  
{ DIp:S&q2  
System.err.println("Error Code : " + nErrorCode); "ue$DyN  
} #Rx"L&3Ue  
<lmJa#  
So *Wk "  
//停止文件下载 @1&;R  
public void siteStop() Fg\| e%  
{ \ e8*vos  
bStop = true; s]vJUC,s  
for(int i=0;i<nStartPos.length;i++) Sje0:;;|  
fileSplitterFetch.splitterStop(); HL}~W}!j  
% rY8  
>^f)|0dn)E  
} Rfc&OV  
} %Fg8l{H3  
//负责部分文件的抓取 ,e FQ}&^A  
**FileSplitterFetch.java P"uHtHK  
*/ 8H#c4%by)  
package NetFox; Owpg]p yVD  
,PMb9 O\B  
!8@rK$DB  
import java.io.*; E}' d,v#Z{  
import java.net.*; n~ >h4=h  
+F~0\#d  
&<V_[Wh"  
public class FileSplitterFetch extends Thread { T[XP\!z]B!  
\_Kt6=  
"gvw0)  
String sURL; //File URL h@,e`Z  
long nStartPos; //File Snippet Start Position IO!1|JMr6  
long nEndPos; //File Snippet End Position )=E~CpKV  
int nThreadID; //Thread's ID ,J (5@8(>a  
boolean bDownOver = false; //Downing is over T$^>Fiz{Se  
boolean bStop = false; //Stop identical wz*A<iU  
FileAccessI fileAccessI = null; //File Access interface #}!>iFBcH  
r d6F"W  
Ls>u` hG  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8yWu{'G  
{ 5\w=(c9A  
this.sURL = sURL; 8f,'p}@!d  
this.nStartPos = nStart; mo#0q&ZQ  
this.nEndPos = nEnd; HA9Nr.NqC@  
nThreadID = id; =tc`:!$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |aS~"lImh  
} Cj !i)-  
<duBwkiG  
/iTUex7T  
public void run() >1r[]&8  
{ B221}t  
while(nStartPos < nEndPos && !bStop) |)?aH2IL  
{ K Z!N{.Jk  
1t[;`iZ  
fATA%eA8;  
try{ H6ky)kF&  
URL url = new URL(sURL); HZDaV&)@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {yHB2=nI  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0^&(u:~  
String sProperty = "bytes="+nStartPos+"-"; RO%tuU,-  
httpConnection.setRequestProperty("RANGE",sProperty); K=c=/`E  
Utility.log(sProperty); c8-69hb?  
sWsG,v_  
-eR!qy:.]5  
InputStream input = httpConnection.getInputStream(); DrCWvpudd  
//logResponseHead(httpConnection); :otY;n-  
[W9e>Nsp0  
V5u}C-o  
byte[] b = new byte[1024]; D/S>w(=  
int nRead; M9Nk=s! 3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qIDWl{b<  
{ hY.e[+  
nStartPos += fileAccessI.write(b,0,nRead); jSie&V@px  
//if(nThreadID == 1) /o|PA:6J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xTJ Sr2f  
} #a(%(k S  
M<A;IOpR+  
`J>E9p<  
Utility.log("Thread " + nThreadID + " is over!"); '&-5CpDUs  
bDownOver = true; #QTfT&m+G}  
//nPos = fileAccessI.write (b,0,nRead); \!UF|mD^tG  
} jr, &=C(  
catch(Exception e){e.printStackTrace ();} DJViy  
} "ep`  
} ASKAgU"h  
.'^6QST  
YPha9M$AgU  
//打印回应的头信息 K0 O-WJ  
public void logResponseHead(HttpURLConnection con) `Di ^6UK(  
{ fiE>H~  
for(int i=1;;i++) G2CZwm{/f  
{ FJsK5-  
String header=con.getHeaderFieldKey(i); E!zd(  
if(header!=null) %\}dbYS '  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); | rE!  
Utility.log(header+" : "+con.getHeaderField(header)); r,2Xu  
else "x#]i aDjf  
break; L_THU4^j  
} mL:m;>JJ n  
} DKy >]Hca  
~\IF9!  
$ \Q<K@{  
public void splitterStop() / h}PEu3y  
{ I.^X2  
bStop = true; eJU;*] xfH  
} y|q@;*rGNa  
jlu`lG*e&  
(NH8AS<  
} 6=ZRn gQ  
Q`.'-iq  
xwTijSj  
/* `z9)YH  
**FileAccess.java N]1V1c$G*  
*//文件访问(定位,写) 1YOg1 n+k  
package NetFox; NuC-qG#  
import java.io.*; = EQN-{#  
w^06z,  
On#;)35M  
public class FileAccessI implements Serializable{ L;/9L[s,  
LP.HS'M~u  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Sm$p\ORa  
RandomAccessFile oSavedFile; h5L=M^z!>  
long nPos; !]$V9F{K  
WGH%92  
U7^7/s/.  
public FileAccessI() throws IOException 9#v-2QY  
{ F>(qOH.I  
this("",0); E rr4 %-  
} <Z{vC  
:PgF  
7JbY}@  
public FileAccessI(String sName,long nPos) throws IOException =nJ{$%L\x,  
{ Z5((1J9  
oSavedFile = new RandomAccessFile(sName,"rw"); jCU=+b=  
this.nPos = nPos; \Dn&"YG7  
oSavedFile.seek(nPos); z%OuI 8"'  
} R=!kbBK>\  
Q;4}gUmI$  
FoE|Js  
public synchronized int write(byte[] b,int nStart,int nLen) xDR9_  
{ 60xa?8<cg  
int n = -1; K@B" ]6  
try{ <^d!Vzr]  
oSavedFile.write(b,nStart,nLen); cNe0x2Z$?  
