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http断点续传简单实现(java)

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/* ! :]_-DX  
**SiteFileFetch.java X "7CN Td  
*/ B`-uZ9k   
package NetFox; 8s6[-F5  
import java.io.*; u"qu!EY2  
import java.net.*; "j_iq"J  
0FcDO5ia  
vSnVq>-q&  
public class SiteFileFetch extends Thread { CBd%}il  
bBs{PI2(p1  
<CVX[R]U  
SiteInfoBean siteInfoBean = null; //文件信息Bean U*a#{C7"  
long[] nStartPos; //开始位置 p"hO6b%V  
long[] nEndPos; //结束位置 &5-1Cd E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 VkJ">0k  
long nFileLength; //文件长度 4nm.ea|  
boolean bFirst = true; //是否第一次取文件 29J|eBvxx  
boolean bStop = false; //停止标志 vE )N6Ss  
File tmpFile; //文件下载的临时信息 3q/Us0jr  
DataOutputStream output; //输出到文件的输出流 I]eeV+U8W  
>`03EsU  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) P{)D_Bi  
public SiteFileFetch(SiteInfoBean bean) throws IOException LKvX~68  
{ # QwX|x{  
siteInfoBean = bean; 6c]4(%8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "~ID.G|<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SOR\oZ7  
if(tmpFile.exists ()) /}@F q  
{ zY\u" '4  
bFirst = false; VvW4!1Dl  
read_nPos(); (X@\2M4@T#  
} qR cSB  
else b~&cYk'  
{ .fzyA5@l  
nStartPos = new long[bean.getNSplitter()]; D 1.59mHsD  
nEndPos = new long[bean.getNSplitter()]; Nmx\qJUR(  
} R_G2C@y*  
AHs%?5YTY;  
,mm97I  
!LH;K  
} ^4`x:6m  
CCG 5:xS  
PJZ;wqTD_  
public void run() tkV[^OeU>  
{ A]m*~Vj]  
//获得文件长度 liYsUmjZ=  
//分割文件 GImPPF  
//实例FileSplitterFetch f.J^HQ_  
//启动FileSplitterFetch线程 BaIpX<$T  
//等待子线程返回 K7 C <}y  
try{ )>h3IR  
if(bFirst) )*}\fmOv{  
{ 0Lj;t/mG  
nFileLength = getFileSize(); !PoyM[Z"f  
if(nFileLength == -1) =T3{!\tH  
{ (QIU3EN  
System.err.println("File Length is not known!"); Byw EoS  
} G h+;Vrx  
else if(nFileLength == -2) \ R}I4'  
{ gtH^'vFZ  
System.err.println("File is not access!"); U $#^ e  
} 'E#L6,&  
else H 2I  
{ !KXcg9e  
for(int i=0;i<nStartPos.length;i++) Ydsnu  
{ Q#yHH]U)X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1^o})9  
} qWK}  
for(int i=0;i<nEndPos.length-1;i++) }2LG9B%  
{ !Dc?9W!b  
nEndPos = nStartPos[i+1]; vULDKJNHX  
} GjEV]hqR  
nEndPos[nEndPos.length-1] = nFileLength; &kd W(;`  
} S".|j$  
} XC6|<pru  
pqs!kSJV  
0*]0#2Z  
//启动子线程 prO&"t >  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o]p$ w[5  
for(int i=0;i<nStartPos.length;i++) o!h::j0,~  
{ VB/75xK_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~uY5~Qs9G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U !+O+(  
nStartPos,nEndPos,i); ]z7pa^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0o7o;eN  
fileSplitterFetch.start(); >1Iw!SO+  
} [i~@X2:Al  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nZj&Ma7R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pDP* 3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rk=w~IZJ3  
nEndPos = " + nFileLength); OkQ< Sc   
// fileSplitterFetch[nPos.length-1].start(); x s6!NY  
M"c=_5P  
&:d`Pik6  
//等待子线程结束 KDg%sgRu}  
//int count = 0; /FXb,)1t  
//是否结束while循环 T^8`ji  
boolean breakWhile = false; 68~]_r.a  
1| WDbk  
D {E,XOi  
while(!bStop) Xl$r720ZJr  
{ E\4ZUGy0  
write_nPos(); uuHs)  
Utility.sleep(500); rr1,Ijh{D  
breakWhile = true; F'<XB~ &o  
7zQGuGo(  
D@w&[IF  
for(int i=0;i<nStartPos.length;i++) /FTP8XHwL)  
{ (Ms #)E  
if(!fileSplitterFetch.bDownOver) meB9 :w[m  
{ %j2:W\g:  
breakWhile = false; }cW8B"_"  
break; sn[<Lq  
} QWm g#2'  
} Rz>@G>b:  
if(breakWhile) aAu%QRq  
break; (8S+-k?  
