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try-with-resources 实例     所属分类 java
https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html


The try-with-resources statement is a try statement that declares one or more resources. 
A resource is an object that must be closed after the program is finished with it. 
The try-with-resources statement ensures that each resource is closed at the end of the statement. 
Any object that implements java.lang.AutoCloseable, 
which includes all objects which implement java.io.Closeable, can be used as a resource.



public interface AutoCloseable {
    void close() throws Exception;
}

public interface Closeable extends AutoCloseable {
    public void close() throws IOException;
}

使用 try-with-resources 

try (BufferedReader br =
                   new BufferedReader(new FileReader(path))) {
        return br.readLine();
}

使用 try finally

    BufferedReader br = new BufferedReader(new FileReader(path));
    try {
        return br.readLine();
    } finally {
        if (br != null) br.close();
    }
    
    

完整例子 public class TryResourceTest implements AutoCloseable{ private String name; private boolean error = false; public TryResourceTest(String name,boolean error){ this.name = name; this.error = error; } public static void main(String[] args) throws Exception { try(TryResourceTest test1 = new TryResourceTest("test1",false)){ test1.hello(); } System.out.println("111"); // 抛出异常 也会自动关闭 try(TryResourceTest test2 = new TryResourceTest("test2",true)){ test2.hello(); } // 这里不会运行 System.out.println("222"); } public void hello(){ if(error){ throw new RuntimeException("error,name="+name); } System.out.println("hello,name="+name); } public void close() throws Exception{ System.out.println("close run,name="+name); } }

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