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http断点续传简单实现(java)

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/* ylQj2B,CB  
**SiteFileFetch.java CgYX^h?Y9  
*/ WW &Wh<4  
package NetFox; kLU-4W5t  
import java.io.*; V'MY+#  
import java.net.*; yBIX<P)vE'  
yTZ o4c "  
9|v%bO  
public class SiteFileFetch extends Thread { }^p<Y5{b  
oM Z94 , 3  
|\G^:V[.  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1+XM1(|c`  
long[] nStartPos; //开始位置 cGdYfi  
long[] nEndPos; //结束位置 yO!M$aOn/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nbf/WOCk  
long nFileLength; //文件长度 ]t`SCsoo  
boolean bFirst = true; //是否第一次取文件 gTU5r4xm~  
boolean bStop = false; //停止标志 B.~] 7H5"(  
File tmpFile; //文件下载的临时信息 ; D/6e6  
DataOutputStream output; //输出到文件的输出流 dl6U]v=  
e3~{l~ Rb  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) <'SS IMr  
public SiteFileFetch(SiteInfoBean bean) throws IOException %9Z0\ a)[  
{ kw]?/s`  
siteInfoBean = bean; G'PZ=+!XO/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6yMZ2%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _*Z3,*~"X  
if(tmpFile.exists ()) e6J^J&`|4  
{ 7Zd g314  
bFirst = false; !jSgpIp  
read_nPos(); ()O&O+R|)  
} \]5I atli  
else /sT?p=[.  
{ ctLNzJes%  
nStartPos = new long[bean.getNSplitter()]; 2{vAs  
nEndPos = new long[bean.getNSplitter()]; [Z#Sj=z  
} 5\#I4\  
>0<n%V#s:r  
B%MdJ D>  
pq&[cA_w  
} K%x]:|,>M  
g,]m8%GHE  
J@6j^U  
public void run() -C3[:g  
{ 6l;2kztGp  
//获得文件长度 DF4CB#  
//分割文件 %!(C?k!\  
//实例FileSplitterFetch PM#3N2?|E  
//启动FileSplitterFetch线程 /WE\0bf  
//等待子线程返回 *vuI'EbM  
try{ 4"(rZWv  
if(bFirst) Dd pcov  
{ O#=%t  
nFileLength = getFileSize(); -eyF9++`  
if(nFileLength == -1) dM= &?g  
{ s- PS]l@  
System.err.println("File Length is not known!"); {5<fvMO!6  
} >V27#L2:J  
else if(nFileLength == -2) bp=r]nO  
{ 4R\jZ@D  
System.err.println("File is not access!"); p^RX<L/\=_  
} !|H,g wqU  
else yV\%K6d|3&  
{ 1Kk6n UIN  
for(int i=0;i<nStartPos.length;i++) Abt<23$h  
{ PS+~JwDUc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NLG\*mQ  
} Q!V:=d  
for(int i=0;i<nEndPos.length-1;i++) S_Wq`I@b  
{ 1Z @sh>X|  
nEndPos = nStartPos[i+1]; s_VcC_A  
} 9*ZlNZ  
nEndPos[nEndPos.length-1] = nFileLength; sg2%BkTI  
} E1OrL.A6  
} mY4pvpZw8  
R )Arr77  
 #O\as~-  
//启动子线程 $Vq5U9-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xn503,5G*7  
for(int i=0;i<nStartPos.length;i++) 5}ftiy[Yc  
{ :ZIa   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pa+'0Y]71  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -kMw[Y  
nStartPos,nEndPos,i); 1*dN. v:5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c:7F 2+p  
fileSplitterFetch.start(); n-" (~  
} ka\{?:r,8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W3/bM>1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $KGMAg/H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fPUr O  
nEndPos = " + nFileLength); VYkh@j  
// fileSplitterFetch[nPos.length-1].start(); 89(qU  
pQ:^ ziwa3  
1Ng.Ukb  
//等待子线程结束 Z}uY%]  
//int count = 0; ~at@3j}W  
//是否结束while循环 /u4RZ|&as  
boolean breakWhile = false; 'A7!@hVy  
8lYA6A  
wPjq B{!Q  
while(!bStop) ZxwrlaA  
{ %N<5ST>(  
write_nPos(); `M6"=)twu  
Utility.sleep(500); jo<xrn\  
breakWhile = true; HC6U_d1-6  
EXr2d"  
JpC=ACF  
for(int i=0;i<nStartPos.length;i++) X_o#!  