4nd)*0{ f  
>PWDo  
//count++; :`yW^b  
//if(count>4) !=vsY]  
// siteStop(); KdlUa^}D  
} %MtaWZ  
!Y^B{bh  
A@.ruG$  
System.err.println("文件下载结束!"); }e"2Nc_UG  
} IH=%%AS  
catch(Exception e){e.printStackTrace ();} Jk<b#SZ[b  
} v>hc\H1P  
NCkrf]*F-  
jRk1Iu|7  
//获得文件长度 ywjD.od"v  
public long getFileSize() B&3@b  
{ >4lA+1JYk  
int nFileLength = -1; ] C_$zbmi  
try{ M1DV9~S  
URL url = new URL(siteInfoBean.getSSiteURL()); 4GJx1O0Ol  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^7kYG7/  
httpConnection.setRequestProperty("User-Agent","NetFox"); -k,}LJjo  
D#ED?Lqf  
PVq y\i  
int responseCode=httpConnection.getResponseCode(); #R= 6$  
if(responseCode>=400) g>?,,y6/w  
{ (=53WbOh/t  
processErrorCode(responseCode); cpq0' x\  
return -2; //-2 represent access is error ]x_14$rk  
} %[?{H} y  
Q `h@-6N  
8 =3#S'n  
String sHeader; [HRP&jr  
Xs4G#QsA J  
r)w]~)8  
for(int i=1;;i++) L~M6 ca"  
{ }WNgKw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]waCYrG<sY  
//Utility.log(in.readLine()); <ot%>\C  
sHeader=httpConnection.getHeaderFieldKey(i); :;3y^!  
if(sHeader!=null) rYyEs I#qo  
{ g3w-Le&T  
if(sHeader.equals("Content-Length")) s\ ]Rgi>w  
{ SP|Dz,o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V+y:!t`  
break; wqn }t]  
} wGpw+O  
} y?s#pSX;N  
else l0wvWv*k  
break; f;W>:`'  
} BjUz"69  
} bJ.68643  
catch(IOException e){e.printStackTrace ();} ps]s Tw  
catch(Exception e){e.printStackTrace ();} ])T_&%  
t7 $2/C  
0K^G>)l  
Utility.log(nFileLength);  0c:j wtf  
7[7Sm^Tw  
WkY>--^  
return nFileLength; ~F]If\b  
} 0>?78QL9<  
*j|BSd P  
8:UV;5@  
//保存下载信息(文件指针位置) SJI+$L\'  
private void write_nPos() D)LqkfJ}z^  
{ kKSn^q L*  
try{ 852Bh'u_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Qte'f+  
output.writeInt(nStartPos.length); `ZAGseDd~  
for(int i=0;i<nStartPos.length;i++) Kd,7x'h`E  
{ BB m;QOBU  
// output.writeLong(nPos); r \]iw v  
output.writeLong(fileSplitterFetch.nStartPos); GfT`>M?QGK  
output.writeLong(fileSplitterFetch.nEndPos); 6t6#<ts  
} !Zf)N_k  
output.close(); ,ffH:3F  
} -Z%B9ql'  
catch(IOException e){e.printStackTrace ();} 9/S-=VOe.t  
catch(Exception e){e.printStackTrace ();} U_c9T>=  
} s@bo df&  
X5D}<J2"  
H`ZUI8-  
//读取保存的下载信息(文件指针位置) jJCd2O]  
private void read_nPos() Q2/ZO2  
{ E%C02sI  
try{ T#sKld  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I_@XHhyVZ  
int nCount = input.readInt(); iY1JU -S  
nStartPos = new long[nCount]; s5ddGiZnBT  
nEndPos = new long[nCount]; Cy##+u,C  
for(int i=0;i<nStartPos.length;i++) $nbZ+~49  
{ j"8|U E  
nStartPos = input.readLong(); t.oP]_mI  
nEndPos = input.readLong(); q6v%HF-q4  
} w;Na9tR  
input.close(); 2s@<k1EdPl  
} ZMXIKN9BF#  
