http断点续传简单实现（java)

/* n^Au*'  
**SiteFileFetch.java /Y^7Rl  
*/ V9$-twhu  
package NetFox; .5k^f5a  
import java.io.*; M7H~;S\3IM  
import java.net.*; xucIjPi]
 
7+]F^ 6  
B=x~L  
public class SiteFileFetch extends Thread { T.euoFU{Z  
uk{J@&F
 
G+Ei#:W,  
SiteInfoBean siteInfoBean = null; //文件信息Bean ;G$)MS'nB  
long[] nStartPos; //开始位置 9l=Fv6  
long[] nEndPos; //结束位置 g
x&73f<J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #y`k$20"  
long nFileLength; //文件长度 e6es0D[>5  
boolean bFirst = true; //是否第一次取文件 - coy@S=.'  
boolean bStop = false; //停止标志 ~g96o81V  
File tmpFile; //文件下载的临时信息 E#~2wqK  
DataOutputStream output; //输出到文件的输出流 Gm*Uv6?H?  
NFM-)Z57  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h&'J+b  
public SiteFileFetch(SiteInfoBean bean) throws IOException |=OpzCs  
{ @>9A$w$H|a  
siteInfoBean = bean; v*gLNB,ZH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H.;yLL=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?ZM^%]/+  
if(tmpFile.exists ()) Kk56/(_S  
{ cl#OvQ  
bFirst = false; `i{4cT8:  
read_nPos(); ^"/Dih\_  
} 9/QS0  
else GfQ^@Tl  
{ 0<"tl0p_  
nStartPos = new long[bean.getNSplitter()]; ^8U6"O6|X  
nEndPos = new long[bean.getNSplitter()]; OUKj@~T  
} {9,R@>R  
8s&2gn1  
Bzwx0c2VY8  
qIUC2,&g  
} zVn*!c  
#s/{u RYQ  
hG[4O3jo\  
public void run() f#2#g%x  
{ )m>6hk  
//获得文件长度 Wpa$B )xg  
//分割文件 EsNk<Ra  
//实例FileSplitterFetch PH{c,  
//启动FileSplitterFetch线程 pIrv$^  
//等待子线程返回 ]b!R-G!gV  
try{ >pJ6{Ip  
if(bFirst) cEtZ}2,j  
{ (O<abB(  
nFileLength = getFileSize(); aq$62>[  
if(nFileLength == -1) :0|Hcg  
{ iu+zw[f  
System.err.println("File Length is not known!"); jm~mhAE#  
} ge@reGfsB1  
else if(nFileLength == -2) GZ}*r{  
{ vJzxPy|  
System.err.println("File is not access!"); G-ZrM  
} V=Ww>  
else T\.7f~3  
{ " Tw0a!  
for(int i=0;i<nStartPos.length;i++) e*6U |+kJ  
{ )62q|c9F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eF*TLI<[^I  
} L)j]~^P$-  
for(int i=0;i<nEndPos.length-1;i++) 8p3ZF@c~t  
{ aslNlH6  
nEndPos = nStartPos[i+1]; _g^E%@'W  
} Rs^jk)Z:)  
nEndPos[nEndPos.length-1] = nFileLength; "o~N42DLB%  
} Pi^ECSzQu[  
} 8dYk3sk  
9 #.<E5:  
|A2W8b {]  
//启动子线程 @DUN;L 4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2"B}}  
for(int i=0;i<nStartPos.length;i++) n^3NA|A  
{ | 3hT{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3/yt*cr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -DbH6u3  
nStartPos,nEndPos,i); GC,vQ\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?T$*5d  
fileSplitterFetch.start(); :H~UyrN  
} AD0ptHUBa  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1 yxZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X=-gAutfE=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ze-TBh/  
nEndPos = " + nFileLength); JsHxQ0Tw  
// fileSplitterFetch[nPos.length-1].start(); ^/ULh,w!fP  
)@sJTAK  
RcKQER  
//等待子线程结束 m&(%&}g  
//int count = 0; :%+^}   
//是否结束while循环 Ki&WS<,0Z  
boolean breakWhile = false; `bBfNI?3d*  
mRg ,A\  
\pT^Zhp)  
while(!bStop) $l0eI  
{ 58a)&s[+  
write_nPos(); Vq?8u/  
Utility.sleep(500); FCUVP,"T  
breakWhile = true; rQ9?N^&!%  
}L{_xyi>#  
Y#Sd2h,^X  
for(int i=0;i<nStartPos.length;i++) #3 }5cC8_  
{ ?[a7l:3-[  
if(!fileSplitterFetch.bDownOver) .If"'hMY  
{ )Gu0i7iN  
breakWhile = false; F}VS)  
break; \#IJ=+z  
} d&$.jk8 2  
} Q6e'0EIKC  
if(breakWhile) (25^r  
break; -&f]X
u  
EU&6Tg  
]
x5(bnWx  
//count++; GgZEg ?@  
//if(count>4) >b/k|?xP  
// siteStop(); `2Z4#$.  