{ e,e(t7c?d  
if(!fileSplitterFetch.bDownOver) /h+ W L  
{ .k]`z>uv  
breakWhile = false; 6Lq`zU^  
break; v-3VzAd=*&  
} nXLz<wE  
} '@.6Rd 8  
if(breakWhile) znsQ/[  
break; zY_J7,0g  
G^k'sgy.  
5+M,X kg  
//count++; `5?0yXK  
//if(count>4) L?d?O  
// siteStop(); }h45j84)  
} <WZ{<'ajI  
?Te#lp;`~  
u_^mN9h  
System.err.println("文件下载结束!"); IRm}?hHf  
} nD BWm`kN  
catch(Exception e){e.printStackTrace ();} t[`LG)  
} Gg'!(]v  
]i.N'O<p  
QX<n^W  
//获得文件长度 A,<5W }  
public long getFileSize() {wz)^A sy  
{ ,^?g\&f(  
int nFileLength = -1; 1]Xx {j<  
try{ mcd{:/^?  
URL url = new URL(siteInfoBean.getSSiteURL()); wG[n wt0L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Pl:4`oY3  
httpConnection.setRequestProperty("User-Agent","NetFox"); M=Ze)X\E*'  
DlUKhbo$g  
Q`9c/vPU  
int responseCode=httpConnection.getResponseCode(); UXBWCo;-  
if(responseCode>=400) '/u|32  
{ #MA6eE'R  
processErrorCode(responseCode); sWr;%<K  
return -2; //-2 represent access is error p6<JpW5@_  
} Ux=~-}<-w  
#("M4}~  
,yGbMOV  
String sHeader; > k\pSV[  
@\y{q;  
O] PM L`  
for(int i=1;;i++) uMw6b=/U  
{ Q&]|W Xv  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w/*G!o- <  
//Utility.log(in.readLine()); toPbFU'  
sHeader=httpConnection.getHeaderFieldKey(i); 7?whxi Qs  
if(sHeader!=null) #]jl{K\f#X  
{ ,6{z  
if(sHeader.equals("Content-Length")) MWv@]P_0p!  
{ a -Pz<*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'Eur[~k  
break; ev;&n@k_I  
} )\Q(=:  
} D;> 7y}\  
else 'z8FU~oU  
break; t,f ec>.  
} uM`i!7}  
} jlj ge=#c2  
catch(IOException e){e.printStackTrace ();} )ovAGO  
catch(Exception e){e.printStackTrace ();} .b]s Q'  
"KP]3EyPc  
~ZVz sNrx  
Utility.log(nFileLength); 6U !P8q  
nm1dd{U6^  
d78 [(;  
return nFileLength; @6'~RD.  
} 5K1cPU~o_b  
O"'xAPQW  
v'S]g^  
//保存下载信息(文件指针位置) &K0b3AWc  
private void write_nPos() `CVkjLiy  
{ B%6cgm,  
try{ Kz42AC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z='%NZY  
output.writeInt(nStartPos.length); 0beP7}$  
for(int i=0;i<nStartPos.length;i++) /X_L>or  
{ #Q!Xz2z2  
// output.writeLong(nPos); m:h6J''<Z*  
output.writeLong(fileSplitterFetch.nStartPos); **h4M2'C  
output.writeLong(fileSplitterFetch.nEndPos); AZQQge  
} ?) y}HF  
output.close(); 5=C?,1F$A  
} !Sn|!:N4  
catch(IOException e){e.printStackTrace ();} x\G%  
catch(Exception e){e.printStackTrace ();} m*]`/:/X[  
} i=#`7pt%'a  
$b|LZE\bU.  
