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http断点续传简单实现(java)

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/* #H(|+WEu  
**SiteFileFetch.java wYhWRgP  
*/ !J[3U   
package NetFox; cU5x8[2  
import java.io.*; ~ @Ib:M  
import java.net.*; Bm%:Qc*  
xmTa$tR+  
N<:5 r  
public class SiteFileFetch extends Thread { *J?QXsg  
mUzNrkG(G  
7[QU *1bk  
SiteInfoBean siteInfoBean = null; //文件信息Bean __$IbF5  
long[] nStartPos; //开始位置 =A<kDxqH  
long[] nEndPos; //结束位置 &TSt/b/+W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -[v:1\Vv  
long nFileLength; //文件长度 O1coay  
boolean bFirst = true; //是否第一次取文件  "=H7p3  
boolean bStop = false; //停止标志 #;a 1=8H  
File tmpFile; //文件下载的临时信息 UKQ ,]VC  
DataOutputStream output; //输出到文件的输出流 f!*b8ND^R  
5SK{^hw  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ?};}#%971  
public SiteFileFetch(SiteInfoBean bean) throws IOException }+QgRGQ  
{ /]T#@>('  
siteInfoBean = bean; 31wact^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =+97VO(w]G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); NDU,9A.P  
if(tmpFile.exists ()) C+,;hj  
{ #18H Z4N  
bFirst = false; m1VyYG  
read_nPos(); `,aPK/  
} PX[taDN  
else ^M  PU?k  
{ 1okL]VrI  
nStartPos = new long[bean.getNSplitter()]; abWmPi  
nEndPos = new long[bean.getNSplitter()]; rZe"*$e  
} oGly|L>  
,y3o ,gl  
57)S"  
s7SW4ff1  
} 4kNf4l9Y  
BkJV{>?_+  
HLAWx/c,j"  
public void run() 3ZU`}  
{ \S}&QV  
//获得文件长度 &m`1lxT  
//分割文件 vML01SAi  
//实例FileSplitterFetch ,2[laJ  
//启动FileSplitterFetch线程 u1ggLH!U  
//等待子线程返回  e1S |&W8  
try{ vX)JJ|g  
if(bFirst) K-)_1  
{ q>%KIBh(  
nFileLength = getFileSize(); wtetB')yD  
if(nFileLength == -1) B=7bQli}  
{ 2JYyvJ>  
System.err.println("File Length is not known!"); /Bid:@R  
} . 3=WE@M  
else if(nFileLength == -2) y^pk)`y8  
{ RhnSQe  
System.err.println("File is not access!"); bec n$R  
} $f*N  
else ln'7kg  
{  ]P(:z  
for(int i=0;i<nStartPos.length;i++) 3) zanoYHi  
{ c7q1;X{:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %(Nu"3|$K=  
} ._~_OVU  
for(int i=0;i<nEndPos.length-1;i++) (X,Ua+{  
{ za1MSR  
nEndPos = nStartPos[i+1]; *|Q'?ty(x  
} e4yd n  
nEndPos[nEndPos.length-1] = nFileLength; x$J1%K*  
} 2+TCFpv  
} *.r i8  
X7?p$!M6;B  
9loWh5_1Z  
//启动子线程 U GQ{QH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {%9)l,  
for(int i=0;i<nStartPos.length;i++) \ZigG{  
{ S WVeUL#5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =2\k Jv3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nY'0*:'u  
nStartPos,nEndPos,i); tjBs>w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rC14X}X6  
fileSplitterFetch.start(); \$/)o1SG  
} x:88E78  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7;#9\a:R?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {x W? v;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q$Ga.fI  
nEndPos = " + nFileLength); JWr:/?  