} QiQ2XW\E  
i`ZHjW~`  
Q0[CH~  
System.err.println("文件下载结束！"); >Rz#g*@E  
} M+;!]tbc3  
catch(Exception e){e.printStackTrace ();} Q8M:7#ySji  
} w|K(>5nz  
%nG~u,_2f  
3.GdKP.%  
//获得文件长度 `CTkx?e[  
public long getFileSize() ]ouUv7\  
{ )edU <1P  
int nFileLength = -1; xC=3|,U  
try{ E@'CU9Fo  
URL url = new URL(siteInfoBean.getSSiteURL()); d=.n|rS4 W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jN5} 2 p*  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;OT#V,}r  
2:6Y83  
_dJVnC1 !  
int responseCode=httpConnection.getResponseCode(); o0-fUCmC  
if(responseCode>=400) t2!$IH
E:  
{ h~^qG2TYWq  
processErrorCode(responseCode); ;_Of`C+  
return -2; //-2 represent access is error %i]uW\~U  
} v"Ud mv"  
D KMbs  
X,C/x)  
String sHeader; ><:lUt*N2  
jmA{rD W  
Cs6zv>SR  
for(int i=1;;i++) dmTW]P2  
{ G74a9li@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RfVV(X  
//Utility.log(in.readLine()); hBYh90]  
sHeader=httpConnection.getHeaderFieldKey(i); ,sRrV $,"  
if(sHeader!=null) O. .@<.  
{ ~[ ks|  
if(sHeader.equals("Content-Length")) Cs~\FI1wR  
{ L2V $%*6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); aLyhxmn ^)  
break; d q+7K  
} VUg~[  
} d9Ow 2KrC  
else qkR,<"C|`  
break; y>pq*i  
} FclSuQWti  
} yg]nS<K~4  
catch(IOException e){e.printStackTrace ();} [gg7Z|Hu  
catch(Exception e){e.printStackTrace ();} 51FK~5  
?'8MI|*l%  
aaa#/OWQZ  
Utility.log(nFileLength); /9vMGef@  
59%f|.Z)  
s+\qie  
return nFileLength; XQg%*Rw+t  
} cO"Xg<#y  
>-./kI "  
+ke42Jwt  
//保存下载信息（文件指针位置） =ty@xHr  
private void write_nPos() M$5%QM}  
{ 0z<]\a4  
try{ 5M.n'*   
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4|o{_g[  
output.writeInt(nStartPos.length); aR(Z~z;C  
for(int i=0;i<nStartPos.length;i++) q0KXuMK  
{ J9KLO=  
// output.writeLong(nPos); bZ@53  
output.writeLong(fileSplitterFetch.nStartPos); Xy(SzJ%  
output.writeLong(fileSplitterFetch.nEndPos); D*2
p  
} pmpn^ZR  
output.close(); sR0e&Y  
} qKb-aP-  
catch(IOException e){e.printStackTrace ();} !kk %;XSZ  
catch(Exception e){e.printStackTrace ();} gm%bxr@X~  
} S5[RSAbf*t  
\kJt@ [w%  
0f}Q~d=QL  
//读取保存的下载信息（文件指针位置） '>lPq tdZ  
private void read_nPos() (P52KD[A[  
{ Ok{:QA~#  
try{ _F$t#.o  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +\(ay"+ d  
int nCount = input.readInt(); s)'_{ A"h  
nStartPos = new long[nCount]; `]
 dx%  
nEndPos = new long[nCount]; {p_vR/yN  
for(int i=0;i<nStartPos.length;i++) dmMr8-w  
{ #*aGzF  
nStartPos = input.readLong(); tH|Q4C  
nEndPos = input.readLong(); A **
M"T  
} =K<I)2   
input.close(); !Pjg&19  
} -D^y)  
catch(IOException e){e.printStackTrace ();} CCvBE, ux  
catch(Exception e){e.printStackTrace ();} p(&o'{fb  
} Y`_X@Q  
{*r$m>HpM  
<}'B-k9  
private void processErrorCode(int nErrorCode) VNEZBy"F  
{ Ru\Lr=9  
System.err.println("Error Code : " + nErrorCode); JX,#W!d  
