1.作用
通过写java代码，实现自己想要定义的命令，并且也可以实现按Tab键命令补全，help命令功能，退出程序功能。
2.需要的jar包
jar包名 | 说明 |
jline-3.6.2.jar | 提供命令行开发需要的类和方法(核心jar包) |
因为在windows上需要用到系统的dll文件（动态链接库），所以还需要下面五个jar包:
jar包名 | 说明 |
jansi-1.17.jar | Jansi是一个用于生成和解释ANSI转义序列的java库 |
jna-4.2.2.jar | Java本机访问 |
jsr305-3.0.2.jar | Findbugs的JSR305注释 |
juniversalchardet-1.0.3.jar | Java编码检测器库 |
sshd-core-1.4.0.jar |
3.搭建一个最基础的框架
(1)计算机上的虚拟终端
Terminal terminal = TerminalBuilder.builder().system(true).build();代码 | 说明 |
TerminalBuilder | TerminalBuilder类，创建终端的生成器类 |
.builder() | 返回new TerminalBuilder() |
.system(true) | 给TerminalBuilder类中的system赋值并返回TerminalBuilder类 |
.build() | 调用TerminalBuilder类中的build()方法获取Terminal 并返回Terminal |
(2)通过输入从控制台读取行
LineReader lineReader = LineReaderBuilder.builder().terminal(terminal).build();代码 | 说明 |
LineReaderBuilder | LineReaderBuilder 类 |
.builder() | 返回new LineReaderBuilder () |
.terminal(terminal) | 给LineReaderBuilder 类中的terminal赋值并返回LineReaderBuilder 类 |
.build() | 返回LineReader |
(3)原样输出输入的内容的demo
public static void main(String[] args) {
try {
Terminal terminal = TerminalBuilder.builder().system(true).build();
LineReader lineReader = LineReaderBuilder.builder().terminal(terminal).build();
String prompt = "demo > "; // 输入命令提示信息
// 用while死循环，可以在执行完命令后不退出程序，可以继续输入命令
while (true) {
String line = lineReader.readLine(prompt); // 获取输入的信息
System.out.println("输入的命令是：" + line); // 输出输入的信息
}
} catch (Exception e) {
e.printStackTrace();
}
}执行结果如下：
demo > a
输入的命令是：a
demo > b
输入的命令是：b
demo >4.执行命令
把输入的命令解析成的list传进需要执行命令的方法中，逐个取值，通过switch判断需要执行哪个方法，依次执行。
public static void main(String[] args) {
try {
Terminal terminal = TerminalBuilder.builder().system(true).build();
LineReader lineReader = LineReaderBuilder.builder().terminal(terminal).build();
String prompt = "demo > ";
while (true) {
String line = lineReader.readLine(prompt);
System.out.println("输入的命令是：" + line);
if (null == line) {
continue;
}
line = line.trim();
if (!line.isEmpty()) {
ParsedLine parsedLine = lineReader.getParsedLine(); // 解析输入的命令
if (null == parsedLine) {
continue;
}
List<String> words = parsedLine.words(); // 获取输入的命令解析成的list
System.out.println("解析命令生成的list为：" + words);
Demo.executeCommand(words); // 执行命令
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void executeCommand(List<String> commands) throws Exception {
switch (commands.get(0)) {
case "schema":
if (commands.size() >= 2) {
Demo.schemaCommand(commands);
} else {
System.out.println("schema命令");
}
break;
case "table":
if (commands.size() >= 2) {
Demo.tableCommand(commands);
} else {
System.out.println("table命令");
}
break;
case "help":
System.out.println("帮助");
break;
case "quit":
System.out.println("退出程序");
System.exit(0);
break;
default:
System.out.println("不支持该命令");
}
}
public static void schemaCommand(List<String> commands) throws Exception {
switch (commands.get(1)) {
case "select":
System.out.println("查询schema");
break;
case "update":
System.out.println("修改schema");
break;
default:
System.out.println("不支持该命令");
}
}
public static void tableCommand(List<String> commands) throws Exception {
switch (commands.get(1)) {
case "select":
System.out.println("查询表");
break;
case "update":
System.out.println("修改表");
break;
default:
System.out.println("不支持该命令");
}
}执行结果如下：
demo > schema select
输入的命令是：schema select
解析命令生成的list为：[schema, select]
查询schema
demo > schema update
输入的命令是：schema update
解析命令生成的list为：[schema, update]
修改schema
demo > table select
输入的命令是：table select
解析命令生成的list为：[table, select]
查询表
demo > help
输入的命令是：help
解析命令生成的list为：[help]
帮助
demo > quit
输入的命令是：quit
解析命令生成的list为：[quit]
退出程序5.help命令
把所有命令放到list里面，执行help命令时，输出list中的内容
public static void executeCommand(List<String> commands) throws Exception {
switch (commands.get(0)) {
case "schema":
if (commands.size() >= 2) {
Demo.schemaCommand(commands);
} else {
System.out.println("schema命令");
}
break;
case "table":
if (commands.size() >= 2) {
Demo.tableCommand(commands);
} else {
System.out.println("table命令");
}
break;
case "help":
System.out.println("帮助");
List<Command> commandList = getCommandList();