catch(IOException e){e.printStackTrace ();} :Yqi5CR  
catch(Exception e){e.printStackTrace ();} A#j'JA>_  
} p1L8g[\  
'PrrP3lO_~  
{ wx!~K  
private void processErrorCode(int nErrorCode) /A;!g5Y  
{ `!\`yI$!%w  
System.err.println("Error Code : " + nErrorCode); BI-xo}KI  
} @{!c [{x,T  
'Nv*ePz  
J@c)SK%2h  
//停止文件下载 k:0HsN!F9  
public void siteStop() \{[Gdj`  
{ `8%2F}x}qD  
bStop = true; ca1A9fvo  
for(int i=0;i<nStartPos.length;i++) AA$-Lx(UJk  
fileSplitterFetch.splitterStop(); dRXF5Ox5K}  
u%vq<|~-  
LCRZ<?O[|  
} {?' DZR s  
} 2!b+}+:  
//负责部分文件的抓取 R1X{=ct  
**FileSplitterFetch.java F+!K9(`|  
*/ ,9W|$2=F  
package NetFox; +,"/z\QO  
n`krK"Ii  
d&QB?yLd  
import java.io.*; B6iH[dTy_  
import java.net.*; @m[r0i0J"  
-%lA=pS{Fq  
'Bp7LtG92  
public class FileSplitterFetch extends Thread { h$EH|9HAb  
;V~[kF=t0  
c _li.]P  
String sURL; //File URL 0a??8?Q1G  
long nStartPos; //File Snippet Start Position Q9 b.]W  
long nEndPos; //File Snippet End Position E1'HdOh&z  
int nThreadID; //Thread's ID j ,' $i[F'  
boolean bDownOver = false; //Downing is over 6WQT,@ ?  
boolean bStop = false; //Stop identical c3&;Y0SD  
FileAccessI fileAccessI = null; //File Access interface h7|#7 d  
r9Wk7?w)  
 cf#2Wg)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !A )2<<4  
{ 9""e*-;Mi  
this.sURL = sURL; ? -PRS.=%  
this.nStartPos = nStart; l* =\0  
this.nEndPos = nEnd; i[_WO2  
nThreadID = id; [kIiKLX  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ZzNp#FrX"  
} x4PA~R  
B`x rdtW  
Fcc\hV;  
public void run() %o4ZD7@ '  
{ Pwn3/+"%K  
while(nStartPos < nEndPos && !bStop) \s8j*  
{ |gW>D=rkj  
0Z{f!MOh  
J2M[aibV  
try{ VFj}{Y  
URL url = new URL(sURL); }]ak6'|[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W *t+!cU/:  
httpConnection.setRequestProperty("User-Agent","NetFox"); [;`B   
String sProperty = "bytes="+nStartPos+"-"; v&p|9C@  
httpConnection.setRequestProperty("RANGE",sProperty); HrH-e= j  
Utility.log(sProperty); 5J^S-K^r  
;N4A9/)  
Wp" +\{@)  
InputStream input = httpConnection.getInputStream(); Z6eM~$Y  
//logResponseHead(httpConnection); "&s9;_9  
nCZ&FNi{O~  
5G"DgG*<  
byte[] b = new byte[1024]; u:Fa1 !4JR  
int nRead; E)l0`83~^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iYi3x_A`  
{ wJs #rkW  
nStartPos += fileAccessI.write(b,0,nRead); 7{%_6b"  
//if(nThreadID == 1) 8X,dVX5LT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !e5!8z  
} PT7-_r  
B8){  
}&+b\RE  
Utility.log("Thread " + nThreadID + " is over!"); uOzol~TU)  
bDownOver = true; RjC3wO::  
//nPos = fileAccessI.write (b,0,nRead); 'O%itCy)  
} &DQyJJ`k  
catch(Exception e){e.printStackTrace ();} .v?x>iV  
} v803@9@  
} WZ\bm$  
A dNQS  
^=f<WKn  
//打印回应的头信息 WC6yQSnY&  