} 1AkHig,  
Y
M/3VD  
rOf  
//停止文件下载 )Ai%wCzw*  
public void siteStop() F p=Q$J|  
{ `g:^KCGMM  
bStop = true; ;7=JU^@D@  
for(int i=0;i<nStartPos.length;i++) dcTM02kEh  
fileSplitterFetch.splitterStop(); Am`A[rV0  
>]08".ajS  
r^tXr[}  
} = (h;L$  
} VKJ~ZIO@A  
//负责部分文件的抓取 F^
bQ-  
**FileSplitterFetch.java xgw)`>p,W  
*/ Bst>9V&R  
package NetFox; 7a_n\]t465  
d"`
>&8*  
+6Fdi*:  
import java.io.*; &)}:Y!qiu  
import java.net.*; {gHscj;SM  
eeTaF!W  
~I
^[rP~  
public class FileSplitterFetch extends Thread { (G
Orfr  
"?(Fb
_}i  
\kGtYkctZ  
String sURL; //File URL 7tO$'q*h  
long nStartPos; //File Snippet Start Position U;dt-3?=.h  
long nEndPos; //File Snippet End Position 2o}G<7r  
int nThreadID; //Thread's ID NcMq
>n  
boolean bDownOver = false; //Downing is over , p=8tf#  
boolean bStop = false; //Stop identical IMw)X0z  
FileAccessI fileAccessI = null; //File Access interface %1+~(1P  
N}<U[nh'  
.wOLi Ms  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException JkDZl?x5  
{ 'Mhdw
}  
this.sURL = sURL; W_n.V" hN  
this.nStartPos = nStart; {%~Ec4r  
this.nEndPos = nEnd; f]65iE?x  
nThreadID = id; ewPdhCK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Bo(l!G  
} 9NXiCP9A  
d?X6x  
tpzdYokh>  
public void run() RKb3=}
*C  
{ m)2hl~o_  
while(nStartPos < nEndPos && !bStop) wyEgm:Vt  
{ [!efQap  
-"fq34v  
CKw)J}z  
try{ <Y'YpH`l  
URL url = new URL(sURL); w3UJw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _ShJ3\,K  
httpConnection.setRequestProperty("User-Agent","NetFox"); /4BXF4ksi,  
String sProperty = "bytes="+nStartPos+"-"; s(LqhF[N2]  
httpConnection.setRequestProperty("RANGE",sProperty); qinQ5t
  
Utility.log(sProperty); r>@/XYK&\  
O*CX@Ne  
uKzz
/Y{  
InputStream input = httpConnection.getInputStream(); \-id[zKb  
//logResponseHead(httpConnection); T0)y5
  
? NK}q\$  
fT~<C {  
byte[] b = new byte[1024]; )F2tV ]k\  
int nRead; `3s-\>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6_><W"r:]  
{ (pNng"/  
nStartPos += fileAccessI.write(b,0,nRead); V]cY+
4Y  
//if(nThreadID == 1) 1OeDWEcB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )O(Gw-jWE  
} 3<E$m*  
v
@SrEmg  
[cs8/Q8+  
Utility.log("Thread " + nThreadID + " is over!"); OB@t(KNx*P  
bDownOver = true; -^"?a]B  
//nPos = fileAccessI.write (b,0,nRead); `W S  
} ~H~4 fp b  
catch(Exception e){e.printStackTrace ();} 'F~SNIay  
} ;$;/#8`>  
} p5BcDYOw`  
+'4dP#  
DYl{{L8@  
//打印回应的头信息 `t2! M\)  
public void logResponseHead(HttpURLConnection con) CU&,Kq@  
{ :|Ty 0>k  
for(int i=1;;i++) \./2Qc,  
{ E#]%e^  
String header=con.getHeaderFieldKey(i); e@VRdhb  
if(header!=null) ^/,yZ:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mmK_xu~f28  
Utility.log(header+" : "+con.getHeaderField(header)); U<gw<[>f  
else Ro$XbU)  
break; ~`fB\7M  
} 9?6$2I  
} .r"?w  
9>P(eN  
[!
