Retrofit基础之：GET与POST请求

 Retrofit是大名鼎鼎的Square公司搞出来的一个网络请求框架。其本身是对okhttp做了一层封装，网络请求都交给给了Okhttp。
 Retrofit只需要通过简单的配置就能进行网络请求。开源地址：http://square.github.io/retrofit/
 开始学点最简单地GET及POST请求，直接上代码，文字表达见注释：
 第一步：首先定义接口类：

/**
 * description：接口定义，定义网络请求的路径
 * 作者：ldm
 * 时间：20172017/4/28 09:58
 * 邮箱：1786911211@qq.com
 */
public interface RetrofitApi {
    //GET方式请求，对应的注解是@GET
    @GET("users/{user}/repos")
    Call<List<GithubModel>> getUserInfo(@Path("user") String user);
    //GET方式请求，对应的注解是@POST
    @POST("mobile/login.json")
    Call<ResponseModel<String>> login(@Body UserModel userModel);//POST请求方式，@Body中则是传入的参数，会转成json格式传到服务器
}

第二步：确实接口请求参数及返回数据格式，定义实体类：
1,示例中GET方式返回数据对应 实体类，有点长，太长

/**
 * description：
 * 作者：ldm
 * 时间：20172017/4/28 09:59
 * 邮箱：1786911211@qq.com
 */
public class GithubModel {
    private int id;
    private String name;
    private String full_name;
    private OwnerBean owner;
    @SerializedName("private")
    private boolean privateX;
    private String html_url;
    private String description;
    private boolean fork;
    private String url;
    private String forks_url;
    private String keys_url;
    private String collaborators_url;
    private String teams_url;
    private String hooks_url;
    private String issue_events_url;
    private String events_url;
    private String assignees_url;
    private String branches_url;
    private String tags_url;
    private String blobs_url;
    private String git_tags_url;
    private String git_refs_url;
    private String trees_url;
    private String statuses_url;
    private String languages_url;
    private String stargazers_url;
    private String contributors_url;
    private String subscribers_url;
    private String subscription_url;
    private String commits_url;
    private String git_commits_url;
    private String comments_url;
    private String issue_comment_url;
    private String contents_url;
    private String compare_url;
    private String merges_url;
    private String archive_url;
    private String downloads_url;
    private String issues_url;
    private String pulls_url;
    private String milestones_url;
    private String notifications_url;
    private String labels_url;
    private String releases_url;
    private String deployments_url;
    private String created_at;
    private String updated_at;
    private String pushed_at;
    private String git_url;
    private String ssh_url;
    private String clone_url;
    private String svn_url;
    private String homepage;
    private int size;
    private int stargazers_count;
    private int watchers_count;
    private String language;
    private boolean has_issues;
    private boolean has_projects;
    private boolean has_downloads;
    private boolean has_wiki;
    private boolean has_pages;
    private int forks_count;
    private Object mirror_url;
    private int open_issues_count;
    private int forks;
    private int open_issues;
    private int watchers;
    private String default_branch;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getFull_name() {
        return full_name;
    }

    public void setFull_name(String full_name) {
        this.full_name = full_name;
    }

    public OwnerBean getOwner() {
        return owner;
    }

    public void setOwner(OwnerBean owner) {
        this.owner = owner;
    }

    public boolean isPrivateX() {
        return privateX;
    }

    public void setPrivateX(boolean privateX) {
        this.privateX = privateX;
    }

    public String getHtml_url() {
        return html_url;
    }

    public void setHtml_url(String html_url) {
        this.html_url = html_url;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public boolean isFork() {
        return fork;
    }

    public void setFork(boolean fork) {
        this.fork = fork;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getForks_url() {
        return forks_url;
    }

    public void setForks_url(String forks_url) {
        this.forks_url = forks_url;
    }

    public String getKeys_url() {
        return keys_url;
    }

    public void setKeys_url(String keys_url) {
        this.keys_url = keys_url;
    }

    public String getCollaborators_url() {
        return collaborators_url;
    }

    public void setCollaborators_url(String collaborators_url) {
        this.collaborators_url = collaborators_url;
    }