public void logResponseHead(HttpURLConnection con) V(hM@ztN  
{ F7!g+LPc<  
for(int i=1;;i++) ,Jm2|WKH  
{ &\8qN_`  
String header=con.getHeaderFieldKey(i); ' U]\]Wp  
if(header!=null) x3j)'`=15  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J:<mq5[  
Utility.log(header+" : "+con.getHeaderField(header)); .E H&GX  
else 3 q1LIM  
break; 6'YT3=  
} cR'l\iv+  
} i2]7Bf)oV  
1>I4=mj  
0_F6t-  
public void splitterStop() hk6(y?#  
{ F|+Qi BO  
bStop = true; '3BBTr%aZ  
} vO>Fj  
CD}::7$  
0&M~lJ  
} 7s8-Uwl<  
-|K^!G  
<v&L90+s\;  
/* H( L.k;B  
**FileAccess.java dY=]ES} `  
*//文件访问(定位,写) cQg:yoF  
package NetFox; 5&59IA%S  
import java.io.*; z$64Ep#  
Y~E 8z  
srzlr-J  
public class FileAccessI implements Serializable{ S vTd#>ke  
{5 V@O_*{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7+!FZo{?  
RandomAccessFile oSavedFile; bVLBqa=  
long nPos; _3Kow{y\  
h^QLvOuR  
pc/x&VY%  
public FileAccessI() throws IOException p{@jM  
{ -!@]z2uU  
this("",0); ke2zxX2 f  
} .1{:Q1"S  
ttP|}|O  
|WkWZZ^  
public FileAccessI(String sName,long nPos) throws IOException 1k)31GEQw  
{ X%C`('"R  
oSavedFile = new RandomAccessFile(sName,"rw"); *XUJv&ZN  
this.nPos = nPos; 6o:b(v&Oo  
oSavedFile.seek(nPos); v[Mh[CyB  
} ltWEA  
j.]ln}b/'+  
XY`{F.2h  
public synchronized int write(byte[] b,int nStart,int nLen) at|.Q*&a#  
{ EpW89X  
int n = -1; (Sv=R(_s  
try{ p=XEMVqm  
oSavedFile.write(b,nStart,nLen); "g5<jp  
n = nLen; *w#^`yeo  
} `w8Ejm?n  
catch(IOException e) d[F3"b%  
{ PIHix{YR  
e.printStackTrace (); 49o/S2b4z  
} ,Gi%D3lA  
A3Xfu$[u  
).32Im!;#R  
return n; n-he|u  
} Mdw"^x$7  
NwcRH9};i  
x%yzhIRR  
} <YM!K8hu$  
/B 53Z[yL  
3,"G!0 y.  
/* w-"tA`F4  
**SiteInfoBean.java fKbg?  
*/ eemC;JV%  
package NetFox; rDWwu '  
 \4j(el  
/g>]J70  
public class SiteInfoBean { 84_Y+_9  
=B{B ?B"r  
wii.0~p  
private String sSiteURL; //Site's URL e +Ikw1y"f  
private String sFilePath; //Saved File's Path 7\AoMk}  
private String sFileName; //Saved File's Name R('\i/fy  
private int nSplitter; //Count of Splited Downloading File 6{w'q&LYcE  
Sa-" G`  
N^{}Qvrr  
public SiteInfoBean() Ou_2UT  
{//nSplitter的缺省值为5 %0zp`'3Y  
//default value of nSplitter is 5 F]L96&  
this("","","",5); 12V-EG i  
} \Ez&?yb/  
* EPJeblAV  
+V9(4la  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) pwv mb\  
{ %KPQ|^WE  
sSiteURL= sURL; GM Y[Gd  
sFilePath = sPath; !<<wI'8  
sFileName = sName; E&ReQgBft  
this.nSplitter = nSpiltter; Us\Nmso z  
?^ R"a##  
9aYVbq""  
} 5 0dx[v8  
U J uz  
iX6*OEl/Q  
public String getSSiteURL() sVH w\_F$  
{ l\TL=8u2c  
return sSiteURL; U1D;O}z~  
} d/b\:[B@  
Z6nQW53-  
ey$H2zmo  
public void setSSiteURL(String value) hG}gKs  
{ gX`C76P!  