+ kMj|()>\  
//读取保存的下载信息(文件指针位置) :u,.(INB  
private void read_nPos() D:Q#%wJ  
{ Vq+7 /+2"  
try{ R)66qRf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *eoH"UFYQ#  
int nCount = input.readInt(); d/9YtG%q  
nStartPos = new long[nCount]; m&gd<rt/  
nEndPos = new long[nCount]; 3l<qcKKc  
for(int i=0;i<nStartPos.length;i++) ~QbHp|g  
{ P_5aHeiJ  
nStartPos = input.readLong(); qhY+<S9  
nEndPos = input.readLong(); wL8j i>"  
} K2Abu?  
input.close(); /7D5I\  
} .JLJ(WM  
catch(IOException e){e.printStackTrace ();} teS>t!d  
catch(Exception e){e.printStackTrace ();} "/6#Z>y  
} 1k6asz^T  
OY{fxBb  
{C 5:as  
private void processErrorCode(int nErrorCode) eP]y\S*P  
{ #1haq[Uv7  
System.err.println("Error Code : " + nErrorCode); /iO"4%v  
} u*@R`,Y   
+H3~Infr4f  
f`Fj-<v  
//停止文件下载 ch8VJ^%Ra1  
public void siteStop() #4m5 I="  
{ VF2,(f-*  
bStop = true; 6#U~>r/  
for(int i=0;i<nStartPos.length;i++) ]!AS%D`  
fileSplitterFetch.splitterStop(); FXBmatBck  
~k&b  
I4N7wnBp  
} zU!{_Ao9  
} J`5+Zngr  
//负责部分文件的抓取 bpBn3f`?*  
**FileSplitterFetch.java Z(6.e8fK  
*/ tAN!LI+w  
package NetFox; oUnb-,8n  
9$$  Ijf  
F)cCaE;  
import java.io.*; 4nm.ea|  
import java.net.*; ^rJTlh 9  
5.5kH$;>  
|/K| Vwa  
public class FileSplitterFetch extends Thread { <}WSYK,zUY  
hn2:@^=f  
.F7?}8>Z  
String sURL; //File URL w0g@ <( 3  
long nStartPos; //File Snippet Start Position v>LK+|U  
long nEndPos; //File Snippet End Position YxM\qy {Vr  
int nThreadID; //Thread's ID @FIL4sb  
boolean bDownOver = false; //Downing is over #[M^Q h  
boolean bStop = false; //Stop identical ywp_,j9F  
FileAccessI fileAccessI = null; //File Access interface c(=>5  
zY\u" '4  
PFp!T [)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException IQ<G .  
{ Sk53Lc  
this.sURL = sURL; :(XyiF<Ud  
this.nStartPos = nStart; TQO|C?  
this.nEndPos = nEnd; ^rfR<Q`  
nThreadID = id; 1SjVj9{:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :? B4q#]N  
} <2]h$53y!  
CCG 5:xS  
fh`Y2s|:7R  
public void run() 6k0Awcr  
{ nX:E(9q7c  
while(nStartPos < nEndPos && !bStop) 9!=4}:+  
{ ,5zY1C==Ut  
6kp)'wz`  
A~Sc ] M  
try{ +>C26Q  
URL url = new URL(sURL); Y[L,rc/j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |5(un#  
httpConnection.setRequestProperty("User-Agent","NetFox"); _XZK2Q[  
String sProperty = "bytes="+nStartPos+"-"; q}Po)IUT`5  
httpConnection.setRequestProperty("RANGE",sProperty); =* 'yGB[x)  
Utility.log(sProperty); s7yKx g+`{  
!y_L~81?  
)>h3IR  
InputStream input = httpConnection.getInputStream(); &5K3AL  
//logResponseHead(httpConnection); uH$hMg  
!PoyM[Z"f  
=T3{!\tH  
byte[] b = new byte[1024]; (QIU3EN  
int nRead; 4OM ]8I!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1 0zM8<bl  
{ x3Cn:F  
nStartPos += fileAccessI.write(b,0,nRead); UZt3Ua&J  
//if(nThreadID == 1) &c-V QP(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Po=:-Of:  
} ,9G'1%z,  
xytWE:=  
H9jlp.F  
Utility.log("Thread " + nThreadID + " is over!"); {G=>WAXo  
bDownOver = true; 5(#z)T  
//nPos = fileAccessI.write (b,0,nRead); 8-+# !]  