// fileSplitterFetch[nPos.length-1].start(); bA@!0,m  
G6w&C^J*8>  
f/~"_O%  
//等待子线程结束 YxlV2hcX;  
//int count = 0; EQSOEf[  
//是否结束while循环 ,@tkL!"9q  
boolean breakWhile = false; 5:Pp62  
<h4"^9hL  
$]%;u: Sa  
while(!bStop) /WRS6n  
{ 2BXpk^d5y  
write_nPos(); r )ZUeHt}w  
Utility.sleep(500); }Xr-xh \v  
breakWhile = true; w0)V3  
4[ M!x  
{2vk<  
for(int i=0;i<nStartPos.length;i++) lTv I;zy  
{ 6b~Zv$5^Y-  
if(!fileSplitterFetch.bDownOver) ]{{A/ j\  
{ N#Y%+1  
breakWhile = false; h=.|!u  
break; nW3-)Q89  
} yMq&9R9F  
} UQ:H3  
if(breakWhile) ;o8C(5xE|  
break; NKvBNf|D  
dFS>uIT7X  
+(x^5~QX  
//count++; O%H_._#N`  
//if(count>4) l9lBhltOH  
// siteStop(); MIo<sJuv  
} x9Fga_  
g34<0%6jd  
K]Q#B|_T  
System.err.println("文件下载结束!"); l~;H~h!h/  
} 4*}[h9J}\  
catch(Exception e){e.printStackTrace ();} l Q]&:%^\  
} rmu5K$pl  
p @&>{hi@  
!Y>lAxd  
//获得文件长度 S_/9eI~X  
public long getFileSize() <`i " 5`J  
{ 15+>W4v  
int nFileLength = -1; |!E>I  
try{ -=iGl5P?  
URL url = new URL(siteInfoBean.getSSiteURL()); "~(qp_AI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z8_m<uewz  
httpConnection.setRequestProperty("User-Agent","NetFox"); ns[v.YDL  
{a\O7$A\F  
5ppOG_  
int responseCode=httpConnection.getResponseCode(); 'MRvH lCM  
if(responseCode>=400) (9% ki$=}+  
{ bXF>{%(}E  
processErrorCode(responseCode); Oi AZA<  
return -2; //-2 represent access is error -$**/~0zU  
} @X4Ur+d  
a yn6k=F  
V>ML-s9  
String sHeader; L^bt-QbhO  
7K,Quq.%+  
:K>v F`SM  
for(int i=1;;i++) 3sIW4Cs7)U  
{ MGze IrV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 59!yz'feF  
//Utility.log(in.readLine()); t ~ruP',~\  
sHeader=httpConnection.getHeaderFieldKey(i); $}V<U m  
if(sHeader!=null) zI$^yk-vn  
{ &E0L7?l  
if(sHeader.equals("Content-Length")) 6E/>]3~!  
{ wwrP7T+d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dE19_KPm[j  
break; "[2CV!_  
} l*>t@:2J  
} 'KB\K)cD=3  
else 6w(Mb~[n  
break; +KgoLa  
} ZUP\)[~  
} M #'br<]  
catch(IOException e){e.printStackTrace ();} '?=SnjMX  
catch(Exception e){e.printStackTrace ();} L9Sd4L_e  
QEKSbxL\W  
&IsQgS7R  
Utility.log(nFileLength); RO[Ko-m|/N  
Ls{z5*<FM  
qX{"R.d  
return nFileLength; %E#OUo[y/  
} VN[C%C  
,Tc3koi  
Lh3>xZy"-z  
//保存下载信息(文件指针位置) `Fa49B|`D  
private void write_nPos() x2x) y08  
{ cKuU#&FaV  
try{ ?T=] ?[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !+T\}1f7d  
output.writeInt(nStartPos.length); OLh`R]Sd  
for(int i=0;i<nStartPos.length;i++) x{{QS$6v  
{ !$Aijd s5  
// output.writeLong(nPos); ]T|9>o!  
