字符串基础Strings="HelloWorld!";s.chars().mapToObj(letter->(char)letter).map(Character::toUpperCase).forEach(System.out::print);//输出你好世界！StringBuffer是同步的，StringBuilder不是同步的，所以StringBuilder执行得更快取文件并输出找到的第一个Spring行.xml"))){Streamstream=bf.lines();stream.filter(line->line.contains("Spring")).findFirst().ifPresent(System.out::println);}catch(Exceptione){}//输出SpringBoot演示项目另一种读取路径的方法(路径)){stream.filter(line->line.contains("Spring")).findFirst()。ifPresent(System.out::println);}catch(Exceptione){}//输出SpringBoot演示项目读取文件目录Files.listPathpath=Paths.get("/Users","/username/Documents/git_code/course/");try(Streamstream=Files.list(path)){stream.filter(p->p.toFile().isDirectory()).forEach(System.out::println);}catch(Exceptione){}//输出/Users/username/Documents/git_code/course/target/Users/username/Documents/git_code/course/.mvn/Users/username/Documents/git_code/course/.idea/Users/username/Documents/git_code/course/src遍历文件目录Files.walkPathpath=Paths.get("/Users","/username/Documents/git_code/course/");try(Streamstream=Files.walk(path)){stream.filter(p->p.toFile().isDirectory()).forEach(System.out::println);}catch(Exceptione){}//输出/Users/用户名/Documents/git_code/course/Users/用户名/Documents/git_code/course/target/Users/用户名/Documents/git_code/course/target/generated-sources/Users/username/Documents/git_code/course/target/generated-sources/annotations/Users/用户名/Documents/git_code/course/target/classes/Users/username/Documents/git_code/course/target/classes/static/Users/用户名/Documents/git_code/course/target/classes/templates/Users/username/Documents/git_code/course/target/classes/templates/pdf/Users/username/Documents/git_code/course/.mvn/Users/username/Documents/git_code/course/.mvn/wrapper/Users/username/Documents/git_code/course/.idea/Users/username/Documents/git_code/course/.idea/libraries/Users/username/Documents/git_code/course/src遍历指定层次目录Files.walkPathpath=Paths.get("/Users","/username/Documents/git_code/course/");try(Streamstream=Files.walk(path,2)){stream.filter(p->p.toFile().isDirectory()).forEach(System.out::println);}catch(Exceptione){}//输出/Users/username/Documents/git_code/课程/用户/用户名/文档/git_code/课程/目标/用户/username/Documents/git_code/course/target/generated-sources/Users/username/Documents/git_code/course/target/classes/Users/username/Documents/git_code/course/.mvn/Users/username/Documents/git_code/course/.mvn/wrapper/Users/username/Documents/git_code/course/.idea/Users/username/Documents/git_code/course/.idea/libraries/Users/username/Documents/git_code/course/src/Users/username/文档/git_code/course/src/test/Users/用户名/Documents/git_code/course/src/main