} ]uhG&: }  
catch(Exception e){e.printStackTrace ();} $xW9))  
} 0(c,J$I]Z!  
} &kd W(;`  
S".|j$  
<P1nfH  
//打印回应的头信息 R5b,/>^'A  
public void logResponseHead(HttpURLConnection con) MMjewGxe  
{ ):G+*3yb  
for(int i=1;;i++) /|U;_F Pmc  
{ +xIVlH9`Q  
String header=con.getHeaderFieldKey(i); 2 Ax(q&`9  
if(header!=null) dKPXs-5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "8a V~]~Dj  
Utility.log(header+" : "+con.getHeaderField(header)); R{brf6,  
else ]z7pa^  
break; J" ,Cwk\  
} >1Iw!SO+  
} [i~@X2:Al  
Z-t qSw8n  
pDP* 3  
public void splitterStop() 6$PQ$  
{ =^M Q 4  
bStop = true; b/.EA' /  
} TQt[he$O  
d^?e*USh  
|o eg'T  
} UBv#z&@[  
m6 M/G  
g#{7qmM  
/* $n8&5<  
**FileAccess.java Dp*:oMATx0  
*//文件访问(定位,写) @QJPcF"  
package NetFox; i`9}">7v~  
import java.io.*; &gV9h>Kc#  
hHMp=8J7  
q\P{h ij  
public class FileAccessI implements Serializable{ 7KC2%s#7  
FFwu$S6e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :p<:0W2!  
RandomAccessFile oSavedFile; /3 L4K  
long nPos; G| &$/]~  
 [Ketg  
C.=%8|Zy  
public FileAccessI() throws IOException }rVLWt  
{ N["M "s(N  
this("",0); J|V*g]#kP  
} :ldI1*@i<  
JvT#Fxjk  
=`}|hI   
public FileAccessI(String sName,long nPos) throws IOException <vg|8-,#m  
{ V:D?i#%,z  
oSavedFile = new RandomAccessFile(sName,"rw"); !=vsY]  
this.nPos = nPos; !+hw8@A  
oSavedFile.seek(nPos); /$qB&OWJn  
} 0^P9)<k'  
A@.ruG$  
, Z1 &MuV  
public synchronized int write(byte[] b,int nStart,int nLen) rIv#YqT  
{ F9_X^#%L  
int n = -1; z2.OR,R}]  
try{ ODCN~7-@  
oSavedFile.write(b,nStart,nLen); H-& ktQWK3  
n = nLen; xjDaA U,  
} q/7T-"q/G  
catch(IOException e) L{f0r!d|  
{ *~#`LO  
e.printStackTrace (); {R~L7uR @O  
} M1DV9~S  
;cv\v(0  
)1 0aDTlr  
return n; QSYKYgxC  
} `+(JwQC4  
EffU-=?%!  
Hg]iZ,8?  
} %E":Wv  
>\Iy <M  
Em<J{`k6  
/* 5n2}|V$VqP  
**SiteInfoBean.java a,t]>z95  
*/ rt! lc-g%/  
package NetFox; zW95qxXg  
65c#he[_Y  
fxD|_  
public class SiteInfoBean { vf<Tq  
}WNgKw  
]waCYrG<sY  
private String sSiteURL; //Site's URL <ot%>\C  
private String sFilePath; //Saved File's Path :;3y^!  
private String sFileName; //Saved File's Name @:u2{>Yl  
private int nSplitter; //Count of Splited Downloading File 5)K?:7  
=-uk7uZM  
7:)$oH  
public SiteInfoBean() Z+;670Z  
{//nSplitter的缺省值为5 V,3$>4x  
//default value of nSplitter is 5 1B`0.M'd  
this("","","",5); O;;vz+ j  
} ^@q $c  
V/DdV}n!  