    public String getTeams_url() {
        return teams_url;
    }

    public void setTeams_url(String teams_url) {
        this.teams_url = teams_url;
    }

    public String getHooks_url() {
        return hooks_url;
    }

    public void setHooks_url(String hooks_url) {
        this.hooks_url = hooks_url;
    }

    public String getIssue_events_url() {
        return issue_events_url;
    }

    public void setIssue_events_url(String issue_events_url) {
        this.issue_events_url = issue_events_url;
    }

    public String getEvents_url() {
        return events_url;
    }

    public void setEvents_url(String events_url) {
        this.events_url = events_url;
    }

    public String getAssignees_url() {
        return assignees_url;
    }

    public void setAssignees_url(String assignees_url) {
        this.assignees_url = assignees_url;
    }

    public String getBranches_url() {
        return branches_url;
    }

    public void setBranches_url(String branches_url) {
        this.branches_url = branches_url;
    }

    public String getTags_url() {
        return tags_url;
    }

    public void setTags_url(String tags_url) {
        this.tags_url = tags_url;
    }

    public String getBlobs_url() {
        return blobs_url;
    }

    public void setBlobs_url(String blobs_url) {
        this.blobs_url = blobs_url;
    }

    public String getGit_tags_url() {
        return git_tags_url;
    }

    public void setGit_tags_url(String git_tags_url) {
        this.git_tags_url = git_tags_url;
    }

    public String getGit_refs_url() {
        return git_refs_url;
    }

    public void setGit_refs_url(String git_refs_url) {
        this.git_refs_url = git_refs_url;
    }

    public String getTrees_url() {
        return trees_url;
    }

    public void setTrees_url(String trees_url) {
        this.trees_url = trees_url;
    }

    public String getStatuses_url() {
        return statuses_url;
    }

    public void setStatuses_url(String statuses_url) {
        this.statuses_url = statuses_url;
    }

    public String getLanguages_url() {
        return languages_url;
    }

    public void setLanguages_url(String languages_url) {
        this.languages_url = languages_url;
    }

    public String getStargazers_url() {
        return stargazers_url;
    }

    public void setStargazers_url(String stargazers_url) {
        this.stargazers_url = stargazers_url;
    }

    public String getContributors_url() {
        return contributors_url;
    }

    public void setContributors_url(String contributors_url) {
        this.contributors_url = contributors_url;
    }

    public String getSubscribers_url() {
        return subscribers_url;
    }

    public void setSubscribers_url(String subscribers_url) {
        this.subscribers_url = subscribers_url;
    }

    public String getSubscription_url() {
        return subscription_url;
    }

    public void setSubscription_url(String subscription_url) {
        this.subscription_url = subscription_url;
    }

    public String getCommits_url() {
        return commits_url;
    }

    public void setCommits_url(String commits_url) {
        this.commits_url = commits_url;
    }

    public String getGit_commits_url() {
        return git_commits_url;
    }

    public void setGit_commits_url(String git_commits_url) {
        this.git_commits_url = git_commits_url;
    }

    public String getComments_url() {
        return comments_url;
    }

    public void setComments_url(String comments_url) {
        this.comments_url = comments_url;
    }

    public String getIssue_comment_url() {
        return issue_comment_url;
    }

    public void setIssue_comment_url(String issue_comment_url) {
        this.issue_comment_url = issue_comment_url;
    }

    public String getContents_url() {
        return contents_url;
    }

    public void setContents_url(String contents_url) {
        this.contents_url = contents_url;
    }

    public String getCompare_url() {
        return compare_url;
    }

    public void setCompare_url(String compare_url) {
        this.compare_url = compare_url;
    }

    public String getMerges_url() {
        return merges_url;
    }

    public void setMerges_url(String merges_url) {
        this.merges_url = merges_url;
    }

    public String getArchive_url() {
        return archive_url;
    }

    public void setArchive_url(String archive_url) {
        this.archive_url = archive_url;
    }

