Java基础 - 注解详解

@Retention(RetentionPolicy.SOURCE)
public @interface SourcePolicy {}
@Retention(RetentionPolicy.CLASS)
public @interface ClassPolicy {}
@Retention(RetentionPolicy.RUNTIME)
public @interface RuntimePolicy {}

public class RetentionTest {@SourcePolicy
public void sourcePolicy() {
}@ClassPolicy
public void classPolicy() {
}@RuntimePolicy
public void runtimePolicy() {
}
}

{
public retention.RetentionTest();
flags: ACC_PUBLIC
Code:
stack=1, locals=1, args_size=1
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: return
LineNumberTable:
line 3: 0 public void sourcePolicy();
flags: ACC_PUBLIC
Code:
stack=0, locals=1, args_size=1
0: return
LineNumberTable:
line 7: 0 public void classPolicy();
flags: ACC_PUBLIC
Code:
stack=0, locals=1, args_size=1
0: return
LineNumberTable:
line 11: 0
RuntimeInvisibleAnnotations:
0: #11() public void runtimePolicy();
flags: ACC_PUBLIC
Code:
stack=0, locals=1, args_size=1
0: return
LineNumberTable:
line 15: 0
RuntimeVisibleAnnotations:
0: #14()
}

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Target;@Documented
@Target({ElementType.TYPE,ElementType.METHOD})
public @interface TestDocAnnotation {public String value() default "default";
}

@TestInheritedAnnotation(values = {"value"}, number = 10)
public class Person {
}class Student extends Person{
@Test
public void test(){
Class clazz = Student.class;
Annotation[] annotations = clazz.getAnnotations();
for (Annotation annotation : annotations) {
System.out.println(annotation.toString());
}
}
}

public @interface Authority {
String role();
}public @interface Authorities {
Authority[] value();
}public class RepeatAnnotationUseOldVersion { @Authorities({@Authority(role="Admin"),@Authority(role="Manager")})
public void doSomeThing(){
}
}

public class HelloWorld { public void sayHello(){
System.out.println("hello....");
throw new NumberFormatException();
} public void sayWorld(){
System.out.println("world....");
} public String say(){
return "hello world!";
}}

public class HelloWorldTest extends TestCase{
private HelloWorld hw; @Override
protected void setUp() throws Exception {
super.setUp();
hw=new HelloWorld();
} //1.测试没有返回值
public void testHello(){
try {
hw.sayHello();
} catch (Exception e) {
System.out.println("发生异常.....");
} }
public void testWorld(){
hw.sayWorld();
}
//2.测试有返回值的方法
// 返回字符串
public void testSay(){
assertEquals("测试失败", hw.say(), "hello world!");
}
//返回对象
public void testObj(){
assertNull("测试对象不为空", null);
assertNotNull("测试对象为空",new String());
}
@Override
protected void tearDown() throws Exception {
super.tearDown();
hw=null;
}
}

public class HelloWorldTest {
private HelloWorld hw; @Before
public void setUp() {
hw = new HelloWorld();
} @Test(expected=NumberFormatException.class)
// 1.测试没有返回值,有别于junit3的使用，更加方便
public void testHello() {
hw.sayHello();
}
@Test
public void testWorld() {
hw.sayWorld();
} @Test
// 2.测试有返回值的方法
// 返回字符串
public void testSay() {
assertEquals("测试失败", hw.say(), "hello world!");
} @Test
// 返回对象
public void testObj() {
assertNull("测试对象不为空", null);
assertNotNull("测试对象为空", new String());
} @After
public void tearDown() throws Exception {
hw = null;
}}

@Target({ ElementType.PARAMETER, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Log {
/**
* 模块
*/
public String title() default ""; /**
* 功能
*/
public BusinessType businessType() default BusinessType.OTHER; /**
* 操作人类别
*/
public OperatorType operatorType() default OperatorType.MANAGE; /**
* 是否保存请求的参数
*/
public boolean isSaveRequestData() default true;
}

