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zxiaofanzxiaofan
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关闭RandomAccessFile流，美化代码
1 parent b14a498 commit 2f09a5a

1 file changed

Lines changed: 79 additions & 65 deletions

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‎src/com/zxiaofan/util/other/FileUtil.java‎

Lines changed: 79 additions & 65 deletions
Original file line numberDiff line numberDiff line change
@@ -29,8 +29,10 @@
2929
* @author zxiaofan
3030
*/
3131
public class FileUtil {
32-
static String max = "max";
3332

33+
/**
34+
* 缓存指定数据的偏移位置.
35+
*/
3436
static Map<String, Long> mapIndex = new ConcurrentHashMap<>(); // <行key,index>
3537

3638
/**
@@ -48,69 +50,75 @@ public FileUtil() {
4850
*
4951
* @param file
5052
* file
51-
* @param content
53+
* @param specialContent
5254
* 查找指定内容
5355
* @return String
5456
* @throws Exception
5557
* Exception
5658
*/
57-
@SuppressWarnings("resource")
58-
public static String getSpecificLine(File file, String content) throws Exception {
59+
public static String getSpecificLine(File file, String specialContent) throws Exception {
5960
RandomAccessFile randomAccessFile = null;
60-
randomAccessFile = new RandomAccessFile(file, "r");
61-
long fileLength = randomAccessFile.length(); // 获取当前文件的长度
62-
long indexStart = 0;
63-
if (!mapIndex.containsKey(max)) {
64-
mapIndex.put(max, 0L);
65-
}
66-
Future<String> future = null;
67-
if (mapIndex.containsKey(content)) {
68-
indexStart = mapIndex.get(content);
69-
} else {
70-
indexStart = mapIndex.get(max);
71-
// 大文件缓存全部key索引耗时较多，建议按行匹配并发,取优先完成的数据
72-
ExecutorService service = Executors.newFixedThreadPool(1);
73-
// future = service.submit(new QueryCallable(file, content));
74-
}
75-
if (indexStart > fileLength || indexStart < 0) {
76-
System.out.println("index illegal");
77-
return null;
78-
}
79-
long index = indexStart;
80-
randomAccessFile.seek(index);
81-
StringBuffer buffer = new StringBuffer();
82-
String line = null;
83-
boolean getData = false;
84-
while (index <= fileLength && null != (line = randomAccessFile.readLine())) {
85-
line = new String(line.getBytes("ISO-8859-1"), "utf-8"); // 处理乱码
86-
String key = line.substring(0, Math.min(10, line.length())); // 假设key为我们要匹配的content
87-
if (key.equals(content)) {
88-
buffer.append(line);
89-
getData = true;
90-
} else if (getData && !key.equals(content)) {
91-
break;
61+
StringBuilder builder;
62+
try {
63+
randomAccessFile = new RandomAccessFile(file, "r");
64+
long fileLength = randomAccessFile.length(); // 获取当前文件的长度
65+
long indexStart = 0;
66+
if (!mapIndex.containsKey("max")) { // 当前最大指针
67+
mapIndex.put("max", 0L);
9268
}
93-
if (!mapIndex.containsKey(key)) {
94-
mapIndex.put(key, index);
69+
Future<String> future = null;
70+
if (mapIndex.containsKey(specialContent)) {
71+
indexStart = mapIndex.get(specialContent);
72+
} else {
73+
indexStart = mapIndex.get("max");
74+
// 大文件缓存全部key索引耗时较多，建议按行匹配并发,取优先完成的数据
75+
ExecutorService service = Executors.newFixedThreadPool(1);
76+
// future = service.submit(new QueryCallable(file, content));
9577
}
96-
if (index > mapIndex.get(max)) {
97-
mapIndex.put(max, index);
78+
if (indexStart > fileLength || indexStart < 0) {
79+
System.out.println("index illegal:" + indexStart);
80+
return null;
9881
}
99-
index = randomAccessFile.getFilePointer(); // 获取下次循环的开始指针
100-
if (null != future) {
101-
try {
102-
String res = future.get(1, TimeUnit.MILLISECONDS);
103-
if (null != res) {
104-
buffer.setLength(0);
105-
buffer.append(res);
106-
break;
82+
long index = indexStart;
83+
randomAccessFile.seek(index);
84+
builder = new StringBuilder();
85+
String line = null;
86+
boolean getData = false;
87+
while (index <= fileLength && null != (line = randomAccessFile.readLine())) {
88+
line = new String(line.getBytes("ISO-8859-1"), "utf-8"); // 处理乱码
89+
String key = line.substring(0, Math.min(10, line.length())); // 假设key为我们要匹配的content
90+
if (key.equals(specialContent)) {
91+
builder.append(line);
92+
getData = true;
93+
} else if (getData && !key.equals(specialContent)) {
94+
break;
95+
}
96+
if (!mapIndex.containsKey(key)) {
97+
mapIndex.put(key, index);
98+
}
99+
if (index > mapIndex.get("max")) {
100+
mapIndex.put("max", index);
101+
}
102+
index = randomAccessFile.getFilePointer(); // 获取下次循环的开始指针
103+
if (null != future) {
104+
try {
105+
String res = future.get(1, TimeUnit.MILLISECONDS);
106+
if (null != res) {
107+
builder.setLength(0);
108+
builder.append(res);
109+
break;
110+
}
111+
} catch (Exception e) {
112+
System.out.println();
107113
}
108-
} catch (Exception e) {
109-
System.out.println();
110114
}
111115
}
116+
} finally {
117+
if (null != randomAccessFile) {
118+
randomAccessFile.close();
119+
}
112120
}
113-
return buffer.toString();
121+
return builder.toString();
114122
}
115123