    public String getDownloads_url() {
        return downloads_url;
    }

    public void setDownloads_url(String downloads_url) {
        this.downloads_url = downloads_url;
    }

    public String getIssues_url() {
        return issues_url;
    }

    public void setIssues_url(String issues_url) {
        this.issues_url = issues_url;
    }

    public String getPulls_url() {
        return pulls_url;
    }

    public void setPulls_url(String pulls_url) {
        this.pulls_url = pulls_url;
    }

    public String getMilestones_url() {
        return milestones_url;
    }

    public void setMilestones_url(String milestones_url) {
        this.milestones_url = milestones_url;
    }

    public String getNotifications_url() {
        return notifications_url;
    }

    public void setNotifications_url(String notifications_url) {
        this.notifications_url = notifications_url;
    }

    public String getLabels_url() {
        return labels_url;
    }

    public void setLabels_url(String labels_url) {
        this.labels_url = labels_url;
    }

    public String getReleases_url() {
        return releases_url;
    }

    public void setReleases_url(String releases_url) {
        this.releases_url = releases_url;
    }

    public String getDeployments_url() {
        return deployments_url;
    }

    public void setDeployments_url(String deployments_url) {
        this.deployments_url = deployments_url;
    }

    public String getCreated_at() {
        return created_at;
    }

    public void setCreated_at(String created_at) {
        this.created_at = created_at;
    }

    public String getUpdated_at() {
        return updated_at;
    }

    public void setUpdated_at(String updated_at) {
        this.updated_at = updated_at;
    }

    public String getPushed_at() {
        return pushed_at;
    }

    public void setPushed_at(String pushed_at) {
        this.pushed_at = pushed_at;
    }

    public String getGit_url() {
        return git_url;
    }

    public void setGit_url(String git_url) {
        this.git_url = git_url;
    }

    public String getSsh_url() {
        return ssh_url;
    }

    public void setSsh_url(String ssh_url) {
        this.ssh_url = ssh_url;
    }

    public String getClone_url() {
        return clone_url;
    }

    public void setClone_url(String clone_url) {
        this.clone_url = clone_url;
    }

    public String getSvn_url() {
        return svn_url;
    }

    public void setSvn_url(String svn_url) {
        this.svn_url = svn_url;
    }

    public String getHomepage() {
        return homepage;
    }

    public void setHomepage(String homepage) {
        this.homepage = homepage;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public int getStargazers_count() {
        return stargazers_count;
    }

    public void setStargazers_count(int stargazers_count) {
        this.stargazers_count = stargazers_count;
    }

    public int getWatchers_count() {
        return watchers_count;
    }

    public void setWatchers_count(int watchers_count) {
        this.watchers_count = watchers_count;
    }

    public String getLanguage() {
        return language;
    }

    public void setLanguage(String language) {
        this.language = language;
    }

    public boolean isHas_issues() {
        return has_issues;
    }

    public void setHas_issues(boolean has_issues) {
        this.has_issues = has_issues;
    }

    public boolean isHas_projects() {
        return has_projects;
    }

    public void setHas_projects(boolean has_projects) {
        this.has_projects = has_projects;
    }

    public boolean isHas_downloads() {
        return has_downloads;
    }

    public void setHas_downloads(boolean has_downloads) {
        this.has_downloads = has_downloads;
    }

    public boolean isHas_wiki() {
        return has_wiki;
    }

    public void setHas_wiki(boolean has_wiki) {
        this.has_wiki = has_wiki;
    }

    public boolean isHas_pages() {
        return has_pages;
    }

    public void setHas_pages(boolean has_pages) {
        this.has_pages = has_pages;
    }

    public int getForks_count() {
        return forks_count;
    }

    public void setForks_count(int forks_count) {
        this.forks_count = forks_count;
    }

    public Object getMirror_url() {
        return mirror_url;
    }

    public void setMirror_url(Object mirror_url) {
        this.mirror_url = mirror_url;
    }

    public int getOpen_issues_count() {
        return open_issues_count;
    }

    public void setOpen_issues_count(int open_issues_count) {
        this.open_issues_count = open_issues_count;
    }