output.writeLong(fileSplitterFetch.nStartPos); Ot}fGiio  
output.writeLong(fileSplitterFetch.nEndPos); )OQhtxK  
} WeDeD\zy  
output.close(); h07Z.q ;  
} L1=3_fO  
catch(IOException e){e.printStackTrace ();} K*iy^}  
catch(Exception e){e.printStackTrace ();} ,<?iL~> %  
} d\aKGq;8C  
Q|QVm,m  
?#; oqH<  
//读取保存的下载信息(文件指针位置) = ms(dr^n  
private void read_nPos() Rs_0xh  
{ f ?8cO#GU  
try{ Ww5c9orXn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6BM[RL?T  
int nCount = input.readInt(); [ []'U'  
nStartPos = new long[nCount]; 0^'A^  
nEndPos = new long[nCount]; MV +R$  
for(int i=0;i<nStartPos.length;i++) ^kZfE"iE2  
{ "<o[X ?u  
nStartPos = input.readLong(); M S 3?#b  
nEndPos = input.readLong(); x g=}MoX  
} 2VmQ%y6e"  
input.close(); - s[=$pDU  
} piYv }4;:(  
catch(IOException e){e.printStackTrace ();} vSty.:bY\p  
catch(Exception e){e.printStackTrace ();} X"WKgC g$  
} T=r-6eN  
/2}o:vLj  
1HQh%dZZ  
private void processErrorCode(int nErrorCode) ?#8',:  
{ O@JgVdgf  
System.err.println("Error Code : " + nErrorCode); Y g>W.wA  
} gXr"],OM;  
@3`:aWda  
~RcI+jR)  
//停止文件下载 5/x"!Jk  
public void siteStop() b3(pRg[Fp  
{ BiGB<Jr  
bStop = true; Q'-V\G)11  
for(int i=0;i<nStartPos.length;i++) VBc[(8o  
fileSplitterFetch.splitterStop(); eduaG,+k7p  
O7@CAr  
Eu/~4:XN  
} u I$| M  
} \zj _6Os  
//负责部分文件的抓取 s_]p6M  
**FileSplitterFetch.java /H#- \r&r  
*/  2|'v[  
package NetFox; WrK!]17or  
rZRcy9$y>  
NGYliP,.6  
import java.io.*; 5dffF e  
import java.net.*; ]zp5 6U|xa  
u\YH,  
 V|=PaO  
public class FileSplitterFetch extends Thread { _XT],"  
'[#a-8-JY_  
tX;00g;U.  
String sURL; //File URL 4d&#NP  
long nStartPos; //File Snippet Start Position o(xRq;i  
long nEndPos; //File Snippet End Position #_yQv?J  
int nThreadID; //Thread's ID r fqw/o  
boolean bDownOver = false; //Downing is over Gvo(iOU  
boolean bStop = false; //Stop identical @$FE}j_  
FileAccessI fileAccessI = null; //File Access interface |1^>n,C  
3wXmX  
>Gbj1>C}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EtN@ 6xP  
{ bc}X.IC  
this.sURL = sURL; 5,=Yi$x  
this.nStartPos = nStart; TR!^wB<F  
this.nEndPos = nEnd; 1);$#Dlt k  
nThreadID = id; RZ)sCR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B5J!&suX  
} mhnjY K9  
PfX{n5yBW8  
8@%Xd^  
public void run() [% chN /  
{ [c4.E"  
while(nStartPos < nEndPos && !bStop) ;9r Z{'i+|  
{ QX (x6y>Q  
:T~Aa(%(  
/UeLf $%ZW  
try{ `x:znp}'  
URL url = new URL(sURL); qh Ezv~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A^7!:^%K  
httpConnection.setRequestProperty("User-Agent","NetFox"); YArNJ5z=  
String sProperty = "bytes="+nStartPos+"-"; 1|Y(XB^os(  
httpConnection.setRequestProperty("RANGE",sProperty); w+Ve T@  
Utility.log(sProperty); 8+vZ9!7  
?]gZg[  
@C)O[&Sk  
InputStream input = httpConnection.getInputStream(); lhg3 }dW  