@Aspect
@Component
public class LogAspect {
private static final Logger log = LoggerFactory.getLogger(LogAspect.class); /**
* 配置织入点 - 自定义注解的包路径
*
*/
@Pointcut("@annotation(com.xxx.aspectj.lang.annotation.Log)")
public void logPointCut() {
} /**
* 处理完请求后执行
*
* @param joinPoint 切点
*/
@AfterReturning(pointcut = "logPointCut()", returning = "jsonResult")
public void doAfterReturning(JoinPoint joinPoint, Object jsonResult) {
handleLog(joinPoint, null, jsonResult);
} /**
* 拦截异常操作
*
* @param joinPoint 切点
* @param e 异常
*/
@AfterThrowing(value = "logPointCut()", throwing = "e")
public void doAfterThrowing(JoinPoint joinPoint, Exception e) {
handleLog(joinPoint, e, null);
} protected void handleLog(final JoinPoint joinPoint, final Exception e, Object jsonResult) {
try {
// 获得注解
Log controllerLog = getAnnotationLog(joinPoint);
if (controllerLog == null) {
return;
} // 获取当前的用户
User currentUser = ShiroUtils.getSysUser(); // *========数据库日志=========*//
OperLog operLog = new OperLog();
operLog.setStatus(BusinessStatus.SUCCESS.ordinal());
// 请求的地址
String ip = ShiroUtils.getIp();
operLog.setOperIp(ip);
// 返回参数
operLog.setJsonResult(JSONObject.toJSONString(jsonResult)); operLog.setOperUrl(ServletUtils.getRequest().getRequestURI());
if (currentUser != null) {
operLog.setOperName(currentUser.getLoginName());
if (StringUtils.isNotNull(currentUser.getDept())
&& StringUtils.isNotEmpty(currentUser.getDept().getDeptName())) {
operLog.setDeptName(currentUser.getDept().getDeptName());
}
} if (e != null) {
operLog.setStatus(BusinessStatus.FAIL.ordinal());
operLog.setErrorMsg(StringUtils.substring(e.getMessage(), 0, 2000));
}
// 设置方法名称
String className = joinPoint.getTarget().getClass().getName();
String methodName = joinPoint.getSignature().getName();
operLog.setMethod(className + "." + methodName + "()");
// 设置请求方式
operLog.setRequestMethod(ServletUtils.getRequest().getMethod());
// 处理设置注解上的参数
getControllerMethodDescription(controllerLog, operLog);
// 保存数据库
AsyncManager.me().execute(AsyncFactory.recordOper(operLog));
} catch (Exception exp) {
// 记录本地异常日志
log.error("==前置通知异常==");
log.error("异常信息:{}", exp.getMessage());
exp.printStackTrace();
}
} /**
* 获取注解中对方法的描述信息 用于Controller层注解
*
* @param log 日志
* @param operLog 操作日志
* @throws Exception
*/
public void getControllerMethodDescription(Log log, OperLog operLog) throws Exception {
// 设置action动作
operLog.setBusinessType(log.businessType().ordinal());
// 设置标题
operLog.setTitle(log.title());
// 设置操作人类别
operLog.setOperatorType(log.operatorType().ordinal());
// 是否需要保存request，参数和值
if (log.isSaveRequestData()) {
// 获取参数的信息，传入到数据库中。
setRequestValue(operLog);
}
} /**
* 获取请求的参数，放到log中
*
* @param operLog
* @param request
*/
private void setRequestValue(OperLog operLog) {
Map<String, String[]> map = ServletUtils.getRequest().getParameterMap();
String params = JSONObject.toJSONString(map);
operLog.setOperParam(StringUtils.substring(params, 0, 2000));
} /**
* 是否存在注解，如果存在就获取
*/
private Log getAnnotationLog(JoinPoint joinPoint) throws Exception {
Signature signature = joinPoint.getSignature();
MethodSignature methodSignature = (MethodSignature) signature;
Method method = methodSignature.getMethod(); if (method != null)
{
return method.getAnnotation(Log.class);
}
return null;
}
}

@Controller
@RequestMapping("/system/dept")
public class DeptController extends BaseController {
private String prefix = "system/dept"; @Autowired
private IDeptService deptService; /**
* 新增保存部门
*/
@Log(title = "部门管理", businessType = BusinessType.INSERT)
@RequiresPermissions("system:dept:add")
@PostMapping("/add")
@ResponseBody
public AjaxResult addSave(@Validated Dept dept) {
if (UserConstants.DEPT_NAME_NOT_UNIQUE.equals(deptService.checkDeptNameUnique(dept))) {
return error("新增部门'" + dept.getDeptName() + "'失败，部门名称已存在");
}
return toAjax(deptService.insertDept(dept));
} /**
* 保存
*/
@Log(title = "部门管理", businessType = BusinessType.UPDATE)
@RequiresPermissions("system:dept:edit")
@PostMapping("/edit")
@ResponseBody
public AjaxResult editSave(@Validated Dept dept) {
if (UserConstants.DEPT_NAME_NOT_UNIQUE.equals(deptService.checkDeptNameUnique(dept))) {
return error("修改部门'" + dept.getDeptName() + "'失败，部门名称已存在");
} else if(dept.getParentId().equals(dept.getDeptId())) {
return error("修改部门'" + dept.getDeptName() + "'失败，上级部门不能是自己");
}
return toAjax(deptService.updateDept(dept));
} /**
* 删除
*/
@Log(title = "部门管理", businessType = BusinessType.DELETE)
@RequiresPermissions("system:dept:remove")
@GetMapping("/remove/{deptId}")
@ResponseBody
public AjaxResult remove(@PathVariable("deptId") Long deptId) {
if (deptService.selectDeptCount(deptId) > 0) {
return AjaxResult.warn("存在下级部门,不允许删除");
}
if (deptService.checkDeptExistUser(deptId)) {
return AjaxResult.warn("部门存在用户,不允许删除");
}
return toAjax(deptService.deleteDeptById(deptId));
} // ...
}