    public int getForks() {
        return forks;
    }

    public void setForks(int forks) {
        this.forks = forks;
    }

    public int getOpen_issues() {
        return open_issues;
    }

    public void setOpen_issues(int open_issues) {
        this.open_issues = open_issues;
    }

    public int getWatchers() {
        return watchers;
    }

    public void setWatchers(int watchers) {
        this.watchers = watchers;
    }

    public String getDefault_branch() {
        return default_branch;
    }

    public void setDefault_branch(String default_branch) {
        this.default_branch = default_branch;
    }

    public static class OwnerBean {

        private String login;
        private int id;
        private String avatar_url;
        private String gravatar_id;
        private String url;
        private String html_url;
        private String followers_url;
        private String following_url;
        private String gists_url;
        private String starred_url;
        private String subscriptions_url;
        private String organizations_url;
        private String repos_url;
        private String events_url;
        private String received_events_url;
        private String type;
        private boolean site_admin;

        public String getLogin() {
            return login;
        }

        public void setLogin(String login) {
            this.login = login;
        }

        public int getId() {
            return id;
        }

        public void setId(int id) {
            this.id = id;
        }

        public String getAvatar_url() {
            return avatar_url;
        }

        public void setAvatar_url(String avatar_url) {
            this.avatar_url = avatar_url;
        }

        public String getGravatar_id() {
            return gravatar_id;
        }

        public void setGravatar_id(String gravatar_id) {
            this.gravatar_id = gravatar_id;
        }

        public String getUrl() {
            return url;
        }

        public void setUrl(String url) {
            this.url = url;
        }

        public String getHtml_url() {
            return html_url;
        }

        public void setHtml_url(String html_url) {
            this.html_url = html_url;
        }

        public String getFollowers_url() {
            return followers_url;
        }

        public void setFollowers_url(String followers_url) {
            this.followers_url = followers_url;
        }

        public String getFollowing_url() {
            return following_url;
        }

        public void setFollowing_url(String following_url) {
            this.following_url = following_url;
        }

        public String getGists_url() {
            return gists_url;
        }

        public void setGists_url(String gists_url) {
            this.gists_url = gists_url;
        }

        public String getStarred_url() {
            return starred_url;
        }

        public void setStarred_url(String starred_url) {
            this.starred_url = starred_url;
        }

        public String getSubscriptions_url() {
            return subscriptions_url;
        }

        public void setSubscriptions_url(String subscriptions_url) {
            this.subscriptions_url = subscriptions_url;
        }

        public String getOrganizations_url() {
            return organizations_url;
        }

        public void setOrganizations_url(String organizations_url) {
            this.organizations_url = organizations_url;
        }

        public String getRepos_url() {
            return repos_url;
        }

        public void setRepos_url(String repos_url) {
            this.repos_url = repos_url;
        }

        public String getEvents_url() {
            return events_url;
        }

        public void setEvents_url(String events_url) {
            this.events_url = events_url;
        }

        public String getReceived_events_url() {
            return received_events_url;
        }

        public void setReceived_events_url(String received_events_url) {
            this.received_events_url = received_events_url;
        }

        public String getType() {
            return type;
        }

        public void setType(String type) {
            this.type = type;
        }

        public boolean isSite_admin() {
            return site_admin;
        }

        public void setSite_admin(boolean site_admin) {
            this.site_admin = site_admin;
        }
    }
}

2，POST请求参数及响应实体类：

public class UserModel {
    private String userName;
    private String userPwd;

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPwd() {
        return userPwd;
    }

    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }
}

public class ResponseModel<T> implements Serializable {
    //请求结果响应码：0表示服务器返回成功，其它表示失败
    private int code;
    //信息提示，如成功则提示操作成功，失败则提示失败原因
    private String message;
    //服务器返回的数据
    private T result;