n = nLen; L ;6b+I  
} hS4.3]ei  
catch(IOException e) dZPW2yf  
{ x>}B#  
e.printStackTrace (); )VNM/o%Q  
} lc]V\ 'e  
z)}3**3'y  
oFWt(r   
return n; +`ai1-vw  
} ZAMeqPt  
DW#Bfo  
,Kuk_@(}5~  
} W%TQYR  
1Fv8T'  
T YYp"wx  
/* G 0hYFc u  
**SiteInfoBean.java @&;(D!_&  
*/ Z+ixRch@-s  
package NetFox; v2d<o[[C  
?-pi,O~(p  
BWWq4mdb{  
public class SiteInfoBean { hw;0t,1  
'iJDWxCD  
=/[ltUKs:a  
private String sSiteURL; //Site's URL JjQ8|En  
private String sFilePath; //Saved File's Path T'E ] i!$  
private String sFileName; //Saved File's Name 2+z1h^)W  
private int nSplitter; //Count of Splited Downloading File )B6# A0  
1!vPc93 $$  
R,%_deV\(  
public SiteInfoBean() YydA6IK4  
{//nSplitter的缺省值为5 ?]^zD k@~  
//default value of nSplitter is 5 @<2d8ed  
this("","","",5); R~)ybf{  
} nP<S6:s:  
K}x_nW  
#<4--$Xo  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ylu2R0] (  
{ t-WjL@$F/  
sSiteURL= sURL; tR1FO%nC  
sFilePath = sPath; wxE?3%.j\  
sFileName = sName; {(4# )K2g%  
this.nSplitter = nSpiltter; Wbe0ZnM]  
C}q>YRubZ  
-ey)J +?t  
} TjxA#D)   
L1sqU-gt  
$/+so;KD  
public String getSSiteURL() } ~| k  
{ ^-hErsK  
return sSiteURL; @D~B{Hg  
} ,9d9_c.T  
/%!~x[BeJ>  
e'34Pw!m  
public void setSSiteURL(String value) Pe}PH I  
{ yY Y Nu`  
sSiteURL = value; L;S}s, 2x  
} qy ,"X)^#  
?n.)&ZIx0  
qNxB{0(D  
public String getSFilePath() VevNG *  
{ Fi4UaJ3K  
return sFilePath; rFey4zzz  
} pLnB)z?  
h./P\eDc  
yoQ\lk  
public void setSFilePath(String value) C`QzT{6!  
{ =\Iu$2r`  
sFilePath = value; z<B CLP  
} ='}#`',  
RP! X8~8  
)u*^@Wo  
public String getSFileName() GKZN}bOm\  
{ ?iv=53<c#  
return sFileName; :HRT 2I  
} y(5:}x&E  
jZd}O C<  
n *<v]1  
public void setSFileName(String value) .po>qb6  
{ o_f-GO  
sFileName = value; e\F} q)_  
} G>w+#{(  
"$|Zr  
BtsdeLj|  
public int getNSplitter() vN65T$g7  
{ n-J2/j  
return nSplitter; dz-y}J11  
} t> xd]ti  
(RE2I  
Q9c)k{QZ  
public void setNSplitter(int nCount) #H~_K}Ks  
{ \S ."?!U  
nSplitter = nCount; booRrTS  
} 6o=G8y  
} gl8Ib<{  
Q`ME@vz  
S_ b/DO  
/* Xj@+{uvQB  
**Utility.java `)K y0&?  
*/ \+m$  
package NetFox; *jITOR!uF`  
pK}=*y~$  
8Lz]Z h=ZU  
public class Utility { B{MaMf)  
V5p0h~PK  
jVWK0Zba  
public Utility() qf#)lyr<D6  
{ },@``&e  
5MF#&v  
C&<~f#lB  
} pHC /(6?  
.c+9P<VmC}  
//线程睡眠 QkQ!Ep(  
public static void sleep(int nSecond) :Ht; 0|[H  
{ 28I^$> [  
try{ Z7a945Jd  
Thread.sleep(nSecond); l dqLM  
} FwG!>  
catch(Exception e) <RXwM6G2  
{ pQa:pX  
e.printStackTrace (); ' cIEc1y  
} /7"I#U^u/  
} [k<1`z3  
{tiKH=&J  
//日志 f&KdlpxKv  
public static void log(String sMsg) ,$lemH1d  
{ i=S~(gp  
System.err.println(sMsg); "ju'UOcS/  
} iE].&>w  
F@YKFk+a  
WFTvOFj  
public static void log(int sMsg) G`0V)S  
{ viX +|A4gJ  
System.err.println(sMsg); g>JLDQdc  
} K.~q+IYP[  
} q v*7K@  
@N@F,~[RR2  
3gEMRy*+  
/* 9=`Wp6Gmn  
**TestMethod.java p@ NaD=9  
*/ pzZk\-0R  
package NetFox; oUZoj2G1  
2JGL;U$  
EgjR^A1W2  
public class TestMethod { XvTCK>1  
hX:"QXx  
\ 0W!4D  
public TestMethod() U8$4 R,+  
{ ///xx/weblogic60b2_win.exe Mkxi~p%<r  
try{ WKfkKk;G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cVnJ^*Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /]^#b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^D%Za'  
fileFetch.start(); zP\7S}p7%  
} )!:sFa 1  
catch(Exception e){e.printStackTrace ();} M5357Q  
Z @ dC+0[=  
')Y'c  
} "qz3u`[o  
'a6<ixgo0  
O^Q7b7}y  
public static void main(String[] args) nI.x  
{ :Qt  
new TestMethod(); 8,P- 7^  
} dP?Ge}  
} fxaJZz$o  
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