P4"EvdV7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }'TZ)=t{J  
{ '$CJZ`nt  
sSiteURL= sURL; {uO2m*JrI  
sFilePath = sPath; ByXcs'  
sFileName = sName; JA?P jo  
this.nSplitter = nSpiltter; / ='/R7~  
}15ooe%  
0'y3iar  
} c:`&QDF  
9y"\]G77E  
,OO0*%  
public String getSSiteURL() kasx4m]^  
{ ^p7Er!  
return sSiteURL; e,0Gc-X[B  
} dzc.s8T(0  
5zI I4ukn*  
b"#|0d0  
public void setSSiteURL(String value) [hXU$Y>"0  
{ /&'rQ`nd  
sSiteURL = value; cd*F;h  
} ,W<mz7Z(@  
r \]iw v  
wkZ}o,{*:  
public String getSFilePath() 8:0.Pi(ln@  
{ 9L xa?Y1  
return sFilePath; 9k!#5_ M  
} (A8X|Y  
5eSmyj-W  
9G}Crp  
public void setSFilePath(String value) J\kv}v  
{ "(#]H;!W  
sFilePath = value; )0Lv-Gs  
} oBTRO0.s+  
ul3._Q   
gnSb)!i>z  
public String getSFileName() {p(.ck ze+  
{ KrT+Svm  
return sFileName; H23-%+*J  
} pVm'XP  
GKKf#r74  
^cF_z}Zi+  
public void setSFileName(String value) =h 2zIcj  
{ "S@%d(lg  
sFileName = value; ~nG?>  
} {__"Z<  
6rOd80\  
sjV>&eb  
public int getNSplitter() !j?2HlIK+  
{ _/5mgn<GK  
return nSplitter; H{ CG/+x  
} E7qk>~Dg  
 qTL]  
miZ&9m  
public void setNSplitter(int nCount) aE( j_`L78  
{ jDO[u!J6.%  
nSplitter = nCount; J0M7f]  
} *:3`$`\54  
} ( XoL,lJ  
 Ju#t^P  
H:BWv08~5  
/* A/EW57v"  
**Utility.java %g4G&My@J  
*/ >;.'$-  
package NetFox; (r?41?5K  
{1V~`1(w  
)xuvY3BPB?  
public class Utility { Pp[?E.]P  
v(/T<^{cuk  
Zi fAn  
public Utility() T Prqb  
{ Gt^Fj&^  
u<l[S  
Wo@0yF@  
} o'Byuct  
UmSy p\i  
//线程睡眠 K$dSg1t  
public static void sleep(int nSecond) |A#pG^  
{ @e_ bG@  
try{ lXS.,#lp  
Thread.sleep(nSecond); T8 ,?\7)S9  
} tTB,eR$  
catch(Exception e) 4jl UyAD  
{ I=)u:l c  
e.printStackTrace (); O$ 7R<V  
} %(,Kj ~0  
} *eAsA(;  
i[_WO2  
//日志 C$~2FTx  
public static void log(String sMsg) >'^Tp7\  
{ Uv~r]P)  
System.err.println(sMsg); Y9)uy 8c  
} %OeA"#  
<0r2m4z  
w NlC2is  
public static void log(int sMsg) mjDaus59  
{ 'Tn i;  
System.err.println(sMsg); 8[Ssrk  
} h|tdK;)  
} VFj}{Y  
VL5GX (  
o.ntzN  
/* P".CZyI-i  
**TestMethod.java TzT(aWP"  
*/ v"VpE`z1#  
package NetFox; }j^asuf~c  
?CgqHmf\\(  
'`#sOH  
public class TestMethod { IvFxI#.ju  
l&@]   
B zmmE2~*  
public TestMethod() A{Jp>15AVg  
{ ///xx/weblogic60b2_win.exe diF-`~  
try{ p0jQQg  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YL_M=h>P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |N%?7PZ(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fz[o;GTc  
fileFetch.start(); kQ5mIJ9(  
} LD]a!eY  
catch(Exception e){e.printStackTrace ();} slC 38  
n.&z^&$w\)  
9?5'>WO  
} b*w@kLLN  
?6;9r[ p  
W_:3Sj l'  
public static void main(String[] args) i^9,.$<1  
{ =]k0*\PS  
new TestMethod(); ),ur! v  
} LO8`qq*rq  
} SJg4P4|  
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