BH3J!  
public void splitterStop() IGQ8-#=  
{ 0~+k  
bStop = true; ((q(Q9(F  
} je%12DM  
=?aB@&  
__npX_4%S  
} #O ]IXo(5z  
aoX$,~oI5  
4!|ar?Zy  
/* \Y p oJ!-  
**FileAccess.java ~5529  
*//文件访问(定位，写) Ey%NqOs0#  
package NetFox; @]4s&;   
import java.io.*; J n/=v\K@  
nVD YAg'  
2uEu,YC  
public class FileAccessI implements Serializable{ N*W.V,6yH  
#1k,t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 
ocUu  
RandomAccessFile oSavedFile; C3gz)!3  
long nPos; _=#mmZkq  
58,mu#yq6  
;zODp+4@Q  
public FileAccessI() throws IOException "(GeW286k  
{ w ?aLWySYT  
this("",0); (H^o8J   
} LPF?\mf ^4  
&9tsk#bA.g  
@RW%EXKt  
public FileAccessI(String sName,long nPos) throws IOException Vo[4\h#$  
{ ,Nh X%  
oSavedFile = new RandomAccessFile(sName,"rw"); *ni|I@8
 
this.nPos = nPos; Cv33?l-8%_  
oSavedFile.seek(nPos); *^()
el,d  
} 4+"SG@i`W  
$la,_Sr  
Y.J$f<[R  
public synchronized int write(byte[] b,int nStart,int nLen) 0jH2.d=  
{ +>j_[O5Y  
int n = -1; g=Jfp$*[  
try{ &baY[[N  
oSavedFile.write(b,nStart,nLen); 6WZp&pO  
n = nLen; <D}k@M Z  
} ww,'n{_  
catch(IOException e) Ns(F%zkm  
{ @}:(t{>;e7  
e.printStackTrace (); fJKOuFK  
} zT"#9"["  
9"TPDU7"  
|.5d^z  
return n; Sb.;$Be5g  
} VXp X#O  
Vv]mME@  
wW~2]*n  
} PoZBiw@  
fsoS!6h0k  
SbY i|V,H  
/* ;7}*Xr|  
**SiteInfoBean.java Q>$v~v?9  
*/ b._pG(o1  
package NetFox; e6Y0
G,K  
]h
6<o*  
tEl_A"^e  
public class SiteInfoBean { RWYA`  
="4)!
 
KMa?2cJH#  
private String sSiteURL; //Site's URL va\cE*,@ns  
private String sFilePath; //Saved File's Path PQ" Dl=,  
private String sFileName; //Saved File's Name h.NA$E?7  
private int nSplitter; //Count of Splited Downloading File Sj\8$QIXC  
, {^g}d8  
%|Vq"MW,I  
public SiteInfoBean() 90a= 39kI  
{//nSplitter的缺省值为5 %"D-1&%zY  
//default value of nSplitter is 5 K9c:K/H  
this("","","",5); GmFNL/x8-v  
} hI$an%Y(  
A]1](VQ)4  
,b{4GU$3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) udMq>s;  
{ ~p&sd)  
sSiteURL= sURL; uP.3(n[&  
sFilePath = sPath; e8Jd*AKjb  
sFileName = sName; I~,*Rgv/Z  
this.nSplitter = nSpiltter; =x>KA*O1  
MFrVGEQBRL  
L,$9)`j  
} 4?`7XJ0a  
X(~NpLR  
o/&Q^^Xj^~  
public String getSSiteURL() G"]'`2.m  
{ *=rl<?tX  
return sSiteURL; @L0.Z1 ).  