//logResponseHead(httpConnection); Li ,B,   
E_&Hje|J_[  
1lyJ;6i6L  
byte[] b = new byte[1024]; ^q6H =Dl  
int nRead; b ABx' E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fs4pAB#F  
{ Hh @q;0ni  
nStartPos += fileAccessI.write(b,0,nRead); Mr'}IX5  
//if(nThreadID == 1) M,V+bt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BqZ^I eC$  
} #QJ  mAA  
Z:f0>  
Z&8 7Aj  
Utility.log("Thread " + nThreadID + " is over!"); Vzy]N6QT{  
bDownOver = true; ?7-#iC`  
//nPos = fileAccessI.write (b,0,nRead); 7}bjJR "  
} ];Whvdnv  
catch(Exception e){e.printStackTrace ();} lJ]r %YlF  
} !f_GR Pj'  
} P# 2&?.d\  
zi:F/TlUC  
bb;fV  
//打印回应的头信息 mY-Z$8r  
public void logResponseHead(HttpURLConnection con) KtJE  
{ ZWMX!>o<  
for(int i=1;;i++) WrbDB-uM  
{ J#Fe"  
String header=con.getHeaderFieldKey(i); 8 o8FL~&]  
if(header!=null) m^ zx &  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m}.ru)^p  
Utility.log(header+" : "+con.getHeaderField(header)); Hxr2Q]c?u  
else WO*yJ`9]  
break; I Vy,A7f  
} Bc}<B:q%b  
} `7jm   
7'FDI`e[  
X:-X3mV9{  
public void splitterStop() :NU-C!eT  
{ vy/U""w`  
bStop = true; RBx`<iBe  
} TI}H(XL(  
 .Pq8C  
qx 3.oU  
} k/l@P  
4,9AoK)yp  
=f@O~nGm  
/* tYIHsm\b  
**FileAccess.java #%VprcEK  
*//文件访问(定位,写) T Uhp  
package NetFox; (Br$(XJoK}  
import java.io.*; `.;7O27A^%  
cb&y8!ci~  
uuj"Er31  
public class FileAccessI implements Serializable{ gT @YG;  
IcL3.(!]l  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d;S:<]l'  
RandomAccessFile oSavedFile; ->wY|7  
long nPos; ;]fpdu{  
hgj#VY$B  
j>&n5?  
public FileAccessI() throws IOException 567ot|cc  
{ 5!#"8|oY  
this("",0); el!Bi>b9c!  
} w|WZEu:0|  
^a; V-US  
V$ 38  
public FileAccessI(String sName,long nPos) throws IOException /iif@5lw{  
{ +Smv<^bW  
oSavedFile = new RandomAccessFile(sName,"rw"); |}Mkn4  
this.nPos = nPos; sxL;o >{  
oSavedFile.seek(nPos); ]wne2WXE  
} mXc/sh")X  
N=D Ynz_~  
4:r^6m%%  
public synchronized int write(byte[] b,int nStart,int nLen) QXJD' c  
{ ZC"6B(d  
int n = -1; |L;'In  
try{ R $'}Z  
oSavedFile.write(b,nStart,nLen); 3FPy"[[  
n = nLen; &Wd,l$P<O  
} 2?t(%uf]  
catch(IOException e) NJqALm!(  
{ (m;P,*  
e.printStackTrace (); !qrF=a  
} 4NR,"l)  
miS+MK"  
{J})f>x<xM  
return n; %>I!mD"X\  
} !P@u4FCs  
QX%m4K/a  
<eN>X:_N  
} TG?;o/  
?P`wLS^;  
5[l3]HOO  
/* 1+eC'&@Xjt  
**SiteInfoBean.java -D:J$d 6R<  
*/ W}L =JJo},  
package NetFox; eE7 R d>  
jLr8?Hyf  
4L!{U@ '  
public class SiteInfoBean { IUd>jHp`6  
ItM?nyA  
c09] Cp<  
private String sSiteURL; //Site's URL { w!}:8p  
private String sFilePath; //Saved File's Path b@YSrjJ  
private String sFileName; //Saved File's Name @1n0<V /  
private int nSplitter; //Count of Splited Downloading File VPN@q<BV  
7/Lbs  
czMLvPXRx  
public SiteInfoBean() bSz6O/A/  
{//nSplitter的缺省值为5 LV8,nTYvE  
//default value of nSplitter is 5 d,<ctd  
