java_IO_1

public class DirStudy {
    public static void main(String[] args) {
        File file = new File("F:/EclipseWorkspace/Java300/temp/test");
        //mkdir 父目录中又不存在的就创建失败  若已存在也创建失败  
        boolean flag = file.mkdir();
        System.out.println(flag);
        //mkdirs 会将文件链中不存在的目录都拿创建  推荐使用mkdirs
        flag = file.mkdirs();
        System.out.println(flag);
    }
}

---

false
true

File file = new File("F:/EclipseWorkspace/Java300");
        //返回该目录下的文件或目录的字符串名称  只返回一层
        String[] subString  = file.list();
        for(String temp:subString) {
            System.out.println(temp);
        }
        
        File[] subFile  = file.listFiles();
        for(File temp:subFile) {
            System.out.println(temp.getPath());
        }

---

.classpath
.project
.settings
bin
src
temp
F:EclipseWorkspaceJava300.classpath
F:EclipseWorkspaceJava300.project
F:EclipseWorkspaceJava300.settings
F:EclipseWorkspaceJava300in
F:EclipseWorkspaceJava300src
F:EclipseWorkspaceJava300 emp

---

递归打印目录下所有内容：

public static void printPath(File file, int deep) {
        for (int i = 0; i < deep; i++) {
            System.out.print("-");
        }
        System.out.println(file.getAbsolutePath());
        if (file == null || !file.exists()) {
            return;
        } else if (file.isDirectory()) {
            File[] temp = file.listFiles();
            for (File t : temp) {
                printPath(t, deep + 1);
            }
        }
    }

输出：

F:EclipseWorkspaceJava300
-F:EclipseWorkspaceJava300.classpath
-F:EclipseWorkspaceJava300.project
-F:EclipseWorkspaceJava300.settings
--F:EclipseWorkspaceJava300.settingsorg.eclipse.jdt.core.prefs
-F:EclipseWorkspaceJava300in
--F:EclipseWorkspaceJava300inioStudy
---F:EclipseWorkspaceJava300inioStudyDirStudy.class
---F:EclipseWorkspaceJava300inioStudyIOstudy1.class
--F:EclipseWorkspaceJava300in	est
---F:EclipseWorkspaceJava300in	eststringTest
----F:EclipseWorkspaceJava300in	eststringTestArrayCopy1.class
----F:EclipseWorkspaceJava300in	eststringTestMyArrayList.class
----F:EclipseWorkspaceJava300in	eststringTestMyHashMap.class
----F:EclipseWorkspaceJava300in	eststringTestNode.class
----F:EclipseWorkspaceJava300in	eststringTestTestBubbleSort.class
----F:EclipseWorkspaceJava300in	eststringTestTestCollection.class
----F:EclipseWorkspaceJava300in	eststringTestTestString.class
-F:EclipseWorkspaceJava300src
--F:EclipseWorkspaceJava300srcioStudy
---F:EclipseWorkspaceJava300srcioStudyDirStudy.java
---F:EclipseWorkspaceJava300srcioStudyIOstudy1.java
--F:EclipseWorkspaceJava300src	est
---F:EclipseWorkspaceJava300src	eststringTest
----F:EclipseWorkspaceJava300src	eststringTestArrayCopy1.java
----F:EclipseWorkspaceJava300src	eststringTestMyArrayList.java
----F:EclipseWorkspaceJava300src	eststringTestMyHashMap.java
----F:EclipseWorkspaceJava300src	eststringTestTestBubbleSort.java
----F:EclipseWorkspaceJava300src	eststringTestTestCollection.java
----F:EclipseWorkspaceJava300src	eststringTestTestString.java
-F:EclipseWorkspaceJava300	emp
--F:EclipseWorkspaceJava300	emp	est

---

字节到字符是解码（decode），字符到字节是编码（encode）。