} sqhM[u k  
}QK-@T@4<  
o 0B`~7(  
public void setSSiteURL(String value) gO29:L[t  
{ /1YqDK0  
sSiteURL = value; W>.qGK|l  
} ==&=3  
]'Bz%[C)  
!U@[lBW  
public String getSFilePath() K=V)"v5o3  
{ )9s[-W,e  
return sFilePath;
CAk.2C/  
} +NQw^!0qy  
B--`=@IRf"  
3LG)s:p$/  
public void setSFilePath(String value) se&:Y&vrc~  
{ RaR$lcG+iY  
sFilePath = value; (c;$^xZK  
} ;tO(,^  
IsI\T8yfc  
`3~w#?+=*  
public String getSFileName() |2Q;SaI^\  
{ uTQ/_$  
return sFileName; O:4.xe  
} opKtSF|)  
D9h\=[%e  
Hly$ Wm  
public void setSFileName(String value) Tw$lakw  
{ 4q2aVm  
sFileName = value; V
}&  
} <3'r&ks  
/p~gm\5Z  
w1[F]|  
public int getNSplitter() a!;?!f-i  
{ ?g1%-F+  
return nSplitter; F[LBQI`zq  
} RX'( l  
HA| YLj?|g  
y 2bZo'Z  
public void setNSplitter(int nCount) YDP<  
{ D+tn<\LF  
nSplitter = nCount; 6:Ra3!V"v  
} Ef69]{E  
} ) b?HK SqI  
(V*ggii@  
M^a QH/=:"  
/* Gt'%:9r  
**Utility.java I_4'9  
*/ P'[w9'B  
package NetFox; u>}k+8~  
mjfU[2  
MbYAK-l.h  
public class Utility { 6#v"+V  
ZhW>H  
Y<l{DmrsA  
public Utility() |iJ37QIM  
{ S7@.s`_{w  
&{99Owqg  
U)2\=%8  
} M '[.ay  
,u/GA<'#M  
//线程睡眠 CtS*"c,j  
public static void sleep(int nSecond) nI&Tr_"tm  
{ 72.ZE%Ue  
try{ kP3'BBd,  
Thread.sleep(nSecond); [/xw5rO%  
} lj(}{O  
catch(Exception e) KnKV+:"  
{ 7Q2"]f,$CQ  
e.printStackTrace (); r\Zz=~![<  
} J=ZNx;{6  
} <^{|5u  
|d&a&6U:  
//日志 *22}b.)  
public static void log(String sMsg) >zVj+  
{ QOMh"wC3  
System.err.println(sMsg); {'T=&`&OF  
} Q u{#4qToA  
1t6VS3  
5\lOZYHX  
public static void log(int sMsg) mJ
p)nF8r~  
{ <GT&q <4w  
System.err.println(sMsg); |}t[-a  
} ;vnG  
} \^i/:  
C[gy{40}  
CNQ>J`4  
/* yc?+L;fN  
**TestMethod.java C[z5& x2  
*/ t[|^[%i  
package NetFox; q3n(Z  
Hn+w1v&3  
rfku]A$  
public class TestMethod { ?*){%eE  
dX?8@uzu  
Q)#+S(TG  
public TestMethod() lku}I4  
{ ///xx/weblogic60b2_win.exe  `C9/=  
try{ #**vIwX-Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
2Ck'A0d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |hk?'WGc`0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gq\ulLyOeZ  
fileFetch.start(); $n.oY5=\  
} |]y]K%  
catch(Exception e){e.printStackTrace ();} :A9G>qg  
gP:
mZ7  
kdcr*7w  
} ]lV\D8#  
W{B)c?G]  
~ (I'm[  
public static void main(String[] args) !36jtKdM  
{ 4Hc+F(  
new TestMethod(); ;H}XW=vO  
} ,'N8Ivt  
} F l@%?  
点击下载更多相关资料