for (int i = 0; i < commandList.size(); i++) {
System.out.print(commandList.get(i).getCommand());
System.out.println(commandList.get(i).getDescription());
List<Command> childCommandList = commandList.get(i).getChildCommandList();
if (null != childCommandList) {
for (int j = 0; j < childCommandList.size(); j++) {
System.out.print(" " + childCommandList.get(j).getCommand());
System.out.println(childCommandList.get(j).getDescription());
}
}
}
break;
case "quit":
System.out.println("退出程序");
System.exit(0);
break;
default:
System.out.println("不支持该命令");
}
}
public static List<Command> getCommandList() throws Exception {
List<Command> commandList = new ArrayList<Command>();
List<Command> schemaCommandList = new ArrayList<Command>();
schemaCommandList.add(new Command("select", "查询模式", null));
schemaCommandList.add(new Command("update", "修改模式", null));
commandList.add(new Command("schema", "操作模式", schemaCommandList));
List<Command> tableCommandList = new ArrayList<Command>();
tableCommandList.add(new Command("select", "查询表", null));
tableCommandList.add(new Command("update", "修改表", null));
commandList.add(new Command("table", "操作表", tableCommandList));
commandList.add(new Command("help", "帮助", null));
commandList.add(new Command("quit", "退出程序", null));
return commandList;
}Command对象类
public class Command {
private String command;
private String description;
private List<Command> childCommandList;
public String getCommand() {
return command;
}
public void setCommand(String command) {
this.command = command;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public List<Command> getChildCommandList() {
return childCommandList;
}
public void setChildCommandList(List<Command> childCommandList) {
this.childCommandList = childCommandList;
}
public Command(String command, String description, List<Command> childCommandList) {
this.command = command;
this.description = description;
this.childCommandList = childCommandList;
}
}执行结果如下：
demo > help
输入的命令是：help
解析命令生成的list为：[help]
帮助
schema操作模式
select查询模式
update修改模式
table操作表
select查询表
update修改表
help帮助
quit退出程序
demo > quit
输入的命令是：quit
解析命令生成的list为：[quit]
退出程序6.Tab命令补全
tab命令补全只需要在初始化LineReader类的时候添加上即可。
由原来的
LineReader lineReader = LineReaderBuilder.builder().terminal(terminal).build();改为
LineReader lineReader = LineReaderBuilder.builder().terminal(terminal).completer(Demo.getCompleter()).build();getCompleter()方法相关代码如下：
private static Completer getCompleter() {
Completer completer = new AggregateCompleter(
getSchemaCompleter(),
getTableCompleter(),
getHelpCompleter(),
getQuitCompleter()
);
return completer;
}
private static Completer getSchemaCompleter() {
Completer schemaCompleter = new TreeCompleter(
node("schema",
node("select", node(NullCompleter.INSTANCE)),
node("update", node(NullCompleter.INSTANCE))
)
);
return schemaCompleter;
}
private static Completer getTableCompleter() {
Completer tableCompleter = new TreeCompleter(
node("table",
node("select", node(NullCompleter.INSTANCE)),
node("update", node(NullCompleter.INSTANCE))
)
);
return tableCompleter;
}
private static Completer getHelpCompleter() {
return new ArgumentCompleter(new StringsCompleter("help"), NullCompleter.INSTANCE);
}
private static Completer getQuitCompleter() {
return new ArgumentCompleter(new StringsCompleter("quit"), NullCompleter.INSTANCE);
}- StringsCompleter 只能实现一个单词的补全
- ArgumentCompleter 补全整条命令
- AggregateCompleter将多种可能的补全方式组合到一起
- TreeCompleter是树形的集合，node添加子命令
- ArgumentCompleter 相当于串联电路，而 AggregateCompleter 相当于并联电路
7.输入密码不显示但能获取到密码(ReadPassword)
java.io.Console类可以不回显输入的密码
我用的eclipse，因为eclipse没有主控制台console，所以取不到console，System.console()只能是null
程序打包之后是可以正常用的
public static void main(String[] args) {
Console console = System.console();
if (console != null) {
String name = console.readLine("input name: ");
char[] password = console.readPassword("input password: ");
String pwd = new String(password);
System.out.println("name = " + name + " password = " + pwd);
}
}执行结果如下：
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