this("","","",5); 9q* sR1  
} Br#]FB|tD  
] {NY;|&I'  
,6t0w|@-k  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) aF'Ik XG d  
{ g?=B{V  
sSiteURL= sURL; }d.R=A9L  
sFilePath = sPath; $,i:#KT`  
sFileName = sName; K:'pK1zy  
this.nSplitter = nSpiltter; FC]? T  
A1Q]KS@  
2#+@bk>^{  
} xmiF!R  
R63"j\0  
Y}1|/6eJ  
public String getSSiteURL() &OI=r vDmo  
{ .\U+`>4av  
return sSiteURL; ZLL0 6p   
} Nq*\{rb  
0w+hf3K+:  
c"O\fX  
public void setSSiteURL(String value) L7D'wf  
{ g"T~)SQP  
sSiteURL = value; 2Y wV}  
} 5j ]}/Aq  
{xM%3  
~]"}s(J;  
public String getSFilePath() Q;5\( 0w5  
{ $oxPmELtpe  
return sFilePath; W:5m8aE\  
} vO0ql  
R1P,0Yf  
WO)K*c1F  
public void setSFilePath(String value) gVG :z_6  
{ "r"Y9KODm  
sFilePath = value; ^kt"n( P5  
} v11mu2  
H[>_LYZ8  
}Bc6:a  
public String getSFileName() -CL7^  
{ '|FM|0~-J  
return sFileName; c7iu[vE'+  
} J=\Y4- "  
E0)v;yRcw  
ie$=3nZJ}  
public void setSFileName(String value) ~!:F'}bj  
{ m2_&rjGz  
sFileName = value; ^1Yx'ua'  
} JWn9&WK  
;Rnb^t6Z  
'|]zBpz  
public int getNSplitter() |fw+{f  
{ {Or|] 0  
return nSplitter; ,/d-o;W  
} Z&.FJZUP  
Zb9@U: \  
}(hE{((o  
public void setNSplitter(int nCount) MnX2sX|  
{ z4f5@  
nSplitter = nCount; Y^6=_^  
} t: [[5];E  
} XD|&{/O  
DG:=E/@  
:\bttPw5  
/* VWMCbg>R  
**Utility.java LZoth+:  
*/ x%(!+  
package NetFox; hVGakp9WE  
ho(Y?'^t3  
_OrE{  
public class Utility { Y/$SriC_+'  
-Z;:_"&9  
Jhj]rsGk  
public Utility() H/L3w|2+  
{ Z2$-},i  
[j![R  
<v2R6cj5  
} \\/X+4|o'  
-_314j=`/  
//线程睡眠 [ 0~qs|27  
public static void sleep(int nSecond) >K &b,o,[  
{ '.dW>7  
try{ t 1&p> v  
Thread.sleep(nSecond); ar^`r!ABEh  
} $K,aLcu  
catch(Exception e) f a\cLC  
{ lhjPS!A~  
e.printStackTrace (); |QzPY8B9O  
} nB:Bw8U"Q  
} de`6%%|  
mWGT (`|~/  
//日志 Awr]@%I  
public static void log(String sMsg) 5S7Z]DXiT8  
{ Hv`Zc*  
System.err.println(sMsg); M0"feq  
} lO) B/N&  
m# SZI}  
~]yqJYiid^  
public static void log(int sMsg) my} P\r.  
{ L`Ic0}|lzy  
System.err.println(sMsg); 3{_+dE"9  
} G6J3F  
} ILVbbC`D  
.6'T;SoK>  
J`V6zGgW  
/* 1U9iNki  
**TestMethod.java UG!&n@R  
*/ Mr1pRIYMd  
package NetFox; :5Vu.\,1  
s e1ipn_A  
xj~6,;83xR  
public class TestMethod { WkO .  
I3L1|!  
x[?_F  
public TestMethod() stDn{x .  
{ ///xx/weblogic60b2_win.exe ::5-UxGL<2  
try{ P#0 _  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FE5R ^W#u-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y%GV9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D{4 Y:O&J  
fileFetch.start(); e-s@@k  
} Vnl~AQfk|  
catch(Exception e){e.printStackTrace ();} #2MwmIeA  
O7K))w  
vd ;wQ  
} IR>K ka(B  
"E8!{  
LNg1q1 P3  
public static void main(String[] args) K)14v;@  
{ <AIsNqr  
new TestMethod(); F0!r9U((  
} NMDNls&)k  
} O]Hg4">f  
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