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public T getResult() {
        return result;
    }

    public void setResult(T result) {
        this.result = result;
    }
}

第三步：在代码中实现网络请求：

public class RetrofitActivity extends AppCompatActivity implements View.OnClickListener {
    private Button retrofit_get;
    private Button retrofit_post;
    private TextView result_tv;
    private static final String GET_BASE_URL = "https://api.github.com/";
    private static final String POST_BASE_URL = "http://192.168.2.13:8083/";

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_retrofit);
        initViews();
    }

    private void initViews() {
        this.result_tv = (TextView) findViewById(R.id.result_tv);
        this.retrofit_get = (Button) findViewById(R.id.retrofit_get);
        this.retrofit_post = (Button) findViewById(R.id.retrofit_post);
        this.retrofit_get.setOnClickListener(this);
        this.retrofit_post.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.retrofit_get:
                requestByGET("ldm520");
                break;
            case R.id.retrofit_post:
                UserModel model = new UserModel();
                model.setUserName("admin");
                model.setUserPwd("123456");
                requestByPOST(model);
                break;
        }
    }

    /**
     * @description 通过GET方法进行网络请求
     * @author ldm
     * @time 2017/4/28 10:38
     */
    private void requestByGET(String user) {
        //获取实例
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(GET_BASE_URL)//设置baseUrl
                .addConverterFactory(GsonConverterFactory.create())//添加JSON对应转换器
                .build();
        //通过Retrofit.create()方法获取api
        RetrofitApi api = retrofit.create(RetrofitApi.class);
        //完整的get请求地址就是：https://api.github.com/users/ldm520/repos
        Call<List<GithubModel>> responseCall = api.getUserInfo(user);
        //采用异步请求
        responseCall.enqueue(new Callback<List<GithubModel>>() {
            @Override
            public void onResponse(Call<List<GithubModel>> call, Response<List<GithubModel>> response) {
                //获取响应结果
                List<GithubModel> result = response.body();
                if (result.size() > 0) {
                    result_tv.setText("共获取到" + result.size() + "条数据,第一条数据部分内容是：" + "\n blob_url:" + result.get(0).getBlobs_url()
                            + "\n description:" + result.get(0).getDescription() + "...");
                }
            }

            @Override
            public void onFailure(Call<List<GithubModel>> call, Throwable t) {
                Toast.makeText(RetrofitActivity.this, "请求失败", Toast.LENGTH_LONG).show();
            }
        });
    }

    /**
     * @description 通过POST方法进行网络请求
     * @author ldm
     * @time 2017/4/28 10:39
     */
    private void requestByPOST(UserModel model) {
        //获取实例
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(POST_BASE_URL)//设置baseUrl
                .addConverterFactory(GsonConverterFactory.create())//添加JSON对应转换器
                .build();
        //通过Retrofit.create()方法获取api
        RetrofitApi api = retrofit.create(RetrofitApi.class);
        //完整的get请求地址就是：http://192.168.2.13:8083/mobile/login.json
        api.login(model).enqueue(new Callback<ResponseModel<String>>() {
            @Override
            public void onResponse(Call<ResponseModel<String>> call, Response<ResponseModel<String>> response) {
                if (response.body().getCode() == 0) {
                    Toast.makeText(RetrofitActivity.this, "登录成功", Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(RetrofitActivity.this, "登录失败", Toast.LENGTH_LONG).show();
                }
            }

            @Override
            public void onFailure(Call<ResponseModel<String>> call, Throwable t) {
                Toast.makeText(RetrofitActivity.this, "登录失败", Toast.LENGTH_LONG).show();
            }
        });
    }
}

把简单地布局文件也贴下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:padding="16dp">

    <Button
            android:id="@+id/retrofit_get"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Retrofit之GET请求"/>

    <Button
            android:id="@+id/retrofit_post"
            android:layout_width="match_parent"
            android:layout_marginTop="15dp"
            android:layout_height="wrap_content"
            android:text="Retrofit之POST请求"/>

    <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/result_tv"
            android:layout_marginTop="10dp"/>
</LinearLayout>

刚开始学习Retrofit，代码潦草，有待优化，继续学习中….。对了，不要忘记在AndroidManifest.xml中添加

    <uses-permission android:name="android.permission.INTERNET"/>