一、使用lombok简化代码

lombok提供了很多注解，在编译时候生成java代码，代替了手工编写一些简单的代码，使程序员可以关注更重要的实现。

二、

以model为例

public class DataDemo {    private Integer id;    private String name;    private Date time;}

一下是添加不同lombok注解的编译结果示例，编译结果很简单，不需要做什么说明，直接上代码：

@Getter / @Setter

public class GetterSetterDemo {    private Integer id;    private String name;    private Date time;    public GetterSetterDemo() {  }    public Integer getId() { return this.id; }    public String getName() { return this.name; }    public Date getTime() { return this.time; }    public void setId(Integer id) { this.id = id; }    public void setName(String name) { this.name = name; }    public void setTime(Date time) { this.time = time; }}

@ToString

model上添加注解：@ToString(exclude = {"id"}, includeFieldNames = false)

public class ToStringDemo {    private Integer id;    private String name;    private Date time;    public ToStringDemo() {  }    public String toString() {        return "ToStringDemo(" + this.name + ", " + this.time + ")";    }}

@Data

@Data 注解相当于 Getter + Setter + ToString + @RequiredArgsConstrutor，可以用在pojo上

public class DataDemo {    private Integer id;    private String name;    private Date time;    public DataDemo() {  }    public Integer getId() { return this.id;}    public String getName() { return this.name; }    public Date getTime() { return this.time; }    public void setId(Integer id) { this.id = id; }    public void setName(String name) { this.name = name; }    public void setTime(Date time) { this.time = time; }    public boolean equals(Object o) { ... }    protected boolean canEqual(Object other) { ... }    public int hashCode() { ... }    public String toString() {        return "DataDemo(id=" + this.getId() + ", name=" + this.getName() + ", time=" + this.getTime() + ")";    }}

@Builder

public class BuilderDemo {    private Integer id;    private String name;    private Date time;    @ConstructorProperties({
     "id", "name", "time"})    BuilderDemo(Integer id, String name, Date time) {        this.id = id;        this.name = name;        this.time = time;    }    public static BuilderDemo.BuilderDemoBuilder builder() {        return new BuilderDemo.BuilderDemoBuilder();    }    public static class BuilderDemoBuilder {        private Integer id;        private String name;        private Date time;        BuilderDemoBuilder() {        }        public BuilderDemo.BuilderDemoBuilder id(Integer id) {            this.id = id;            return this;        }        public BuilderDemo.BuilderDemoBuilder name(String name) {            this.name = name;            return this;        }        public BuilderDemo.BuilderDemoBuilder time(Date time) {            this.time = time;            return this;        }        public BuilderDemo build() {            return new BuilderDemo(this.id, this.name, this.time);        }        public String toString() {            return "BuilderDemo.BuilderDemoBuilder(id=" + this.id + ", name=" + this.name + ", time=" + this.time + ")";        }    }}

@AllArgsConstructor    全部参数构造函数

@NoArgsConstructor   无参数构造函数

@RequiredArgsConstructor   NoNull参数和常量构造函数

/**@AllArgsConstructor*/public class AllArgsConstructorDemo {    private Integer id;    private String name;    private Date time;    @ConstructorProperties({
     "id", "name", "time"})    public AllArgsConstructorDemo(Integer id, String name, Date time) {        this.id = id;        this.name = name;        this.time = time;    }}/**@NoArgsConstructor*/public class NoArgsConstructorDemo {    private Integer id;    private String name;    private Date time;    public NoArgsConstructorDemo() {  }}/**@RequiredArgsConstructor(staticName = "of")*/public class RequiredArgsConstructorDemo {    private Integer id;    private String name;    private Date time;    private RequiredArgsConstructorDemo() {  }    public static RequiredArgsConstructorDemo of() {        return new RequiredArgsConstructorDemo();    }}/**@RequiredArgsConstructor(staticName = "of")*/public class RequiredArgsConstructorDemo {    private Integer id;    @NonNull    private String name;    @NonNull    private Date time;    @ConstructorProperties({
     "name", "time"})    private RequiredArgsConstructorDemo(@NonNull String name, @NonNull Date time) {        if(name == null) {            throw new NullPointerException("name");        } else if(time == null) {            throw new NullPointerException("time");        } else {            this.name = name;            this.time = time;        }    }    public static RequiredArgsConstructorDemo of(@NonNull String name, @NonNull Date time) {        return new RequiredArgsConstructorDemo(name, time);    }}

@Value

public final class ValueDemo {    private final Integer id;    private final String name;    private final Date time;    @ConstructorProperties({
     "id", "name", "time"})    public ValueDemo(Integer id, String name, Date time) {        this.id = id;        this.name = name;        this.time = time;    }    public Integer getId() {        return this.id;    }    public String getName() {        return this.name;    }    public Date getTime() {        return this.time;    }    public boolean equals(Object o) { ... }    public int hashCode() { ... }    public String toString() {        return "ValueDemo(id=" + this.getId() + ", name=" + this.getName() + ", time=" + this.getTime() + ")";    }}