Java: Using Lambda expressions to simplify code example: lambda expressions

Java: Using Lambda expressions to simplify code example: lambda expressions

Previously, the 3rd-party service was called, and every method was almost "long". It was too cool to write, and it was easy to modify and leak.

public void authorizeRoleToUser(Long userId, List<Long> roleIds) {    try {        power.authorizeRoleToUser(userId, roleIds);    } catch (MotanCustomException ex) {        if (ex.getCode().equals(MSUserException.notLogin().getCode()))            throw UserException.notLogin();        if (ex.getCode().equals(MSPowerException.haveNoPower().getCode()))            throw PowerException.haveNoPower();        throw ex;    } catch (MotanServiceException ex) {        CatHelper.logEventService("Power-authorizeRoleToUser", "authorizeRoleToUser", ex.getStatus(),                ex.getErrorCode(), ex.getMessage());        throw ex;    } catch (MotanAbstractException ex) {        CatHelper.logEventService("Power-authorizeRoleToUser", "authorizeRoleToUser", ex.getStatus(),                ex.getErrorCode(), ex.getMessage());        throw ex;    } catch (Exception ex) {        CatHelper.logError(ex);        throw ex;    }}

After learning and extracting encapsulation, I extracted try... catch... to the public and obtained these two methods:

import java.util.function.Supplier;public static <T> T tryCatch(Supplier<T> supplier, String serviceName, String methodName) {    try {        return supplier.get();    } catch (MotanCustomException ex) {        if (ex.getCode().equals(MSUserException.notLogin().getCode()))            throw UserException.notLogin();        if (ex.getCode().equals(MSPowerException.haveNoPower().getCode()))            throw PowerException.haveNoPower();        throw ex;    } catch (MotanServiceException ex) {        CatHelper.logEventService(serviceName + "-" + methodName, methodName, ex.getStatus(), ex.getErrorCode(),                ex.getMessage());        throw ex;    } catch (MotanAbstractException ex) {        CatHelper.logEventService(serviceName + "-" + methodName, methodName, ex.getStatus(), ex.getErrorCode(),                ex.getMessage());        throw ex;    } catch (Exception ex) {        CatHelper.logError(ex);        throw ex;    }}public static void tryCatch(Runnable runnable, String serviceName, String methodName) {    tryCatch(() -> {        runnable.run();        return null;    }, serviceName, methodName);}

It is so simple to use now. For example:

public void authorizeRoleToUser(Long userId, List<Long> roleIds) {    tryCatch(() -> { power.authorizeRoleToUser(userId, roleIds); }, "Power", "authorizeRoleToUser");}

There is also a returned value:

public List<RoleDTO> listRoleByUser(Long userId) {    return tryCatch(() -> power.listRoleByUser(userId), "Power", "listRoleByUser");}

This is my first Java article. There are both surprises and disappointments in learning Java. We will continue to share our experiences in the future.