116124
/**
@@ -129,12 +137,14 @@ public static String readFileToString(String fileName, String encode) throws IOE
129137
try {
130138
File file = new File(fileName);
131139
if (file.exists()) {
132-
if (file.isDirectory())
140+
if (file.isDirectory()) {
133141
throw new IOException("File '" + file + "' exists but is a directory");
134-
if (!file.canRead())
142+
}
143+
if (!file.canRead()) {
135144
throw new IOException("File '" + file + "' cannot be read");
136-
else
145+
} else {
137146
input = new FileInputStream(file);
147+
}
138148
} else {
139149
throw new FileNotFoundException("File '" + file + "' does not exist");
140150
}
@@ -145,18 +155,17 @@ public static String readFileToString(String fileName, String encode) throws IOE
145155
} else {
146156
in = new InputStreamReader(input, encode);
147157
}
148-
char buffer[] = new char[4096];
158+
char[] buffer = new char[4096];
149159
for (int n = 0; -1 != (n = in.read(buffer));) {
150160
output.write(buffer, 0, n);
151161
}
152-
String s = output.toString();
153-
return s;
162+
return output.toString();
154163
} finally {
155164
if (null != input) {
156165
try {
157166
input.close();
158167
} catch (Exception e) {
159-
System.out.print("");
168+
e.printStackTrace();
160169
}
161170
}
162171
}
@@ -178,28 +187,33 @@ public static void writeStringToFile(String fileName, String data, String encode
178187
FileOutputStream output = null;
179188
File file = new File(fileName);
180189
if (file.exists()) {
181-
if (file.isDirectory())
190+
if (file.isDirectory()) {
182191
throw new IOException("File '" + file + "' exists but is a directory");
183-
if (!file.canWrite())
192+
}
193+
if (!file.canWrite()) {
184194
throw new IOException("File '" + file + "' cannot be written to");
195+
}
185196
} else {
186197
File parent = file.getParentFile();
187-
if (parent != null && !parent.exists() && !parent.mkdirs())
198+
if (parent != null && !parent.exists() && !parent.mkdirs()) {
188199
throw new IOException("File '" + file + "' could not be created");
200+
}
189201
}
190202
try {
191203
output = new FileOutputStream(file);
192-
if (data != null)
193-
if (encode == null)
204+
if (data != null) {
205+
if (encode == null) {
194206
output.write(data.getBytes());
195-
else
207+
} else {
196208
output.write(data.getBytes(encode));
209+
}
210+
}
197211
} finally {
198212
if (null != output) {
199213
try {
200214
output.close();
201215
} catch (IOException e) {
202-
System.out.print("");
216+
e.printStackTrace();
203217
}
204218
}
205219
}

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