sSiteURL = value; }((P)\s  
} (_Th4'(@Y  
N+vsQ!Qz  
dpT?*qLM  
public String getSFilePath() )K]<\Q[  
{ S rhBU6K  
return sFilePath; }%c0EY'  
} )1g\v8XT  
Y}h&dAr  
@cQ |`  
public void setSFilePath(String value) T#KVN{O  
{ HP=5 a.  
sFilePath = value; 8\+XtS  
} (S_1C,  
(rQ)0g@  
9Qq%Fw_  
public String getSFileName() D77$aCt  
{ 16"L;r  
return sFileName; aN';_tGvK  
} t'DIKug&  
\*#E4`Y  
=%{E^z>1  
public void setSFileName(String value) X=VaBy4#  
{ G{.A5{  
sFileName = value; \,G19o}`Es  
} 5N907XVu  
]_hXg*?  
JY9hD;`6y  
public int getNSplitter() 5IP@_GV|  
{ n*hRlL  
return nSplitter; ):V)Hrq?x  
} CWkAc5  
! H4uc  
OQ _wsAA  
public void setNSplitter(int nCount) _mDvRFq  
{ 8u Z4[  
nSplitter = nCount; h=_h,?_  
} HqA3.<=F,  
} r]%.,i7~8  
}9?fb[]  
EU()Nnm2  
/* 6K5KkEp  
**Utility.java w&}UgtEm  
*/ LESF*rh=  
package NetFox; cx4'rK.  
3M{b:|3/q  
_1?Fy u&<5  
public class Utility { jqy?Od )  
"#`c\JuR ]  
nb|"dK|  
public Utility() z|G 39  
{ |Vc:o_n7  
~{s7(^ P  
z(beT e  
} eC-nV)]I9  
q8vRUlf  
//线程睡眠 rVx?Yo1F'  
public static void sleep(int nSecond) :6Sb3w5h  
{ FZtILlw  
try{ ctL,Mqr\Z  
Thread.sleep(nSecond); Jx= v6==7  
} QX 393v!  
catch(Exception e) \JEI+A PY*  
{ :#p!&Fi  
e.printStackTrace (); VUGVIy.  
} -%)8=  
} AT,?dxP J  
`'<&<P  
//日志 [KjL`  
public static void log(String sMsg) }[I|oV5*+&  
{ =9vmRh? 8  
System.err.println(sMsg); REwZ41   
} g3uI1]QXLg  
jR&AQ-H&  
})}-K7v1+  
public static void log(int sMsg) sp$W=Wu7  
{ :j0r~*z-  
System.err.println(sMsg); nLjo3yvV..  
} 9}6^5f?|  
} [-Dl,P=  
tmI2BBv  
g:nU&-x#R  
/* k"2xyzt*  
**TestMethod.java SpUcrK;1  
*/ :V#W y  
package NetFox; A">A@`}  
 ,M&[c|  
MM%c   
public class TestMethod { j/xL+Y(=  
e RjpR?!\  
-3T6ck  
public TestMethod() *u%4]q  
{ ///xx/weblogic60b2_win.exe =1"8ua  
try{ L?n*b  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U8(Rye$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); hOSkxdi*^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v+|N7  
fileFetch.start(); h4^ a#%$  
} ryq95<lF  
catch(Exception e){e.printStackTrace ();} 'L2M  W  
{>c O&eiCt  
Oj*3'?<7=  
} ymBevL  
dZ7+Iw;m  
!s]LWCX+|  
public static void main(String[] args) ZAPT5  
{ r^k:$wJbRK  
new TestMethod(); [a*m9F\ ,  
} rnVh ]xJ  
} RYaf{i`  
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