《Pro Spring Boot 2》第四章：Web Applications with Spring Boot

package com.apress.todo.domain;


import lombok.Data;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import java.time.LocalDateTime;
import java.util.UUID;

@Data
public class ToDo {

    @NotNull
    private String id;
    @NotNull
    @NotBlank
    private String description;
    private LocalDateTime created;
    private LocalDateTime modified;
    private boolean completed;

    public ToDo(){
        LocalDateTime date = LocalDateTime.now();
        this.id = UUID.randomUUID().toString();
        this.created = date;
        this.modified = date;
    }

    public ToDo(String description){
        this();
        this.description = description;
    }
}

package com.apress.todo.repository;

import com.apress.todo.domain.ToDo;
import org.springframework.stereotype.Repository;

import java.time.LocalDateTime;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Collectors;

@Repository
public class ToDoRepository implements CommonRepository<ToDo> {

    private Map<String,ToDo> toDos = new HashMap<>();


    @Override
    public ToDo save(ToDo domain) {
        ToDo result = toDos.get(domain.getId());
        if(result != null) {
            result.setModified(LocalDateTime.now());
            result.setDescription(domain.getDescription());
            result.setCompleted(domain.isCompleted());
            domain = result;
        }
        toDos.put(domain.getId(), domain);
        return toDos.get(domain.getId());

    }

    @Override
    public Iterable<ToDo> save(Collection<ToDo> domains) {
        domains.forEach(this::save);
        return findAll();
    }

    @Override
    public void delete(ToDo domain) {
        toDos.remove(domain.getId());
    }

    @Override
    public ToDo findById(String id) {
        return toDos.get(id);
    }

    @Override
    public Iterable<ToDo> findAll() {
        return toDos.entrySet().stream().sorted(entryComparator).map(Map.Entry::getValue).collect(Collectors.toList());
    }

    private Comparator<Map.Entry<String,ToDo>> entryComparator = (Map.Entry<String, ToDo> o1, Map.Entry<String, ToDo> o2) -> {
        return o1.getValue().getCreated().compareTo(o2.getValue().getCreated());
    };
}

package com.apress.todo.validation;

import com.fasterxml.jackson.annotation.JsonInclude;

import java.util.ArrayList;
import java.util.List;

public class ToDoValidationError {

    @JsonInclude(JsonInclude.Include.NON_EMPTY)
    private List<String> errors = new ArrayList<>();

    private final String errorMessage;

    public ToDoValidationError(String errorMessage) {
        this.errorMessage = errorMessage;
    }

    public void addValidationError(String error) {
        errors.add(error);
    }

    public List<String> getErrors() {
        return errors;
    }

    public String getErrorMessage() {
        return errorMessage;
    }
}

package com.apress.todo.validation;

import org.springframework.validation.Errors;
import org.springframework.validation.ObjectError;

public class ToDoValidationErrorBuilder {

    public static ToDoValidationError fromBindingErrors(Errors errors) {
        ToDoValidationError error = new ToDoValidationError("Validation failed. " + errors.getErrorCount() + " error(s)");
        for (ObjectError objectError : errors.getAllErrors()) {
            error.addValidationError(objectError.getDefaultMessage());
        }
        return error;
    }
}

package com.apress.todo.controller;

import com.apress.todo.domain.ToDo;
import com.apress.todo.domain.ToDoBuilder;
import com.apress.todo.repository.CommonRepository;
import com.apress.todo.validation.ToDoValidationError;
import com.apress.todo.validation.ToDoValidationErrorBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.validation.Errors;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import javax.validation.Valid;
import java.net.URI;

@RestController
@RequestMapping("/api")
public class ToDoController {

    private CommonRepository<ToDo> repository;

    @Autowired
    public ToDoController(CommonRepository<ToDo> repository) {
        this.repository = repository;
    }

    @GetMapping("/todo") //@RequestMapping(value="/todo", method = {RequestMethod.GET})
    public ResponseEntity<Iterable<ToDo>> getToDos(){
        return ResponseEntity.ok(repository.findAll());
    }

    @GetMapping("/todo/{id}")
    public ResponseEntity<ToDo> getToDoById(@PathVariable String id){
        return ResponseEntity.ok(repository.findById(id));
    }

    @PatchMapping("/todo/{id}")
    public ResponseEntity<ToDo> setCompleted(@PathVariable String id){
        ToDo result = repository.findById(id);
        result.setCompleted(true);
        repository.save(result);
        URI location = ServletUriComponentsBuilder.fromCurrentRequest()
                .buildAndExpand(result.getId()).toUri();

        return ResponseEntity.ok().header("Location",location.toString()).build();
    }

    @RequestMapping(value="/todo", method = {RequestMethod.POST,RequestMethod.PUT})
    public ResponseEntity<?> createToDo(@Valid @RequestBody ToDo toDo, Errors errors){
        if (errors.hasErrors()) {
            return ResponseEntity.badRequest().body(ToDoValidationErrorBuilder.fromBindingErrors(errors));
        }

        ToDo result = repository.save(toDo);
        URI location = ServletUriComponentsBuilder.fromCurrentRequest().path("/{id}")
                .buildAndExpand(result.getId()).toUri();
        return ResponseEntity.created(location).build();
    }

    @DeleteMapping("/todo/{id}")
    public ResponseEntity<ToDo> deleteToDo(@PathVariable String id){
        repository.delete(ToDoBuilder.create().withId(id).build());
        return ResponseEntity.noContent().build();
    }

    @DeleteMapping("/todo")
    public ResponseEntity<ToDo> deleteToDo(@RequestBody ToDo toDo){
        repository.delete(toDo);
        return ResponseEntity.noContent().build();
    }

    @ExceptionHandler
    @ResponseStatus(value = HttpStatus.BAD_REQUEST)
    public ToDoValidationError handleException(Exception exception) {
        return new ToDoValidationError(exception.getMessage());
    }

}